26 February 2022 - Southern Regional Power Committee

Anusha

Text Box

26 February 2022

Minutes of 100thMeetingof PCSC held on 17th February, 2022 (online through WebEx) Page 1/19

Table of Contents

1. Introduction ......................................................................................................................................... 2

2. Confirmation of Minutes of last PCSC meeting .................................................................................. 2

3. Grid Occurrences ................................................................................................................................. 2

4. Compliance by Constituents (Submitting status/remedial measures/certificate) ........................ 5

4.1. Status of implementation of pending Recommendations of PCSC .................................................. 5

4.2. Remedial measures for "Transmission Elements under Forced Outage" ....................................... 5

4.3. Certificate for Healthiness of Batteries .............................................................................................. 6

5. Islanding Schemes (IS) of Southern Region ...................................................................................... 7

5.1 Implementation Status ........................................................................................................................ 7

5.2 Creation of SCADA Display to Monitor Vital Parameters of the Island ......................................... 10

5.3 Revision of U/f & O/f Settings of Participating Generators of various Islanding Schemes of

Southern Region ......................................................................................................................................... 12

5.4 Furnishing of Monthly Certificate on Healthiness of Islanding Schemes by Generators/

Transmission Utilities / SLDCs/ DISCOMS ............................................................................................... 15

6. Protection Management system (PMS) project .............................................................................. 17

6.1. PMS Review Meeting ......................................................................................................................... 17

6.2. PMS Nodal Officer Details ................................................................................................................. 18

7. Items for information ........................................................................................................................ 18

7.1. CEA technical Standards ................................................................................................................... 18

7.2. Network reconfigurations................................................................................................................. 18

8. Other Protection Issues, if any, with the permission of the Chair ................................................. 18

9. Sending Agenda items for the PCSC meetings ................................................................................. 19

10. Date of next PCSC meeting ................................................................................................................ 19


Southern Regional Power Committee Bengaluru

Minutes of the 100th meeting of Protection Coordination Sub-Committee (PCSC-100) of SRPC held on 17th February, 2022 through VC/Online

1. Introduction

The 100th meeting of Protection Coordination Sub-Committee (PCSC-100) of SRPC was held

in online mode through Webex on 17th February, 2022. The list of participants is at

Annexure-A.

The meeting commenced with welcoming of new Member Secretary of SRPC, Shri Asit Singh

and Chief Engineer of KPTCL Shri Subhash Bhosle by Superintending Engineer (P&SS).

Congratulating all members of Protection committee of SRPC on its 100th meeting, Member

Secretary (MS), SRPC briefed the forum on the following:

• Placed on record the PCSC member’s efforts & contribution in maintaining the regional

system healthy and active participation in resolving protection related issues.

• Expressed his gratitude to all protection engineers of SR region for their active

participation in PCSC meetings and requested their active participation in future as well.

• Requested all constituents to make efforts towards closing of all pending PCSC

recommendations, Protection Audit remarks, SPS and Islanding scheme reviews, if any,

in the interest of stable grid operation.

Then, Superintending Engineer (P&SS), SRPC and Convener of Protection Coordination

Sub-Committee of SRPC took up the Agenda for deliberations.

2. Confirmation of Minutes of last PCSC meeting

Minutes of 99th Protection Coordination Sub-Committee meeting held on 17th December, 2021 was issued vide letter No: SRPC/SE-III/PCSC-99/2021-22/ dated 20th January, 2022. No comments had been received from the Utilities. Minutes of PCSC-99 meeting were confirmed.

3. Grid Occurrences

Agenda:

3.1. Grid Occurrences which took place during the period December 2021 – January 2022,

given at Annexure-I, would be discussed in the meeting.

I. The Grid Disturbances (GDs) would be discussed in the following order:

Name of the Utility who would present the GD in all its details

SN of the GD as per Annexure-I

APGENCO I.A.1, I.A.5

KPTCL I.A.2

KPCL I.A.3

APTRANSCO I.A.4, I.A.6, I.A.8

TANTRANSCO I.A.7


II. The Grid Disturbances (GDs) of RE generators would be discussed in the following

order:

Name of the Utilitywho would present the GD in all its details

SN of the GD as per Annexure-I

OSTRO KANNADA I.B.1

III. The Grid Incidents (GIs) would be discussed in the following order:

Name of the Utility who would present the GI in all its details

SN of the GI as per Annexure-I

NPCIL-KKNPP II.1,

PGCIL SR-II II.2, II.5

KPCL II.3, II.4

KSEBL II.6

TSTRANSCO II.7, II.10

NPCIL-Kaiga II.8

APTRANCSO II.9

IV. W.r.t. failure or non-operation of A/R events included in Annexure-I at Item No. III,

the concerned Utilities, as listed below, shall furnish the reasons for the same, along with remedial action taken, to SRPC latest by 10.02.2022 so that the same can be closed without deliberations. Else, the same shall be presented by respective Utilities in the meeting:

SN of A/R event as per Annexure-I

Utilities, who would furnish reasons for A/R failure or non-operation, along with remedial action taken

III.1 NNTPP

III.2 , III.4 KSEBL & TANTRANSCO

III.3 NPCIL(Kaiga) & KPTCL

III.5 KPTCL & KSEBL

III.6 TSGENCO & APTRANSCO

III.7 TANTRANSCO

III.8 APGENCO

III.9 TSGENCO & KPTCL

III.10 APGENCO

III.11 PGCIL-SR-II

V. W.r.t. PLCC mal-operation events included in Annexure-I at Item No. IV, the

concerned Utilities, as listed below, shall furnish the reasons for the same, along with remedial action taken, to SRPC latest by 10.02.2022 so that the same can be closed without deliberations. Else, the same shall be presented by respective Utilities in the meeting:

SN of PLCC event as per Annexure-I

Utilities, who would furnish reasons for A/R failure or non-operation, along with remedial action taken

IV.1 APTRANSCO & TSTRANSCO

IV.2 APTRANSCO

1V.3 PGCIL (SR-I) & APTRANSCO

IV.4 TANTRANSCO


a) All the utilities, as listed above, shall give a presentation (for not more than 10 minutes

per GD; for not more than 5 minutes per GI) on the GDs & GIs mentioned against them. b) The presentation shall cover all pertinent aspects such as Antecedent conditions,

Bus-configuration, Reasons of GD/ GI occurrence, Relevant Diagrams showing location of the fault, Bus bar arrangement/configuration of feeders and other connected equipment with proper CB positions (OPEN/ CLOSE) at the time of occurrence of the fault, Type of protections operated, Substantiation of the protections operated by relevant DRs & ELs, Reasons for protection systems mal-operation/non-operation, Remedial measures taken/ proposed, etc.

c) SRLDC shall furnish the PMU plots for all the above grid occurrences (with delayed fault clearance) to SRPC Secretariat by 10.02.2022, and present the same in the meeting.

d) Constituents shall furnish the following details to SRPC by 10.02.2022 (in WORD format) in respect of all the above grid occurrences (GD, GI) to have fruitful discussions:

(i) Detailed analysis of the events (ii) SLD or equivalent pictorial representation clearly showing:

a. Location of fault with distance b. Fault details with type &relay indications c. CT/PT/CVT rating details with location d. Bus-bar arrangement/ Configuration of feeders e. CB positions (OPEN/ CLOSE) at the time of fault f. Isolator & Earth-switch positions (OPEN/CLOSE) g. Voltage, frequency & power flows with direction at the time of fault

(iii) Output of Event logger & Disturbance recorder (iv) Remedial Action(s) taken (v) Relay setting details

Deliberations:

3.1.1 The Grid disturbances and Grid incidents that had occurred the period December 2021 – January 2022, were discussed in the meeting. Respective utilities presented the tripping details. The deliberations and recommendations of the PCSC forum are at Annexure–B for needful action by all concerned.

3.1.2 PMU plots of the events submitted by SRLDC is at Annexure-E 3.1.3 The matter of timely uploading of tripping files, which helps in analyzing the events for

corrective actions/solutions required was highlighted and all constituents were requested to ensure that the files as per regulatory stipulations are uploaded on SRLDC tripping portal.

3.2 In compliance of Regulations 5.2 (r) of IEGC, which is given below:

Agenda: “5.2 System Security Aspects

(r) All the Users, STU/SLDC and CTU shall send information/data including disturbance recorder/sequential event recorder output to RLDC within [24 hours] for purpose of analysis of any grid disturbance/event. No User, SLDC/STU or CTU shall block any data/information required by the RLDC and RPC for maintaining reliability and security of the grid and for analysis of an event.”

a) Constituents are required to furnish the following information in respect of Grid

Occurrences(GD/GI) within 24 hours of occurrence of the same to SRLDC/ SRPC: (i) First Information Report (FIR) (ii) Event Logger (EL) output (iii) Disturbance Recorder (DR) output (iv) Trip event analysis report-TR (with pre and post fault system conditions)


b) Non-furnishing of tripping details (FIR/DR/EL/TR) for the period 16.11.2021 – 15.01.2022 had been brought to Constituents’ notice vide the following SRPC letters:

i. No. SRPC/ SE-III/ PCSC/ 2021/2148-62 dated 08.12.2021 ii. No. SRPC/ SE-III/ PCSC/ 2022/ dated 11.01.2022

c) Non-compliance in this regard would be discussed in the meeting.

Deliberations: 3.2.1 Non-furnishing of tripping details (FIR/DR/EL/TR) for the period 16.11.2021 – 15.01.2022

were discussed in the meeting. Attention of the constituents was drawn to the fortnightly letters issued in this respect and the relevance of timely uploading of the tripping details, which facilitates appropriate analysis of the events, was re-emphasized. All constituents were requested to ensure uploading of all tripping files in a timely manner, particularly FIR/DR/EL immediately after the event, as mandated by IEGC.

4. Compliance by Constituents (Submitting status/remedial measures/certificate)

4.1. Status of implementation of pending Recommendations of PCSC

Agenda: a) The status of implementation of PCSC recommendations (up to 99th PCSC meeting),

which are pending, is at Annexure-II.

b) The latest status on the same may please be sent latest by 11.02.2022, to place the same before the sub-committee.

Deliberations: 4.1.1 The status of implementation of pending PCSC recommendations was discussed in the

meeting. It was mentioned that the P-Rec files were being circulated regularly for updation, however, many recommendations were observed to be pending. The accumulation of the recommendations need to be avoided, from the perspective of effective implementation as well as monitoring. Accordingly, all the constituents were requested to comply with the recommendations of the forum, which were decided for the safe and beneficial operation of the grid, on priority basis. The updated status of the same as on 25.02.2022 is at Annexure–C.

4.2. Remedial measures for "Transmission Elements under Forced Outage"

Agenda: a) The Constituents are requested to furnish the remedial measures/ actions taken by

them for the tripping events, as circulated vide this office email dated 31.01.2022 (Annexure-III), to discuss the same.

b) The tripping events are based on the daily reports at SRLDC website https://www.srldc.in/DailyReport.aspx under the menu: Reports->Daily-> "TL under Forced Outage".


Deliberations:

4.2.1 The tripping incidents of the transmission elements under forced outages, for which the constituents have to furnish remedial measures taken, were circulated vide mail dated 20.01.2022(Annexure-D). The Constituents were requested to take appropriate action and to furnish specific remedial measures/ action taken covering one or the other items from the following indicative list in time, so as to forward the same to Central Electricity Authority:

➢ Brief details of line patrolling carried out (with tower location). ➢ Brief details of RoW maintenance (by proper Tree-cutting) resorted to. ➢ De-capped insulators replacement. ➢ DC earth fault removal. ➢ PLCC cards replacement. ➢ Relay settings modification. ➢ Steps taken to put A/R or CB into service after they have been locked-out. ➢ Faulty equipment replacement. ➢ Reference to OEM in case of equipment failure. ➢ Brief Details of tests carried out to ascertain the healthiness of various

equipment (Power Transformer/ Reactors/ Surge Arrestors/ Circuit Breakers/ CTs/ PTs/CVTs), like Insulation Resistance (IR) test, Winding Resistance test, Capacitance test, Tan delta test, DGA test, Leakage current test, CRM/ DCRM test, etc.

➢ Any other appropriate remedial measure.

4.2.2 It was informed that the list of tripping events in SR Grid (PRM files in Excel format) are regularly circulated. All constituents were requested to arrange for the regular updates on the remedial measures/action taken, on circulation of the file. The Constituents were once again requested to update the remedial measures taken for transmission elements under forced outages as listed at Annexure-D by 05.03.2022.

4.3. Certificate for Healthiness of Batteries

Agenda:

a) As per the MoP direction, given in pursuant to recommendations of the Enquiry Committee (NEW grid disturbance on 30th& 31st July, 2012), the monthly certificate for healthiness of batteries, installed at 220 KV and above voltage level Substations (for power supply to Relays, RTUs and PLCC equipment) are required to be obtained by RPCs, from their respective Constituents and furnish the same to CEA/ MoP.

b) With reference to above, the Constituents have been requested to submit the certificate on healthiness of batteries on monthly basis (i.e. status for a month shall be sent by the 7th day of the following month) to SRPC Secretariat.

c) The sought status for the month of November, 2021 –January 2022 is awaited from the following SR-Constituents:

Month Utility Name

November, 2021 MEPL

December 2021 NPCIL-MAPS, KKNPP, NTPL

January 2022 APGENCO (Hydro), APTRANSCO, TSGENCO(Hydro), TSTRANSCO, KPCL, KPTCL, TANGEDCO(NCTPS), TANTRANSCO, KSEBL, PED, NTPC-KYMKLM, KKNPP, NTECL, UPCL, NTPL, TPCIL, SEL, MEPL


• The non-reporting of status of healthiness of batteries may be discussed.

Deliberations: 4.3.1 Status of Certificate of healthiness of Batteries was discussed in the meeting and it

was noted that the sought information for the month of December and January 2021 was not received from the following SR-constituents.

Month Utility Name

December 2021 MEPL

January 2022 APTRANSCO, KPTCL, NLCIL, SEL, MEPL

4.3.2 The above constituents were requested to submit the status urgently. The Constituents were once again requested to submit the certificate on healthiness of batteries consistently on monthly basis, by first week of the succeeding month, to SRPC Secretariat.

5. Islanding Schemes (IS) of Southern Region

5.1 Implementation Status

Agenda:

a) In pursuance of MoP directions given in the meeting held on 28.12.2020, SRPC initiated the review & finalization of all In-Service Islanding Schemes (Hyderabad IS, Chennai IS, Neyveli IS &Kudankulam IS) and Under-Implementation Islanding Scheme [Visakhapatnam (Simhadri IS)] in January, 2021, and design of a new Islanding Scheme for Bengaluru metropolitan area in February, 2021.

b) Further, in pursuance of MoP directions given in the meeting held on 31.03.2021, a meeting was conducted by SRPC on 15.04.2021 with all SR Utilities to identify all major cities (with population greater than one million as per Census-2011), and important sites of Defence installations in SR so that the same can be covered either in one of the existing Islanding schemes or by devising new Islanding Schemes. In this meeting, a new Islanding Scheme, viz., Vijayawada IS was identified for implementation.

c) As a result of the comprehensive exercise of review of operational Islanding Schemes and finalization of new Islanding Schemes undertaken during February – August, 2021, all Islanding Schemes (operational as well as new) of SR are under various stages of implementation as given below (Status as on 10 January 2022):

SN Name of the

Islanding

Scheme (IS)

Operational

IS/ New IS

Status of

Implementation

Implementing

Utilities

Utilities from whom

Implementation

PENDING

1 Hyderabad

(Ramagundam)

IS

(Telangana)

Operational IS Review: Completed

on 05.03.2021.

Reviewed Scheme

put into service in

July, 2021.

TSTRANSCO,

TSGENCO,

PGCIL (SR-I),

NTPC-

Ramagundam

---

2 Chennai IS

(Tamil Nadu)


on 18.05.2021

TANTRANSCO,

PGCIL (SR-II)

TANTRANSCO:

Completed for all

boundary elements;


Target Date for

Implementation:

Original:

December, 2021

Revised: February,

2022

pending for 6 out of 47

elements within the

Island. Sought time

extension up to

February, 2022

3 Neyveli IS

(Tamil Nadu,

Kerala)


on 04.06.2021

Reviewed Scheme

put into service in

November, 2021.

TANTRANSCO,

PGCIL (SR-II),

NLCIL, NNTPS,

KSEBL

TANTRANSCO:

Completed for all

elements except one

feeder; however

stated that Islanding

would be achieved due

to implementation of

the tripping at the

other end of the said

feeder

4 Kudankulam IS

(Tamil Nadu,

Kerala)


on 18.08.2021

Target Date for

Implementation:

Original:

December, 2021

Reviewed Scheme

put into service in

December, 2021.

TANTRANSCO,

PGCIL (SR-II),

KSEBL,

TANTRANSCO:

Completed for all

elements except one

feeder; however

stated that Islanding

would be achieved due

to implementation of

the tripping at the

other end of the said

feeder

5 Visakhapatnam

IS

(Andhra

Pradesh)

New IS Design: Completed

on 27.04.2021

The finalized

Scheme put into

service in July,

2021.

APTRANSCO,

APGENCO,

PGCIL (SR-I),

NTPC-Simhadri,

---

6 Vijayawada IS

(Andhra

Pradesh)


on 16.07.2021

The finalized

Scheme put into

service in

November, 2021.

APTRANSCO,

APGENCO,

PGCIL (SR-I),

TSGENCO,

TSTRANSCO

TSGENCO &

TSTRANSCO

7 Bengaluru IS

(Karnataka)


on 15.07.2021

Design: Completed

on 15.07.2021

Target Date for

Implementation:

Original:

KPCL, NTPC-

Kudgi, NTPC-

Talcher (Stage-

II), UPCL, KPTCL,

PGCIL (SR-I) &

PGCIL (SR-II)

NTPC-Kudgi, NTPC-

Talcher (Stage-II),

UPCL & PGCIL (SR-I)


December, 2021

Revised: January,

2022

d) Status of implementation of Chennai, Kudankulam and Bengaluru Islanding schemes would be discussed in the meeting.

Concerned Utilities shall present the latest status in this regard.

Deliberations:

5.1.1 The status of implementation of Islanding scheme was discussed in meeting. The updated status of implementation of various islanding schemes in SR is given below:

SN Name of the

Islanding Scheme

(IS)

Operational

IS/ New IS

Status of

Implementation

Implementing

Utilities

Utilities from whom

Implementation PENDING

1 Hyderabad

(Ramagundam) IS

(Telangana)

Operational

IS

Review: Completed

on 05.03.2021.

Reviewed Scheme

put into service in

July, 2021.

TSTRANSCO,

TSGENCO,

PGCIL (SR-I),

NTPC-

Ramagundam

---

2 Chennai IS

(Tamil Nadu)

Operational

IS

Review: Completed

on 18.05.2021

Target Date for

Implementation:

Original:

December, 2021

Revised: February,

2022

TANTRANSCO,

PGCIL (SR-II)

TANTRANSCO: Completed

for all boundary elements;

pending for 2 out of 47

elements within the Island.

Sought time extension up to

February, 2022

3 Neyveli IS

(Tamil Nadu,

Kerala)

Operational

IS

Review: Completed

on 04.06.2021

Reviewed Scheme

put into service in

November, 2021.

TANTRANSCO,

PGCIL (SR-II),

NLCIL, NNPTPS,

KSEBL


for all elements except one

feeder; however, stated that

Islanding would be achieved

due to implementation of

the tripping at the other end

of the said feeder.


February, 2022

4 Kudankulam IS

(Tamil Nadu,

Kerala)

Operational

IS

Review: Completed

on 18.08.2021

Target Date for

Implementation:

Original:

December, 2021

Reviewed Scheme

put into service in

TANTRANSCO,

PGCIL (SR-II),

KSEBL


for all elements except one

feeder; however, stated that

Islanding would be achieved

due to implementation of

the tripping at the other end

of the said feeder.


February, 2022


December, 2021.

5 Visakhapatnam IS

(Andhra Pradesh)


on 27.04.2021

The finalized

Scheme put into

service in July,

2021.

APTRANSCO,

APGENCO,

PGCIL (SR-I),

NTPC-Simhadri,

---

6 Vijayawada IS

(Andhra Pradesh)


on 16.07.2021

The finalized

Scheme put into

service in

November, 2021.

APTRANSCO,

APGENCO,

PGCIL (SR-I),

TSGENCO,

TSTRANSCO

Confirmation regarding

implementation of IS

pending from TSGENCO &

TSTRANSCO

7 Bengaluru IS

(Karnataka)


on 15.07.2021

Target Date for

Implementation:

Original:

December, 2021

Revised: February,

2022

KPCL, NTPC-

Kudgi, NTPC-

Talcher (Stage-

II), UPCL, KPTCL,

PGCIL (SR-I) &

PGCIL (SR-II)

NTPC-Kudgi informed that

implementation will be

completed by February end.

In the meeting,

Implementation from their

respective ends was

confirmed by NTPC-Talcher

and PGCIL-SR-1.

5.1.2 TANTRANSCO, TSGENCO and NTPC-Kudgi were requested to confirm completion of works at their end for respective islanding schemes and intimate the same to SRPC.

5.2 Creation of SCADA Display to Monitor Vital Parameters of the Island

Agenda:

a) Since formation of an Island can take place at any time, monitoring of the following vital parameters, which have a significant effect on successful Island formation, is of paramount interest:

➢ Anticipated/ actual Generation within the electrical boundary of the Island ➢ Anticipated/ actual Load within the electrical boundary of the Island ➢ Voltage, Frequency & Power Flows along the peripheral lines which are required to

be tripped to form the Island ➢ Details & Flows on the feeders & loads of various AUFR &df/dt stages present

within the Island ➢ Details & Flows on various RE feeders present within the Island.

These parameters are to be monitored in real-time basis in the Control/ Despatch Centre of the area by creating a dedicated page specific to the Islanding Scheme in the SCADA display. To accomplish this, provision should also be made, if required, for installing adequate measuring instruments (like PMUs) at suitable locations within the Island.

b) The above is a mandatory requirement specified by the Ministry of Power (MoP), Government of India, and the action in this regard is time-bound as given below:


Timeline for making available sought SCADA Display

Implementing Utility

Implementation Status as in January, 2022

Hyderabad IS Original: November, 2021

TS-SLDC Completed in November, 2021 (IS Frequency shall also be shown)

Chennai IS Original: December, 2021 Revised: ???

TN-SLDC (Chennai LDC)

Pending

Neyveli IS Original: December, 2021 Revised: ???

TN-SLDC (Erode LDC)

Pending

Kudankulam IS Original: December, 2021 Revised: ???

SRLDC in coordination with TN-SLDC (Madurai LDC) & Kerala-SLDC

Pending

Visakhapatnam IS Original: November, 2021

AP-SLDC Completed in November, 2021 (IS Frequency shall also be shown)

Vijayawada IS Original: November, 2021

AP-SLDC Completed in November, 2021 (IS Frequency shall also be shown)

Bengaluru IS Original: December, 2021 Revised: ???

KA-SLDC Pending

c) All implementing Utilities are requested to furnish Status of implementation along with SCADA Display snapshots by 10.02.2021.

The status of implementation of SCADA Display to Monitor Vital Parameters of Island would be discussed in the meeting.

Deliberations:

5.2.1 The status of creation of SCADA display was discussed in meeting and updated status is given below:

Timeline for making available sought SCADA Display

Implementing Utility

Implementation Status as in January, 2022 (pending Remarks)

Hyderabad IS Original: November, 2021

TS-SLDC Completed in November, 2021 (TS-SLDC was asked to change names such as surviving with participating in Geo Map furnished)

Chennai IS Original: December, 2021 Revised:

TN-SLDC (Chennai LDC)

Completed. (TN-SLDC was requested to display a Tab of list of Islanding forming elements on main page)

Neyveli IS Original: December, 2021 Revised:

TN-SLDC (Erode LDC)

Completed. (TN-SLDC was requested to display a Tab of list of Islanding forming elements on main page.)


Kudankulam IS Original: December,

2021 Revised: February/ March, 2022

SRLDC in coordination with TN-SLDC (Madurai LDC) & Kerala-SLDC

Completed by TN & KL for their respective portions. (TN & KL were asked to check and provide for a Tab of list of Islanding forming elements on main page.) (TN-SLDC and KSEBL had completed respective SCADA display). (SRLDC was requested to complete integration of individual SCADA displays and furnish the complete display by Feb/ March, 2022)

Visakhapatnam IS Original: November, 2021

AP-SLDC Completed in November, 2021 (IS Frequency shall be shown)

Vijayawada IS Original: November, 2021

AP-SLDC Completed in November, 2021 (IS Frequency shall be shown)

Bengaluru IS Original: December, 2021 Revised: February/ March, 2022

KA-SLDC Under Progress. (KA-SLDC was requested to submit complete snapshot of all pages and attend the various observations w.r.to Bengaluru IS SCADA display including the following:

• Islanding forming Elements Tab missing on Main Page;

• Set Frequency is not 47.8 but 47.9 Hz;

• Quantum for AUFR and df/dt stages shall also be shown on respective Tabs on the Main Page)

5.2.2 All implementing Utilities, which were to complete SCADA display works, were requested to attend to the Island specific comments, and furnish the snapshots of the Island in all its detail (i.e., covering Main Page as well as all Tabs details) completed SCADA snapshots by 05.03.2022.

5.3 Revision of U/f & O/f Settings of Participating Generators of various Islanding

Schemes of Southern Region

Agenda:

a) W.r.t. the requirement of all Participating Generators to support Island stabilization, it was explained in various Island meetings and PCSC & OCC meetings that since the Power Number of an Island post its formation would be very small, frequency excursions in the range of 47.5 – 52 Hz could be expected immediately after the Island’s formation. Therefore, it is highly desirable & essential that all participating generators extend support


(cling on to the grid) in this frequency range while the Island is on the course to stabilization.

b) For this, it was stated that the Under-frequency and Over-frequency settings of all participating generators needed to be revised appropriately to ensure that no tripping of participating generator units takes place in the frequency range 47.5 – 52 Hz. It was also informed that at these U/F or O/F tripping frequencies, generators shall not be configured for instantaneous tripping; instead, a suitable time delay, say 500 ms, is needed to be adopted to extend the support required for the stabilization of the Island post its formation. Further, it was also clarified that in case of more no. of generating Units at a particular station (which is usually the case), combination of graded frequency (in steps of 0.25 Hz in the range 46.5 ~ 47.5 Hz; in steps of 0.25 Hz in the range 52.0 – 53.0 Hz) and graded time (in steps of 1 sec in the range 2 ~ 5 sec) tripping of those Units could be employed to ensure that they trip one at a time, if conditions so warrant.

c) In this connection, all participating generators were requested to revise their Unit-wise Under frequency (U/f) and Over frequency (O/f) settings appropriately, and furnish the same to SRPC Secretariat for concurrence. Based on the details furnished so far, a consolidated list of Participating Generators (arranged Islanding Scheme wise) and their communicated U/f & O/f Settings, along with SRPC Remarks indicating their orderliness, had been furnished to concerned Utilities vide SRPC mail dated 24.11.2021 and 21.01.2022. It was requested to take appropriate action for the entries shown in ORANGE & RED colour as indicated therein.

d) In this regard, it was also informed that for each Islanding scheme, for all state sector participating generators (hydro & gas & thermal), the respective Genco has to get the appropriately revised O/f & U/f frequency settings implemented at their generating stations. Similarly, for participating IPP’s, the respective Transco has to get the appropriately revised O/f & U/f frequency settings implemented. For Central sector generating stations, concerned generating stations have to get the appropriately revised O/f & U/f frequency settings implemented at their respective generating stations.

e) It is requested from the Entities responsible for implementing/ coordinating the implementation of revised U/f & O/f settings to take necessary action for the ORANGE and YELLOW entries, which basically involves implementing appropriately revised U/f & O/f settings as per the general principle outlined at Para No.(b) above. In this regard, it was also clarified that SRPC Secretariat has no specific recommendation w.r.t. ORANGE and RED colour entries in the Excel file circulated, and the Entities are free to decide those settings with the condition that they shall be in accordance with the general principle outlined at Para No. (b) above (Attention may please be given to employ graded frequency & graded time settings properly).

f) Under frequency/ Over frequency settings of following generators were not furnished/ not found to be in line with the general principle outlined at Para No.(b) above.

Islanding Scheme (IS)

Utilities responsible for revising UF & OF Settings

Utilities who are yet to confirm appropriate revision of UF & OF Settings

Hyderabad IS

TSTRANSCO, TSGENCO, NTPC-Ramagundam

TSGENCO – KTPP V

Chennai IS

TANGEDCO, TANTRANSCO, NTECL-Vallur, NPCIL-MAPS,

TANGEDCO – NCTPS-I NPCIL-MAPS TANTRANSCO IPPs – [ARS ,Kaveri ,TCPL1-IPP ,TULSYAN1-IPP ,HITEC ,BHATIYA ,CPCL, OPG ALM-IPP]

Neyveli IS TANGEDCO, NLCIL, NNTPS, TANGEDCO – [Sholayar I Unit 1 - 2, KUNDAH 21 110,


TANTRANSCO

KUNDAH32 230, BHAVANI SAGAR PH, KADMPRI2 230, Aliyar PH] NLCIL – [NEYVELI II EXP] NNTPP TANTRANSCO IPPs – [ILFS 400, ABAN1 110, MALCO1 110, CHEMMAST SANMAR (OTH) (RC Plant)]

Kudankulam IS

TANGEDCO, TANTRANSCO, KSEBL, NPCIL-KNPP, NTPL

NTPL TANTRANSCO IPPs – [COASTAL ENERGY, PIONEER,INDIA CEMENTS, THALAYUTHU, SEDCO, MMS NMM [P], KKPL,OPG (P), SAHELI, AUROBINDO, KALAYARKOIL, SAI REGENCY (P), CORAMANDEL, RAMNAD, KOTHARI SUGARS, POOVALUR,TNPL ,RAJ KUMAR (B), VV TITANIUM, KOTHARI SUGARS, SATHAMANGALAM, DALMIA, ARIYALUR, DHANALAKSHMI SRINIVASAN SUGARS, PERAMBALUR SUGAR MILL ERAIYUR, MONDIPATTY TNPL, KOILKALLAPPAL, PPN (CPP), PAPANASAM]

Visakhapatnam IS

APGENCO, APTRANSCO, NTPC-Simhadri

NTPC-Simhadri APTRANSCO IPPs – [Vijeswaram-1 ,Vijeswaram-2 ,Godavari Gas Jegurupadu) ,Sarda Co-gen ,Girija Co-gen ,Machkund ,RCL ,Hinduja TPS ]

Vijayawada IS

APGENCO, APTRANSCO, TSGENCO, TSTRTANSCO

APGENCO- [Dr. NTTPS, VTPS 400KV]

APTRANSCO IPPS- [LANCO 220KV, LANCO 400KV stage-2]

Bengaluru IS

KPCL, KPTCL, NTPC-Talcher-II, NPCIL-Kaiga, UPCL

NPCIL (Kaiga)

g) All concerned Utilities are requested to furnish the appropriately revised U/f & O/f settings by 10.02.2022 so that the same can be freezed in the forthcoming PCSC-100 meeting.

Deliberations: 5.3.1 Under frequency/ Over frequency settings of following generators which were not

furnished/ not found to be in line with the general principle issued by SRPC were discussed in the meeting.


Utilities responsible for revising UF & OF Settings

Utilities who are yet to confirm appropriate revision of UF & OF Settings (in respect of the entities mentioned alongside)

Hyderabad IS

TSTRANSCO, TSGENCO, NTPC-Ramagundam

TSGENCO – KTPP V

Chennai IS

TANGEDCO, TANTRANSCO, NTECL-Vallur, NPCIL-MAPS,

TANGEDCO – NCTPS-I NPCIL-MAPS TANTRANSCO IPPs – [ARS ,Kaveri ,TCPL1-IPP, TULSYAN1-IPP, HITEC, BHATIYA, CPCL, OPG ALM-IPP]

Neyveli IS

TANGEDCO, NLCIL, NNTPS, TANTRANSCO

TANGEDCO – [Sholayar I Unit 1 - 2, KUNDAH 21 110, KUNDAH32 230, BHAVANI SAGAR PH, KADMPRI2 230, Aliyar PH] NLCIL – [NEYVELI II EXP] NNTPP TANTRANSCO IPPs – [ILFS 400, ABAN1 110, MALCO1 110, CHEMMAST SANMAR (OTH) (RC Plant)]

Kudankulam IS

TANGEDCO, TANTRANSCO, KSEBL, NPCIL-KNPP, NTPL

NTPL TANTRANSCO IPPs – [COASTAL ENERGY, PIONEER,INDIA CEMENTS, THALAYUTHU, SEDCO, MMS NMM [P], KKPL,OPG (P), SAHELI, AUROBINDO, KALAYARKOIL, SAI REGENCY (P), CORAMANDEL, RAMNAD, KOTHARI


SUGARS, POOVALUR,TNPL ,RAJ KUMAR (B), VV TITANIUM, KOTHARI SUGARS, SATHAMANGALAM, DALMIA, ARIYALUR, DHANALAKSHMI SRINIVASAN SUGARS, PERAMBALUR SUGAR MILL ERAIYUR, MONDIPATTY TNPL, KOILKALLAPPAL, PPN (CPP), PAPANASAM]

Visakhapatnam IS

APGENCO, APTRANSCO, NTPC-Simhadri

NTPC-Simhadri APTRANSCO IPPs – [Vijeswaram-1 ,Vijeswaram-2 ,Godavari Gas Jegurupadu) ,Sarda Co-gen ,Girija Co-gen ,Machkund ,RCL ,Hinduja TPS ]

Vijayawada IS

APGENCO, APTRANSCO, TSGENCO, TSTRTANSCO

APGENCO- [Dr. NTTPS, VTPS 400KV]

APTRANSCO IPPS- [LANCO 220KV, LANCO 400KV stage-2]

Bengaluru IS

KPCL, KPTCL, NTPC-Talcher-II, NPCIL-Kaiga, UPCL

NPCIL (Kaiga)

5.3.2 All Utilities as mentioned above were asked to take steps to urgently revise the U/F & O/F

settings appropriately in line with SRPC guidelines, and furnish the same for concurrence to SRPC Secretariat latest by 05.03.2022.

5.4 Furnishing of Monthly Certificate on Healthiness of Islanding Schemes by

Generators/ Transmission Utilities / SLDCs/ DISCOMS

Agenda:

a) It is essential to ensure healthiness of relays, communication channel and other equipment instrumental/ involved in forming &establishing the Island, since an Islanding Scheme in place is expected to come to rescue the electrical grid from being totally blacked out during a major grid disturbance. In this regard, CEA directed RPCs to collect information on the Healthiness of Islanding Schemes on monthly basis as per the prescribed formats from all concerned Utilities.

b) All Constituents as listed below were requested to submit certificate on Healthiness of Islanding Schemes on monthly basis –by the first week of every month (i.e. status for a month shall be sent before the 3rd working day of the succeeding month) to SRPC as per the formats, circulated vide SRPC letter dated 09 August, 2021:

Islanding Scheme Constituents

Hyderabad (Ramagundam) IS

TSTRANSCO, SLDC-TSTRANSCO, TSGENCO, PGCIL (SR-I), NTPC-Ramagundam

Chennai IS TANTRANSCO, SLDC-TANTRANSCO, PGCIL (SR-II)

Neyveli IS TANTRANSCO, SLDC-TANTRANSCO, PGCIL (SR-II), PED, NLCIL, NNPTPS, KSEBL

Kudankulam IS TANTRANSCO, SLDC-TANTRANSCO, PGCIL (SR-II), KSEBL

Visakhapatnam (Simhadri) IS

APTRANSCO, SLDC-APTRANSCO, APGENCO, PGCIL (SR-I), NTPC-Simhadri

c) The Certificate of Healthiness of Islanding Schemes for the months of December, 2021 & January, 2022 has not been received from following utilities:


Utilities responsible for maintaining Healthiness

Utilities from whom Healthiness Status awaited for December, 2021

Utilities from whom Healthiness Status awaited for January, 2022

Hyderabad IS TSTRANSCO, TSGENCO, PGCIL (SR-I), PGCIL-SR-I,


NTPC-Ramagundam

TSTRANSCO

Chennai IS TANTRANSCO, PGCIL (SR-II), TN-SLDC (Chennai LDC)

PGCIL-SR-II, TANTRANSCO

Neyveli IS TANTRANSCO, PGCIL (SR-II), PED, NLCIL, NNPTPS, KSEBL

NLCIL PGCIL-SR-II, TANTRANSCO, NLCIL, NNTPP, PED

Kudankulam IS TANTRANSCO, PGCIL (SR-II), KSEBL

PGCIL-SR-II, TANTRANSCO,

Visakhapatnam IS APTRANSCO, APGENCO, PGCIL (SR-I), NTPC-Simhadri,

NTPC-Simhadri, APGENCO

PGCIL-SR-I, NTPC-Simhadri, APGENCO, APTRANSCO

Vijayawada IS APTRANSCO, APGENCO, PGCIL (SR-I), TSGENCO, TSTRANSCO

APGENCO, TSGENCO, APTRANSCO PGCIL (SR-I), TSTRANSCO

d) All utilities concerned are asked to furnish the certificate in the prescribed format regularly (by the 3rd working day of every month) for onward reporting to CEA/ MoP.

Non-compliance in this regard would be discussed in the meeting.

Deliberations: 5.4.1 Non-furnishing of Certificate of Healthiness of Islanding Schemes for the months of

November, December, 2021 and January 2022 was discussed in the meeting. The status is

yet to be received from following utilities:


Utilities responsible for maintaining Healthiness

Utilities from whom Healthiness Status awaited for December, 2021

Utilities from whom Healthiness Status awaited for January, 2022

Hyderabad IS TSTRANSCO, TSGENCO, PGCIL (SR-I), NTPC-Ramagundam

Chennai IS TANTRANSCO, PGCIL (SR-II), TN-SLDC (Chennai LDC)

Neyveli IS TANTRANSCO, PGCIL (SR-II), PED, NLCIL, NNPTPS, KSEBL

NLCIL NLCIL

Kudankulam IS TANTRANSCO, PGCIL (SR-II), KSEBL

Visakhapatnam IS APTRANSCO, APGENCO, PGCIL (SR-I), NTPC-Simhadri

NTPC-Simhadri NTPC-Simhadri

Vijayawada IS APTRANSCO, APGENCO, PGCIL (SR-I), TSGENCO, TSTRANSCO

APGENCO

5.4.2 All Utilities responsible for maintaining Healthiness were requested to furnish the

healthiness of respective islanding schemes in a timely manner.

5.4.3 NLCIL and NTPC-Simhadri were specifically pointed out about submitting the sought

Healthiness Certificate in time since they had not been furnishing the same right from

August, 2021.


6. Protection Management system (PMS) project

6.1. PMS Review Meeting

Agenda:

a) As part of regular PMS review meetings an online meeting of PMS was held on 23.11.2021 by the Executive Committee of the PMS project with PRDC (Project Implementing Agency, PIA) to verify the progress made w.r.t. pending issues of PMS Project, and to assess the readiness of PMS project for being operationalized.

b) TSTRANSCO vide email dated 22.01.2022 had communicated certain observations w.r.to 220kV and 400kV TSTRANSCO network database of PSCT (.mdb file). SRPC has requested Project implementing agency (PIA) to look into the matter.

c) All constituents are requested to consolidate their observations w.r.to PDMS/ PSCT if any and furnish the same on fortnightly/ monthly basis in order to take up the same with PIA.

d) This is for information of the forum.

Deliberations:

6.1.1 SRPC apprised the forum regarding status of PMS project. The following issues were being pursued doggedly with PRDC for operationalizing the Project at an early date:

➢ Performance Issues w.r.t. various Studies (esp. Transient stability studies): Presently transient stability simulation of 10 sec is taking 10 min execution time. And PRDC is being urged to achieve an acceptable metric of 10 sec simulation time in 5 minute execution time.

➢ Verification of the reconfigured AFAS system implemented at 400/230-110 kV Palavady SS of TANTRANSCO: AFAS system was implemented at Palvady SS in 2018, post that many changes had taken place in the substation and hence AFAS system need to be reconfigured. The same was carried out by PRDC in coordination with TANTRANSCO. Verification of the implemented changes needed to be conducted by carrying out by conducting a mini-SAT. Cooperation of TANTRANSCO was also requested for the same.

➢ Closure of huge number of DMNS tickets: Based on the pending DMNS tickets furnished by PRDC, it was observed that some 900 plus Tickets are pending to be closed by PRDC. Since closure of these tickets is essential to ensure accuracy of the PMS Database, Nodal Officers of all SR-Utilities were requested to facilitate PRDC in closing them by providing all requisite details. They were also requested to raise appropriate Tickets (as per stipulated formats) corresponding to Network changes in their respective systems in DMNS promptly after their occurrence.

6.1.2 In this connection, attention of the Nodal Officers was also drawn to SRLDC letter dated 08.02.2022 furnishing their comments relating to many Network Elements that had been recently added to SR-Grid, but missing in PMS Database. All Nodal Officers of concerned Utilities were requested to urgently take steps to raise appropriate DMNS Tickets by providing requisite data so that the missing Network Elements are promptly incorporated in PMS Database by PRDC. It was emphasized that the same is quintessential to that PMS Database reflects the operating condition of SR-Grid all the time.


6.1.3 All constituents were also requested to regularly check the PMS (PDMS & PSCT) Database

for correctness, and furnish their observations, if any, on fortnightly/ monthly basis so that the same can be forwarded to PRDC for their early resolution/ harmonization.

6.2. PMS Nodal Officers Details

Agenda:

a) As part of PMS project, SRPC had collected the details of Nodal Officers of various utilities for all correspondence related to PMS project. Since the PMS project is expected to be operationalised soon, an updated list of nodal officers from each utility is required from all SR constituents for all correspondence related to PMS project Post operationalisation (post Go-Live)

b) The consolidated list of PMS Nodal officers available with SRPC was circulated vide email dated 19.01.2022 for verification and updation if any.

c) Updated details not received from following utilities: APGENCO (except Dr. NTTPS), NTPC-Simhadri, NTPC-Rmgdm, NPCIL-MAPS, NLCIL, UPCL, TPCIL and CEPL.

d) All the above-mentioned utilities are requested to confirm the details urgently before 07.02.2022.

Deliberations:

6.2.1 SRPC informed the forum that details of PMS nodal officers available with SRPC circulated vide email dated 19.01.2022 was not verified by following utilities: NTPC-Ramagundam NPCIL-MAPS, NLCIL, UPCL, TPCIL and CEPL.

6.2.2 All the above utilities were requested to furnish the revised Nodal Officers details.

7. Items for information

7.1. CEA technical Standards

a) CEA has published draft “Central Electricity Authority (Technical Standards for Construction of Electrical Plants and Electric Lines) Regulations, 2021” and draft “Central Electricity Authority (Safety Requirements for Construction, Operation and Maintenance of Electrical Plants and Electric Lines) Regulations (Amendment), 2021” for comments/ suggestions/ objections. Both draft regulations are available on the CEA website www.cea.nic.in. Any comments/ suggestions/ objections shall be sent by post or through e-mail ([email protected]) latest by 14.02.2022.

7.2. Network reconfigurations

The following system strengthening/ new changes have occurred in SR grid:

➢ 1x125 MVAR, 420 kV Bus Reactor along with associated bays at Pugalur 400KV substation under “System strengthening – XXV in Southern Region were put under COD w.e.f 00:00 hours of 22.12.2021 by PGCIL

8. Other Protection Issues, if any, with the permission of the Chair

http://www.cea.nic.in/


9. Sending Agenda items for the PCSC meetings

It is requested that Agenda Items for the PCSC meetings, if any, may please be sent latest by 5th working day of the month to SRPC Secretariat to compile and circulate the same so as to have fruitful discussions in the PCSC meetings.

10. Date of next PCSC meeting

The date of 101st meeting of PCSC will be decided in due course.

*****

SL No Name Email ID

1 N R L K Prasad [email protected]

2 J B LEN [email protected]

3 Betsy Sebastian [email protected]

4 SRPC Secretariat SRPC [email protected]

5 Vamshi reddy [email protected]

6 Ushakar Gudapati [email protected]

7 MS SRPC [email protected]

8 EE/MRT/400KV/Kadapa [email protected]

9 CEE RT KPTCL [email protected]

10 Rajeshwari Bhat [email protected]

11 TSGENCO SAGAR [email protected]

12 SRBPH-APGENCO-ADE/MRT-1 [email protected]

13 ROMEO - Ostrokannada [email protected]

14 EE/MRT/NCTPS1 [email protected]

15 SE TSGENCO [email protected]

16 sbsreenath [email protected]

17 TSGENCO HYDEL [email protected]

18 EE MRT NCTPS2 [email protected]

19 TSGENCO HYDEL [email protected]

20 Assistant Executive Engineer 220KV SY, Srisailam project, [email protected]

21 M sivanaik [email protected]

22 SANTOSH NAIK [email protected]

23 NAGABHUSHANAM [email protected]

24 HPC.ADE7 [email protected]

25 Puilchintala [email protected]

26 Ee/Telecom/Kurnool [email protected]

27 Vamshi SRLDC [email protected]

28 harsha vardhana reddy [email protected]

29 kakanisridhar1969 [email protected]

30 CE P&C TANTRANSCO [email protected]

31 M.Ramachandran CE P&C TANTRANSCO [email protected]

32 EE/Telecom/Rajamundry [email protected]

33 Lower Sileru APGENCO [email protected]

34 ADE MRT NSPH TSGENCO [email protected]

35 ghattaneni veera venkatarao [email protected]

36 Pulichintala HES TSGENCO [email protected]

37 TSTRANSCO AE Vamshi [email protected]

38 Romeo [email protected]

39 Gowri Shankar [email protected]

40 Venkanna Sandupatla [email protected]

41 DYEE/VS/APGENCO [email protected]

42 Linganna, SRBHES, APGENCO [email protected]

43 CE POWER SYSTEM APTRANSCO [email protected]

44 Power system [email protected]

45 Nitish Kumar [email protected]

SRPC Bengaluru

List of Participants of 100th

PCSC Meeting held on 17.02.2022

Page 1 of 3

Annexure-A

mailto:[email protected]



46 malathi [email protected]

47 Executive Engineer/MRT/Atp [email protected]

48 TPS_II_NLC [email protected]

49 Koteswara Rao [email protected]

50 EE MRT ATP [email protected]

51 Anu Ramesh [email protected]

52 CEO, KSPDCL [email protected]

53 ademrtusph [email protected]

54 CEO KSPDCL [email protected]

55 NTPC KUDGI [email protected]

56 devanagowda [email protected]

57 Bindhu M,EE TECH KSEBL [email protected]

58 DEE/MRT/STAGE-IV/RTPP [email protected]

59 NTPC/TSTPS,M Panigrahi [email protected]

60 Nikhitha/SRLDC [email protected]

61 CEE SLDC [email protected]

62 DyEE MRT VTPS [email protected]

63 EE P&C TANTRANSCO VILLUPURAM [email protected]

64 SDSTPS KRPATNAM / M SRINIVASULU DEE MRT [email protected]

65 Senthilkumar Subramanian [email protected]

66 PJHES [email protected]

67 Goodelli Madhukar/SRLDC [email protected]

68 Ae lines nrpm [email protected]

69 TN SLDC [email protected]

70 V R Naidu [email protected]

71 SE TC VSP [email protected]

72 Uday Trivedi [email protected]

73 AEE/M/NRPM [email protected]

74 EE(ODY)BTPS [email protected]

75 sureshkumar [email protected]

76 TSTRANSCO-PRAVEEN-ADE/SYSTEM PROTECTION [email protected]

77 N Amaranath [email protected]

78 APGENCO [email protected]

79 shobana A [email protected]

80 patta suribabu [email protected]

81 Sunil EE Relay Trivandrum [email protected]

82 pratap [email protected]

83 EE/MRT&TRFS/VSP [email protected]

84 Padmakumar [email protected]

85 DEE mrt [email protected]

86 Patteti [email protected]

87 singuru sanjeevarao [email protected]

88 ED SRLDC [email protected]

89 EE Relay Dn Klmsry [email protected]

90 Navin Kumar [email protected]

91 Executive Engineer Auto SS [email protected]

92 KPCLCEED [email protected]

93 KGS, NPCIL [email protected]

94 S.P.Kumar SRLDC [email protected]

95 Vamshi Ballikonda SRLDC [email protected]

96 DEE MRT GWK [email protected]

Page 2 of 3

Annexure-A

97 SRPC Secretariat [email protected]

98 K. Kiran, SR-I [email protected]

99 K. SRIDHAR, EE-TELECOM-APSLDC [email protected]

100 DEE MRT NARNOOR [email protected]

101 Ragunathan K C, GM/NNTPS [email protected]

102 Executive Engineer PMD KSEBL [email protected]

103 Ravi Palivela [email protected]

104 Arthi Sahaya Rones V/SRLDC [email protected]

105 SE/OMC/RAJAHMUNDRY [email protected]

106 Gunasekaran [email protected]

107 EE SLDC MADURAI TNEB [email protected]

108 Executive Engineer PMD [email protected]

109 NPCIL KKNPP [email protected]

110 EE P&C THUDIYALUR [email protected]

111 EEEPC4 [email protected]

112 PGCIL, SRTS II [email protected]

113 subramanyam [email protected]

114 EE RD KSEB KNR [email protected]

115 Jayakumar K.R_ NTPL [email protected]

116 btps [email protected]

117 setelecommunicationsVSKP [email protected]

118 eemrt [email protected]

119 eemrt [email protected]

120 eetelecom kurnool [email protected]

121 D V k R [email protected]

122 deemrt [email protected]

Page 3 of 3

Annexure-A

Grid Occurrences discussed in the 100th Meeting of PCSC held on 17th February 2022 1/58

Analysis of Grid Occurrences – 100

I. A. Details of Grid Disturbances:

Sl No Details of Event Date &Time Reason Generation Loss (MW)

Load Loss

(MW)

Category

1

Complete Outage of 400kV RYTPP Generating Station of APGENCO

09-Dec-2021 23:25 hrs

During antecedent conditions, 400kV Kalikiri - RYTPP Line -1 was under outage. Triggering incident was hand tripping of 400kV Kalikiri - RYTPP Line -2 to contain over voltage at RYTPP end. Since both the lines connected to RYTPP got tripped, this resulted in complete outage of 400kV RYTPP generating station. There was no generation in RYTPP during this event.

0 0 GD-1

SLD:

Station Bus configuration and arrangements at 400kV RYTPP: One and Half breaker scheme

Antecedent conditions: Generating units at RYTPP was under shutdown.

Annexure-B


Connectivity diagram:

Analysis: OVR grading as per SRPC OVR-2021:

Tripping of 400kV Kalikiri - RYTPP line-1: RYTPP (APGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 23:25:27.610 hrs on operation of OVR stage-1 protection (Grading – B, 111%, 9 sec).

Td could not be verified, since corresponding OVR start not available in EL. Kalikiri (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 23:25:27.000 hrs on DT receipt. APGENCO vide report dated 10.02.2022 informed that:

Deliberations:

As per tripping files furnished, in the antecedent condition generating units at 400kV RYTPP were in shutdown. 400kV Kalikiri - RYTPP line-1 tripped at 23:25:27.610 hrs on operation of OVR stage-1 protection at RYTPP end and DT receipt at Kalikiri end.

SRPC enquired about the status of Bus reactors at Chittoor and Hindupur. APTRANSCO informed that 125 MVar Bus reactor would be commissioned at Chittoor by February 2022. They also informed that Hindupur Bus reactor work had not started and the status would be confirmed.

SRLDC informed that a 125MVar Bus reactor at 400kV RYTPP was approved recently.

Annexure-B


APGENCO requested APTRANSCO not to dismantle 220/ 11.5 kV transformer at 400kV RYTPP as the same is necessary for start-up of plant and feeding of auxiliary equipment in the event of complete outage of the 400kV RYTPP SS. SRPC requested APGENCO to sort out the issue in consultation with APTRANSCO.

SRPC pointed out that OVR settings implemented at 400kV RYTPP could not be verified as OVR_start was not configured in EL at 400kV RYTPP and the same shall be configured.

Accordingly, APGENCO was asked to configure OVR_start and OVR_trip in Event logger in order to facilitate

verification of OVR settings at 400kV RYTPP.

2

Complete Outage of 220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS of KPTCL

12-Dec-2021 14:52 hrs

220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS are radially fed from 400kV/220kV Kolar_PG. During antecedent conditions, all poles of Pugalur HVDC were under shutdown. Triggering incident was mal-operation of Pugalur HVDC SPS, while doing a software update in Pugalur HVDC PCs, Immediately, backup protection initiated and SPS operated tripping 220kV Kolar_PG - Kolar_KA Line-1&2 and 220kV Kolar_PG - Chintamani Line-1&2. This resulted in complete outage of 220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS of KPTCL.

0 260 GD-1

SLD:

Annexure-B



Antecedent conditions:

Analysis: Tripping of 220kV Kolar – Chinthamani lines- 1 & 2: Kolar (PGCIL-SR-2) end:

As per FIR/ TR line tripped at 14:52 hrs on operation of Raigarh – Pugalur SPS. Chinthamani (KPTCL) end:

As per FIR/ TR line did not trip at Chinthamani end. Tripping of 220kV Kolar – Kolar_KA lines- 1 & 2: Kolar (PGCIL-SR-2) end:

As per FIR/ TR line tripped at 14:52 hrs on operation of Raigarh – Pugalur SPS. Kolar_KA (KPTCL) end:

As per FIR/ TR line did not trip at Kolar_KA end. As per SRLDC, the details of Load Relief obtained were as follows:

SPS trip signals of Raigarh-Pugalur (RP-1,2 and 3) were triggered at Pugalur HVDC at 14:52 Hrs on 12-12-2021. With respect to the same load shedding details as furnished by respective constituents are given below (as RP-1 is only configured with TK-1 and TK-3):

As it can be observed from the table above load relief is not as per the designed values.

Annexure-B


As per TR, PGCIL-SR2 informed that:

Annexure-B


Remedial Measures Taken as informed by PGCIL-SR-2:

As per KPTCL Report dated 14.02.2022: Pre fault Scenario: Kolar, Chintamani and T.Gollahalli 220kV substations are radially connected to 400 Kolar Powergrid station

through D/c Lines. 220kV Hoody-Malur line was kept open for CB replacement work at Malur end. Hence, Malur, Sarjapur

and VTP 220kV Sub stations were radially fed from Kolar 220kV SS during the incident. Earlier, when HVDC Talcher-Kolar SPS was in service, load relief was provided in the downstream of 400kV

Kolar ICTs in stages for 3 trip signals (TK1, TK2 & TK3). After disarming of Talcher-Kolar SPS, the loads envisaged for TK-1 and TK-3 signal in the downstream of

Kolar ICTs are being used for providing load relief for Raighar-Pugalur SPS signal-1 as detailed below:

On 12.12.2022 at 14.52 Hrs:

It was informed that on 12.12.2021 at 14.52 Hrs, SPS trip signals of Raigargh-Pugalur (RP-1,2 &3) got triggered at Pugalur HVDC at 14:52Hrs which is suspected due to mal operation while updating software, when HVDC poles were under Shut Down condition.

Upon receipt of RP-1 signal at 400kV Kolar Powergrid Station, 220kV lines Kolar 1&2 and Chintamani-1 &2 lines got tripped resulting in complete outage of Kolar and Chintamani, Malur, sarjapura and VTP Substations

Load relief obtained during the incident was 255MW;

(Load relief by Kolar SS is 224 MW including downstream loads of Kolar, Malur, sarjapura and VTP

Substations. Load relief by Chintamani SS is 31MW )

Complete outage to 220kV Malur, Sarjapura and VTP SS was due to non-availability of Hoody source to 220kV Malur SS as Malur-Hoody line was kept open for Circuit Breaker replacement work at 220kV Malur station.

The desired load relief was 337MW from Karnataka. Upon verification regarding less load relief during the incident, it is observed that approximately 85 MW of load in the downstream of 220kV Kolar Substation is now shifted to the newly commissioned 220kV T. Gollahalli substation.

220kV Kolar along with downstream stations and Chintamani SS restored at 15:25Hrs. Remedial Measures to be taken as informed by KPTCL:

In order to get the desired load relief from Karnataka for RP-1 SPS signal, tripping needs to be extended to 220kV T Gollahalli 1&2 lines at Kolar Powergrid substation end in addition to the existing 220kV Kolar-1 &2 and Chintamani 1&2 lines. Powergrid has been requested in this regard.

Annexure-B


Deliberations:

As per tripping report of PGCIL-SR2, in the antecedent condition all 4 poles of ±800kV Raigarh – Pugalur HVDC was under shutdown and update of system computers by OEM was under progress. During the update all protection computers got shutdown simultaneously in pole – 1, 2, 3 & 4.

When both protection computers were lost, backup trip got generated as per existing SPS logic at Pugalur HVDC SS. Absence of both pole protection computers initiated the backup protection trip in all poles and in turn generated emergency stop/protection trip.

As per SPS logic, protection trip of all poles triggered all 3 SPS signals without checking power flow. This triggered generation of all SPS Trip Signals at 14:52Hrs (RP-1, RP-2 & RP-3) tripping 220kV Kolar_PG -Kolar_KA Line-1 & 2 and 220kV Kolar_PG - Chintamani Line-1 & 2. This resulted in complete outage of 220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS of KPTCL as they were radially fed from Kolar-PG.

KPTCL informed that during the incidence 220kV Malur, 220kV Sarjapur and 220kV VTP Sub stations were radially fed from 220kV Kolar SS during the incident and hence there was complete outage.

KPTCL also informed that designed load relief for RP-1 signal could not be obtained due to shifting of approximately 85 MW of load in the downstream of 220kV Kolar Substation to the newly commissioned 220kV T. Gollahalli substation. Hence, they requested PGCIL (SR-2) to extend RP-1 trip to 220kV T. Gollahalli substation as well, for obtaining designed load relief from Karnataka. They requested PGCIL (SR-2) to trip 220kV Kolar- T.Golahhalli lines -1 & 2 in case of operation of RP-1 SPS.

PGCIL (SR-2) informed that in order to take care of such eventualities resulting in operation of RP SPS, the scheme had been modified in consultation with SRLDC. New scheme would be generating SPS signal only if there is any loss of power. The modified scheme would be put into service by February 2022.

Remedial Measures Taken:

PGCIL-SR-2 informed that RP SPS logic was modified in consultation with SRLDC (logic given below) and the new scheme will be implemented by February 2022.

In this connection, PGCIL (SR-2) was asked to extend RP-1 trip signal to open the breakers at Kolar end of

220kV Kolar_PG – T.Golahalli line as requested by KPTCL in order to obtain designed load relief for RP-1 SPS.

In this regard, it was pointed out to SRLDC that since the subject trippings are a result of designed SPS operation, station outages on account of the same need not be reckoned as GD; and this factor may be duly taken into account in future.

Annexure-B


3

Complete Outage of 220kV Kadra PH, 220kV Kodasalli PH of KPCL and 220kV/110kV Karwar SS of KPTCL

26-Dec-2021 08:56 hrs

During antecedent conditions, 220 kV Kaiga-Kadra and 220 kV Kaiga-Kodsalli were in idle charged condition. As per the report submitted, Y-phase pole discrepancy relay operated while de-synchronising Unit-2 at Kodasally. At the same time, Unit-1 LBB operated and all the elements connected to 220kV Bus got tripped. This resulted in complete outage of 220kV Kadra PH, 220kV Kodasalli PH of KPCL. This also resulted in complete outage of 220kV/110kV Karwar SS due to incoming supply failure from 220kV Kodsalli PH.

40 40 GD-1

Installed capacity:

Kadra PH: 150 (3x50) MW

Kodasalli PH: 120 (3x40) MW

SLD:


Annexure-B


Station Bus configuration and arrangements:

Single Bus configuration Antecedent conditions: @Kodasalli PH: @Kadra PH @Nagjhari PH Unit- 1:- 40MW, Unit-1, 2 & 3- Open condition NKS-1 &2 – CB was in Unit-2 & 3:- S/D Kodasalli line: 38MW closed condition NKS-1 line: 1 MW Karwar- 1 & 2 line- 19MW each. NKS-2 line: 1 MW Kaiga line- Open @ kaiga end Kadra line:- 38MW Kaiga line: Open @ Kaiga end Analysis: Tripping of 220kV Kadra – Kodasalli line: Kodasalli (KPCL) end:

As per FIR line tripped at 08:56 hrs on operation of LBB protection.

As per DR line tripped at 08:55:29.997 hrs on B-E fault due to operation of DPR Zone-4. (Td=0)

No LBB signal observed. Kadra (KPCL) end:

As per FIR/ DR/ EL/ TR line did not trip at Kadra end, but 220kV bus became dead at Kadra due to tripping of 220kV Kadra – Kodasalli line at Kodasalli end.

As per DR Zone-2 signal observed. Tripping of 220kV Kodasalli- Nagjheri line: Nagjheri (KPCL) end:

As per FIR/ DR line did not trip at Nagjheri end. Kodasalli (KPCL) end:

As per FIR line tripped at 08:56 hrs on operation of LBB protection.

As per DR line tripped at 08:55:29.997 hrs on B-E fault due to operation of DPR Zone-4 . (Td=0)

No LBB signal observed. Complete outage of 220kV Kadra and 220kV Karwar Stations:

As per FIR/ TR, incoming supply to 220kV Kadra and 220kV Karwar Stations failed and hence there was complete outage of these stations.

As per KPCL Report dated 14.02.2022: During Tripping at Kodasalli PH: While desynchronizing of UNIT-2 ‘Y’ Phase pole discrepancy operated & LBB operated, Unit-1 LBB operated and all the 220kV Kodasalli -Kadra ,Kodasalli- Kaiga,and NKS1/NKS-2 Lines are tripped on LBB .and bus dead @ 08:56 hrs. Unit-2 Master trip Relay(86Z) operated,86B operated, CB Pole discrepancy operated. The external static type relays are in service for LBB protection function.

Annexure-B


Restoration Action taken:

Unit-2 ‘Y’ pole air control valve problem attended & replaced with new one. After clearance from LDC, NKS - 2 line charged from Kodasalli end @ 09:40hrs, Kodasalli -Kadra Line @09:45Hrs, NKS-1 Line @ 9:46hrs, Kodasalli Kaiga line @ 10:47hrs. Reset of all relays annunciation of NKS-1, NKS-2, Kodasalli-Kadra, Kodasalli-Kaiga 220KV line were done.

During Tripping incidence at Kadra PH: At 8:57Hrs, 220KV Kadra- Kodasalli line CB opened @ Kodasalli end due to PD occurred on Unit 2. Bus dead condition occurred. Kadra-Karwar line 1 & 2 in service.

Restoration Action taken:

Opened all C/B of Kaiga, Karwar 1 & 2 lines. informed to LDC and 220KV Karwar. DG set started & CAP charged from DG source. All annunciations reset. @ 9:44 hrs Kadra-Kodasalli line charged from both ends, Bus resumed. @ 9:45 Karwar 1 & 2 lines are charged from our end. Station supply restored on 2 MVA transformer. DG stopped. Kadra-Kodasalli Line charged at 9:44 Hrs from both end. Karwar 1 & 2 lines charged @ 9:45 hrs

Deliberations:

In the antecedent condition, 220kV Kadra-Kaiga and 220kV Kaiga-Kodasalli lines were in idle charged condition (kept open from Kaiga end). There was no generation at 220kV Kadra PH.

It was observed from the tripping files furnished that the triggering incidence for the events was improper CB pole opening while desynchronising Unit-II at Kadra PH. This resulted in LBB protection operation and tripping of 220kV Kadra-Kodasalli and 220kV Kodasalli – Nagjheri lines-1 & 2.

Due to tripping of only grid connected line, bus dead occurred at 220kV Kadra PH and resulted in complete outage of 220kV Kadra and 220/ 110kV Karwar stations.

KPCL informed that CGL breakers at 220kV Kadra PH are very old and hence result in frequent breaker stuck problems. They also clarified that LBB protection implemented at Kadra PH was not configured for any LBB initiation. It checks only current through breaker and breaker opening status.

They also clarified that LBB protection of Unit-II alone operated and all elements tripped as a result of the same. DRs for LBB protection operation could not be furnished as the same was implemented in static relays.

They apprised the forum that all old CGL breakers at Kadra PH would be replaced by ABB breakers under R & U work of the station. Further LBB protection shall also be configured to be initiated only on generation of any protection trip signal. The timeline for completion of the work was stated to be 6 months.

SRPC raised concern over frequent loss of supply to 220/ 110kV Karwar SS as the same serves strategic defence loads. KPTCL informed that during tripping of 220kV Kadra – Karwar line, Defence loads are fed through alternate supply from grid connected 110kV Araga SS. To the query of Member Secretary, KPTCL informed that further network expansion was being planned for Karwar SS. The same was requested to be submitted to SRPC.

Recommendations:

KPCL was requested to change the LBB implementation logic at 220 kV Kadra PH and to trigger LBB operation of CB only if LBB is initiated by a protection trip signal.

Annexure-B


4

Complete Outage of 220kV Gooty _SWS of APTRANSCO

08-Jan-2022 19:46 hrs

As per the report submitted, Y-phase insulator string of 220kV Gooty_SWS Bus-1 got failed and fell on 220kV Boyareddipalli line R-phase Jumper at 220kV Gooty_SWS end. Immediately, BBP of 220kV Bus 1 & 2 operated and all the elements connected to the buses got tripped. This resulted in complete outage of 220kV Gooty_SWS.

0 0 GD-1

SLD:

Annexure-B



Station Bus configuration and arrangements: Double Bus arrangement Bus -1 elements: 220KV Dhone-1, 220KV Gooty RS, 220KV Ananthapur, 220KV BR Palli and ICT-1&3(PGCIL) Bus -2 elements: 220KV Dhone-2, 220KV Gooty RTSS, 220KV Shapuram, 220KV Ultratech and ICT-2 (PGCIL) Antecedent conditions: All elements were in service. Analysis: Tripping of 220/ 400kV ICT-1 & 3 at Gooty (PGCIL-SR-1) :

As per FIR/ DR/ EL/ TR 220/ 400kV ICT-1 &3 tripped on R-Y-E fault at 19:46:30.769 hrs on operation of BBP of Bus-1 at 220kV Gooty SWS.

Tripping of 220/ 400kV ICT-2 at Gooty (PGCIL-SR-1) :

As per FIR/ DR/ EL/ TR 220/ 400kV ICT-2 tripped on R-Y-E fault at 19:46:30.624 hrs on operation of BBP of Bus-2 at 220kV Gooty SWS.

Annexure-B


Complete outage of 220kV Gooty SWS (APTRANSCO) end:

As per FIR/ DR/ EL/ TR all elements connected to 220kV Gooty SWS tripped on R-Y-E fault at 19:46:31.252 hrs on operation of BBP of Bus-1 and Bus-2.

As per TR, APTRANSCO informed that:

As per APTRANSCO report dated 16.02.2022: Description of the Incident:

All the elements connected to the 220kV Bus-2 were tripped initially due to the operation of LBB protection of 220kV Bus-2 and followed by Busbar Protection operation of 220kV Bus-1. All the feeders connected to 220kV Gooty SWS were also tripped at remote ends.

Relay Indications at 220kV SWS, Gooty:

S No Element Indications

1 Central Unit indications (Areva make, Micom P741)

Trip 50BF Zone-2 Trip 87BB Zone-1

2 220kV Ultrateck PU (Areva make, Micom P742)

Trip 50BF(CU)

3 220kV Shapuram PU (Areva make, Micom P742)

Trip 50BF(CU)

4 220kV Gooty RTSS PU (Areva make, Micom P742)

Trip 50BF(CU)

5 220kV Dhone-II PU (Areva make, Micom P743)

Trip 50BF(CU)

6 220kV PGCIL-II PU (Areva make, Micom P742)

Ext.CB Fail, Trip 50BF(CU)

7 220kV Bus Coupler( Both Bus-1 & 2 PUs) (Areva make, Micom P742)

Trip 50BF(CU)

8 220kV Boyareddypalli PU (Areva make, Micom P742)

Trip 87BB

9 220kV Anantapuramu PU (Areva make, Micom P742)

Trip 87BB

10 220kV Gooty RS PU (Areva make, Micom P742)

Trip 87BB

11 220kV Dhone-1 PU (Areva make, Micom P742)

Trip 87BB

12 PGCIL ICT-1 PU (Areva make, Micom P742) Trip 87BB

13 PGCIL ICT-3 PU (Areva make, Micom P743) Trip 87BB

Annexure-B


Relay Indications of feeders at Remote ends due to delayed clearance of the fault: (Connected to Bus-2 at Gooty end)

S No Feeder Relay Indications

1 22okV Boyareddy Palli Zone-2

2 220kV Anantapuramu Zone-2

3 220kV Gooty RS Zone-2

Relay Indications of feeders at Remote ends: (Connected to Bus-II at Gooty SWS end):


1 220kV Gooty RTSS Zone-2

Relay Indications of feeders not connected to 220kV SWS, Gooty:


1 220kV Ragulapadu Zone-2

PMU Plot:

R-Ph fault was started at 19:46:30:840 Hrs and cleared at 19:46:31:240 Hrs (Duration 400mSec).

Detailed Analysis:

The Insulator string in Y-Ph of 220kV Bus-1 was flashed over and the portion of the conductor disconnected from structure and fell to the ground.

For this Bus fault, CT saturation observed in the PUs of 220kV Ananatapuramu, 220kV Gooty RS, 220kV PGCIL ICT-1 IV, 220kV PGCIL ICT –III IV, 220kV Ultrateck, 220kV RTSS,220kV PGCIL ICT- II, 220kV Bus-I PU and 220kV Bus-II PU. This blocks the Bus bar protection for 150mSec, as per the philosophy of the relay.

Meanwhile, External LBB Operated Input was received to PGCIL-II PU (Suspecting that PGCIL end LBB relay was mal-operated), this in turn caused operation of LBB protection of 220kV Bus-2 and tripped all the feeders and PGCIL ICT LV-II at Gooty end.

Remote ends of 220kV Boyareddypalli, 220kV Anantapuramu and 220kV Gooty RTSS, 220kV Gooty RS feeders connected to 220kV Bus-2 of Gooty SWS were tripped on operation of Zone-2 Distance Protection.

220 kV Ragulapadu-Gooty RS was also tripped at Ragulapadu end on Zone-2 Distance protection.

After completion of Blocking period, 220kV Bus-1 Busbar Protection operated clearing the Bus fault.

Annexure-B


Remedial measures taken/Proposed:

APTRANSCO informed the following RM vide report dated 16.02.2022:

The CT Saturation observed in the Busbar relay for less fault current. On 22-01-2022, the relay was tested

and observed delayed operation in the relay. The same was communicated to OEM for recommendations

and OEM response was not satisfactory. Hence the efforts were under progress to arrange for the

deputation of OEM Engineer to the site for rectification of the problem.

The Spurious operation of External LBB operation of PGCIL end PGCIL-II LBB relay was suspected because of

the following issues:

There was no DC earth leak in the 220V DC System at Gooty SWS end.

The armoured Cable connected between External LBB relay at PGCIL ICT-II IV end and to the PU at

APTRANSCO end was found to be healthy.

It was learnt that, the External LBB relay at PGCIL end was not configured for Events recording.

In view of the above, the following were proposed for all the PGCIL ICT-I, II and II:

o To enable Internal LBB function at APTRANSO end PU and to provide the logic as below.

In order to implement the above logic, PGCIL need to provide LBB initiation contacts and hence requested M/s. PGCIL Gooty to provide initiation contacts. They informed that there are no spare contacts available in the relay.

Time coordination of 220kV Ragulapadu- Gooty RS feeder was verified and the Zone-2 time was graded

from 0.3 Sec to 0.6 Sec.

Deliberations:

It was noted that as per tripping files furnished, the triggering incidence for the events was flashover of disc insulator string in Y-ph of 220kV Bus-1 and subsequent falling of the conductor on 220kV Boyareddi palli feeder R-ph take off jumper and on ground.

This resulted in R-Y-E bus fault and operation of BBP of both Buses 1 & 2, tripping all connected elements

External LBB operated

at

PGCIL end

Internal LBB operated

at APTRANSCO end

AND

LBB

Operated

Annexure-B


including 220/ 400kV ICT-1, 2 & 3.

APTRANSCO informed that on the day of incidence, the Insulator string in Y-Ph of 220kV Bus-1 flashed over and a portion of the conductor disconnected from structure and fell to the ground causing Bus-1 fault, but due to CT saturation in PUs of connected element, BBP was blocked for 150msec as per philosophy of relay.

Meanwhile External LBB Operated Input received to PGCIL ICT-II PU and in turn caused operation of LBB protection of 220kV Bus-2 and tripped all the connected elements.

Subsequently, Bus-1 BBP also operated and resulted in complete outage of the SS. It was also informed that all the 220kV lines tripped on distance protection Zone-2 at remote end.

PGCIL-SR-1 pointed out that there was no LBB Operation initiation from PGCIL ICT-II, the spurious high signal might be due to potential rise in the cable as a result of delayed BBP operation. They informed the forum that in order to avoid spurious sending of LBB initiation to 220kV Gooty SW of APTRANSCO, external auxiliary relay is connected between Gooty_PG and Gooty_AP portion.

They also raised the issue of frequent Bus faults at 220kV Gooty SWS. The delayed clearance of the same results in operation of back up protection of PGCIL-SR-1 ICTs.

SRPC enquired regarding the status of regular condition monitoring measures at 220kV Gooty SWs of APTRANSCO and recommended APTRANSCO to ensure healthiness of all equipment, including thermal scanning and other condition monitoring measures in order to avoid frequent Bus faults.

Recommendations:

APTRANSCO to sort out the issue of delayed operation of BBP relay at 220kV Gooty SWS in consultation with OEM and submit a report to SRPC.

5

Complete Outage of 400kV RYTPP Generating Station of APGENCO

12-Jan-2022 22:51 hrs

During antecedent conditions, 400kV Kalikiri RYTPP Line -2 was under outage. Triggering incident was tripping of 400kV Kalikiri RYTPP Line -1 on over voltage stage-1 protection at RYTPP end and DT was received at Kalikiri end. Since both the lines connected to RYTPP got tripped, this resulted in complete outage of 400kV RYTPP generating station. There was no generation in RYTPP during this event.

0 0 GD-1

SLD:

Annexure-B


Station Bus configuration and arrangements at 400kV RYTPP: One and Half breaker scheme

Antecedent conditions: Generating units at RYTPP was under shutdown. Analysis: OVR grading as per SRPC OVR-2021:

Tripping of 400kV Kalikiri RYTPP line-1: RyTPP (APGENCO) end:

As per FIR/ DR/ EL/ TR line tripped at 22:51:04.544 hrs on operation of OVR stage-1 protection (Grading – B, 111%, 9 sec).

Td could not be verified, since corresponding OVR start not available in EL. Kalikiri (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 22:51:04.000 hrs on DT receipt. Remedial Measures Taken: As per APGENCO Report dated 10.02.2022:

Deliberations:

It was observed that as per tripping files furnished, in the antecedent condition generating units at 400kV RYTPP were under shutdown. 400kV Kalikiri - RYTPP line-1 tripped at 22:51:04.544 hrs on operation of OVR stage-1 protection at RYTPP end and on DT receipt at Kalikiri end.

SRPC enquired about the status of Bus reactors at Chittoor and Hindupur. APTRANSCO informed that 125MVar Bus reactor would be commissioned at Chittoor by February 2022. They also informed that Hindupur Bus reactor work was yet to be started and the status would be confirmed.

SRLDC informed that a 125MVar Bus reactor at 400kV RYTPP was approved recently.

APGENCO requested APTRANSCO not to dismantle 220/ 11.5 kV transformer at 400kV RYTPP as the same is necessary for start-up of plant and feeding of auxiliary equipment in the event of complete outage of the 400kV RYTPP SS. SRPC requested APGENCO to sort out the issue in consultation with APTRANSCO.

SRPC pointed out that OVR settings implemented at 400kV RYTPP could not be verified as OVR_start was not configured in EL at 400kV RYTPP and the same shall be configured.

Annexure-B


6

Complete Outage of 220kV Gooty_SWS and Multiple Trippings in 220kV/132kV Gooty_RS of APTRANSCO

20-Jan-2022 20:12 hrs

As per the report submitted, triggering incident was failure of B-ph CT of 220kV Gooty_SWS - Gooty_RS line at 220kV Gooty_RS end. At 200kV/132kV Gooty_RS, 220kV side BBP operated and all the connected elements got tripped. 132kV Gooty_RS was intact during this event. At 220 kV Gooty_SWS, Gooty_RS feeder was not tripped and all the connected source feeders got tripped at remote ends including 400kV/220kV Gooty_PG ICT#1,2, and 3. This resulted in complete outage of 220kV Gooty_SWS.

0 0 GD-1

SLD:


Annexure-B


Station Bus configuration and arrangements at 220kV Gooty SWS: Double Bus arrangement Antecedent conditions:

220kV SWS, Gooty was fed with PGCIL ICT-I, II & III IVs and all the connected feeders are in service. At 220kV Receiving Station, Gooty was connected with Gooty SWS, Gooty RS and Alipura (KPTCL).

Analysis: Tripping of 220kV Gooty SWS – Gooty RS line: Gooty SWS (APTRANSCO) end:

As per FIR, line did not trip.

DR not furnished.

As per EL, line tripped B-E fault at 20:08:38.719 hr due to A/R 3-ph trip operation.

In the EL, Reverse Zone pickup was also observed.

Line Tripped on what protection was not clear from EL.

Time sync issue.

As per TR,

Gooty_RS (APTRANSCO) end:

As per FIR/EL, line tripped at 20:12 hrs on distance protection Zone-3/ Zone-4 operation.

As per DR line tripped at 19:09:22.768 hrs on operation of DPR Zone-1 but B-ph CB did not open and subsequently line tripped after nearly 850msec.

Both Zone-1 and Zone-4 pickup observed.

The operation of LBB protection was not found in the furnished DR & EL. Outage of 220/ 132 kV Gooty-RS of APTRANSCO:

As per FIR/ DR, all elements connected to 220/ 132kV Gooty-RS tripped at 19:29:49.110 hrs on operation of BBP Zone-1.

As per DAT files, 220kV Gooty_RS – Gooty_SWS line did not trip (B-ph Pole) and this led to LBB operation of the CB of 220kV Gooty_RS – Gooty_SWS line at Gooty_RS station after 200msec.

Time sync issue. Tripping of 400/ 220kV ICTs-1, 2 & 3 at Gooty PG (PGCIL-Sr-1) :

As per FIR/ DR/ EL/ TR 400/ 220kV ICTs-1, 2 & 3 tripped at 20:12:28 hrs on operation of Backup overcurrent/ earth fault protection.

Top could not be verified since OCR pick up not in DR/ EL.

Annexure-B


APTRANSCO vide report dated 16.02.2021 informed the following: Detailed Analysis:

B-Ph CT of 220kV Gooty RS-Ragaulapadu feeder was failed because of bursting the CT bottom tank. This caused the operation of 220kV Busbar Protection at Gooty RS and all the connected elements were tripped.

For this fault, on 220kV Gooty SWS-Gooty RS feeder Gooty SWS end Distance protection not operated,

because of failure of fuses of CVT & Bus PT at CVT MB & PT MB respectively. It was found that, there were double earthings in CVT & Bus PT circuits, also fuses were available in Neutral circuit instead of Links and these fuses were blown.

This caused the delayed clearance of the fault at remote ends on all the connected source feeders/elements to 220kV Gooty SWS.

Annexure-B


DR & EL Analysis:

20:12:28:680 mSec : Fault Started After 10mSec : 220kV Busbar Protection Operated at Gooty RS

And tripped all the connected elements.

After 100mSec : As the fault was not cleared and since there is current

in B-Ph CT of 220kV Gooty SWS feeder bay. LBB retrip given.

Annexure-B


After 200mSec : As the fault was not cleared and since there is current

in B-Ph CT of 220kV Gooty SWS feeder bay. LBB backtrip given.

After 350m Sec : 220kV Gooty SWS-Shapuram feeder CB tripped at

Shapuram end on Zone-2 of Distance protection. After 600m Sec : 220kV Gooty SWS-Boyareddypalli feeder CB tripped at

Boyareddypalli end on Zone-3 of Distance protection.

After 760 m Sec : LVs of ICT-I,II & III may be tripped at PGCIL end.

After 800m Sec : 220kV Gooty SWS-Anantapuramu feeder CB tripped at

Anantapuramu end on Zone-3 of Distance protection. After 900m Sec : 220kV Gooty SWS-Dhone-1&2s feeder tripped at

Dhone end on Zone-3 of Distance protection.

PMU Plot:


The Double earthings in line CVT & Bus PT circuits were removed. Links were placed in place of fuses in

neutral circuits.

The failed CT (ABB make, YOM:2005 was replaced with a healthy CT (Areva T&D India Ltd Make,

YOM:2009).

Restoration:

At 20:45 Hrs, 220kV Ragulapadu feeder charged.

At 20:51 Hrs, 160MVA PTR-II HV Charged

At 20:52 Hrs, 160MVA PTR-II LV Charged

At 21:10 Hrs, 220kV RTSS feeder Charged

At 21:10 Hrs, 160MVA PTR-I HV tried for charging but was not successful due to CB mechanical

problem.

On 21/01/22 at 17:26 Hrs, 160MVA PTR-I HV charged after rectification of the CB mechanical problem.

On 21/01/22 at 17:27 Hrs,160MVA PTR-I LV charged.

On 21/01/22 at 20:02 Hrs,B-ph CT of 220kV Gooty SWS feeder replaced and charged from Gooty RS

end.

On 21/01/22 at 20:12 Hrs, 220kV Gooty SWS feeder charged from Gooty SWS end and stood OK.

Deliberations:

It was noted that the triggering incident for the events was B-ph CT blast of 220kV Gooty SWS – Gooty RS line at Gooty_RS end. This led to BBP operation at 220 kV Gooty RS and tripping of all elements at 220kV Gooty_RS.

APTRANSCO clarified that even though two buses are available, due to limitations in obtaining isolator feedback, single zone operation of BBP was enabled at 220kV Gooty RS.

But C-ph pole of CB at Gooty-RS end of 220kV Gooty_RS – Gooty_SWS line did not trip and this led to LBB operation of the CB of 220kV Gooty_RS – Gooty_SWS line at Gooty_RS station after 200msec. But LBB protection was not configured to send DT to Gooty SWS end and fault continued to be fed from that end.

APTRANSCO informed that the Distance relay of 220kV Gooty_RS – Gooty_SWS line at Gooty_SWS end did not detect the fault because of failure of fuses of CVT & Bus PT at CVT MB & PT MB respectively. They informed that during troubleshooting, it was found that in some of the C&R panels, the neutrals of PT & CVT

Annexure-B


circuits were grounded. As per the standard practice the secondary neutrals of CVT and PT were already grounded in the yard and as per old practice the fuses were provided for neutral circuit in CVT and PT MB. The additional grounding in the new C&R panels created double grounding to the PT and CVT secondary circuits in the control room as well as in the yard.

Because of the heavy fault currents that flowed in yard ground due to Bus fault, this high ground current induced circulating currents in the secondary neutral wires of PT & CVT due to double earthing of neutral. The circulating currents caused the neutral fuses in the PTMB and CVT MB to blow out.

APTRANSCO informed that the fault was cleared by tripping of all source feeders at remote end on zone-3/ zone-4 and 400/ 220kV ICT-1, 2 & 3 on Backup overcurrent/ earth fault protection. Hence there was delayed clearance of fault. 132kV side of 220/132 kV Gooty_RS was grid connected and hence, there was no complete outage of 220/ 132 kV Gooty RS.

SRPC informed that 3-ph A/R and reverse zone pick up had been observed at 220kV Gooty SWS end EL of 220kV Gooty_RS – Gooty_SWS line need to be checked by APTRANSCO. Time sync issue at 220kV Gooty RS and 220kV Gooty SWS shall be rectified.

SRPC also pointed out that APTRANSCO shall configure LBB protection to send DT to remote end for speedy clearance of fault.

Recommendations: APTRANSCO to configure LBB protection to send DT to remote end at 220kV Gooty_RS SS. APTRANSCO to attend time-sync issues at their 220kV Gooty RS and 220kV Gooty SWS.

7

Complete Outage of 230/ 110 kV Taramani SS of TANTRANSCO

25-Jan-2022 17:14 hrs

As per the report submitted, triggering incident was operation of 230kV Bus- A and Bus-B BBP while charging 230kV Bus-B at 230kV/110kV Taramani SS. All the feeders connected to 230kV bus bars got tripped and this resulted in complete outage of 230/110kV Taramani SS.

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Annexure-B


Station Bus configuration and arrangements at 230kV/110kV Taramani SS:

Main and auxillary Bus scheme

Analysis:

Annexure-B



TANTRANSCO vide report dated 10.02.2022 informed that the fixed contact of bus selection isolator (BUS A) was replaced with new one on 28.01.2022.

Complete outage of 230/110kV Taramani SS of TANTRANSCO:

As per FIR/ DR/ EL/ TR all elements connected to the SS tripped at 17:14 hrs on operation of BBP of Bus-A.

No BBP operation signal in DR. DR shall be properly configured. Deliberations:

As per tripping files furnished, in the antecedent condition all elements connected to 230/110 kV Taramani SS was connected to 230 kV Bus-A as Bus-B was under LC for maintenance works.

During normalisation of 230 KV Bus-B, after a maintenance work by operation wing, Bus-A isolator switch was opened; heavy arcing had been witnessed in that bay causing R-Y Bus fault. This was due to improper seating of Bus-B isolator switch in 230 kV R.A. Puram feeder.

TANTRANSCO clarified that while normalizing Bus-B after LC, Bus coupler was closed; still there was heavy arcing in Bus-B isolator switch of 230 kV R.A. Puram feeder.

This led to operation of BBP of Bus-A and tripping of all connected elements.

SRPC pointed out that the Bus DR furnished by TANTRANSCO was not configured properly for digital signal legends and the same shall be carried out immediately.

TANTRANSCO informed that the digital signals have been configured on 29.01.2022, post the event. Presently the BBP operation is single zone due to limitation of isolator feedback and the same would be ensured during ongoing up-gradation of SS to 400kV. Timeline for completion of work was stated to be 8 months.

8

Complete Outage of 220kV/132kV Parawada SS of APTRANSCO

28-Jan-2022 06:49 hrs

During antecedent conditions, 220kV/132kV Parawada SS was radially fed from 220kV VSS due to outage of 220kV Parawada Anrak line. As per the report submitted, triggering incident was R-phase jumper failure in 220kV Parawada VSS line and the line got tripped at both the ends on operation of Earth Fault protection. Due to tripping of only connected line, there was complete loss of supply at 220kV/132kV Parawada SS.

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Annexure-B


SLD:

Station Bus configuration and arrangements: Antecedent conditions:

In antecedent conditions 220 KV Parawada SS was getting incoming supply radially from 220kV VSS and the 220kV Parawada-ANRAK feeder was in idle charge condition from 220kV ANRAK end, kept open at 220kV Parawada end.

Annexure-B


Analysis: Tripping of 220kV Parawada – VSS line: VSS (APTRANSCO) end:

As per FIR line tripped at 06:33 hrs on operation of earth fault protection.

As per DR/ EL, line tripped at 06:33:46.389 hrs in B-ph on B_E fault due to operation of DPR Zone-1 but tripped in 3-ph at 06:33:46.685 hrs

Parwada (APTRANSCO) end:

As per FIR/ EL line tripped on B-E fault at 06:39:19.571 hrs

As per FIR there was broken conductor alarm.

What protection operated not clear. However, Distance pick up signal observed.

Time sync issue

DR without any legends. APTRANSCO informed the following vide report dated 16.02.2022: Description of the Incident:

For a fault in 220kV VSS-Parawada, 220kV VSS-Parawada feeder tripped at both ends

Relay Indications at 220kV VSS:

Main-2 relay (REL670): Z-1, R-Ph operated, A/R Blocked. Relay Indications at 220kV SS, Parawada:

Main-1 relay ( P444): Zone-3 Operated.

Annexure-B


PMU Plot:

Reasons for tripping:

MRT wing informed that R-phase Jumper got Cut at Loc 465 and was found hanging in the air towards Parawada end.

It was assumed that the Arc formed due to R-phase fault might have come in the vicinity

of Y-phase jumper resulting in the Y-phase Fault.

Lines wing informed that R-Ph (Bottom Phase) jumper was disconnected towards VSS

end and hanging towards Parawada side, no other fault was found in the line.

DR & EL Analysis:

06:49:12:920 m Sec: R-Ph Fault Started with fault current 34000A. At VSS end, R-Ph Zone-1 Protection operated by the Main-2 relay (REL670) and A/R started.

At Parawada end, as jumper is hanging near to tower and Zone-3 started.

After 540mSec : Y-Ph fault started with fault current 34000A. Accordingly, 3ph trip given at VSS end.

After 600m Sec: Zone-3 trip given at Parawada end after completion of

the Zone-3 time.


Time Synchronization to the relays to be provided at both VSS and Parawada.

Deliberations:

As per tripping files furnished, in the antecedent conditions, 220/ 132KV Parawada SS was radially fed from 220KV VSS but it was connected to 132kV mesh.

The triggering incidence was R-phase jumper failure in 220kV Parawada-VSS line at loc 465. Arc formed due to R-phase fault come in the vicinity of Y-phase jumper resulting in the Y-phase fault.

APTRANSCO informed that the line tripped in Zone-1 at VSS end and in Zone-3 at Parawada end due to 132kV mesh connectivity at Parawada.

Tripping of only grid connected line resulted in complete outage of the SS.

APTRANSCO informed that in order to avoid fault feeding from 132kV side, one more 220kV line was planned for 220kV Parawada SS from 220kV VSS. Work was under progress.

In this connection, APTRANSCO was requested to check the DR labelling at Parawada SS, and to sort out the Time sync issues.

SRPC also requested APTRANSCO to diligently follow condition monitoring measures for all equipment & lines around VSS.

Annexure-B


B. Details of Grid Disturbances of Renewable Energy Stations:

Sl. No.

Details of Event Date &Time Reason

Generation Loss

(MW)

Load Loss

(MW)

Category

1

Complete Outage of 220kV/33kV Ostro Kannada Wind Plant

03-Dec-2021 19:16 hrs

As per the report submitted, triggering incident was tripping of a 33kV feeder at Ostro end due to 3-phase fault. At the same time, 220kV Hiriyur - Ostro Kannada line and 220kV/33kV 160MVA Transformer tripped on suspected mal-operation of Over current relay at Ostro Kannada end. 220kV Hiriyur - Ostro Kannada line was holding at Hiriyur end. Due to tripping of the only connected line, there was complete outage of 220kV/33kV Ostro Kannada Wind Plant.

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SLD: Connectivity diagram:

Station Bus configuration and arrangements: Double Bus scheme

Analysis: Tripping of 220kV Hiriyur –Ostro Kannada line: Hiriyur (PGCIL-SR2) end:

As per SRLDC line did not trip. No tripping files furnished. Ostro Kannada end:

As per FIR line tripped at 19:16 hrs on operation of overcurrent protection.

The O/C relay was non-directional.

Legends to be properly named in DR.

Annexure-B


Deliberations:

It was observed that representatives of Ostro Kannada Wind Plant had not attended the meeting to present the incident.

It was noted from SRLDC report that the triggering incidence for the events was tripping of a 33kV feeder at Ostro end due to 3-phase fault. During the incidence, 220kV Hiriyur - Ostro Kannada line and 220kV/33kV 160MVA Transformer tripped on suspected mal-operation of Over current relay at Ostro Kannada end.

Tripping of only grid connected line resulted in complete outage of 220kV/33kV Ostro Kannada Wind Plant.

Recommendations:

M/s Ostro Kannada to furnish a detailed Report on the subject tripping covering/ explaining the following aspects:

SLD showing the location of the fault.

If the fault was on 33 kV line, the reasons for non-operation of the primary protections on the faulted line.

The reasons for the fault to spread to 220 kV side connecting line when 220 kV/ 33 kV Transformer was there in between.

The reasons for non-operation of transformer backup protections.

Improper labeling of various signals in the DR.

Remedial measures taken.

II. Details of Grid Incidents:

Sl No Details of Event Date &Time Reason Generation Loss (MW)

Load Loss

(MW)

Category

1.

Tripping of 230 kV Bus- 1 & 2 of 400/ 230 kV Kudankulam Nuclear PP of NPCIL

06-Dec-2021 21:41 hrs

As per the report submitted, triggering incident was tripping of all the elements connected to 230kV Bus-1 and 2 of 400kV/230kV Kundankulam Nuclear Generating Station due to operation of 230kV Bus-1 and Bus-2 BBP.

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Installed Capacity: 2x220MW Connectivity diagram:

Annexure-B


SLD:

Station Bus configuration and arrangements at 230kV KKNPP GS: Two Main Bus scheme Antecedent conditions: Following feeders are connected to Bus-A& B before actuation Bus bar protection.

ADA BUS

230KV KKNPP-Tuticorin (ADL31) line.

Reserve Auxiliary Transformer#1(10BCT01&02)

Inter Connecting Transformer#1(ACT10)

ADB BUS

230KV KKNPP-S.R.Pudur(ADL15) line

Reserve Auxiliary Transformer#2(20BCT01&02)

Common Station Auxiliary Transformer (00BCT01)

Inter Connecting Transformer#2(ACT20)

BUS COUPLER (ADQ90) was in closed condition Tripping of 230kV KKNPP – SR Pudur line: KKNPP (NPCIL) end:

As per FIR/ TR line tripped due to Busbar differential protection operation.

As per DR/ EL Z4 start and Toc pick up signal observed. SR Pudur (TANTRANSCO) line:

As per FIR/ TR line was hand tripped at SR Pudur end. Tripping of 230kV KKNPP – TTPS line: KKNPP (NPCIL) end:


As per DR/ EL Z4 start and Toc pick up signal observed. R-E fault observed. TTPS (TANTRANSCO) line:

As per FIR/ TR line was hand tripped at TTPS end.

Annexure-B


Tripping of 400/ 230kV ICT-1 & 2 at KKNPP: KKNPP (NPCIL) end:


As per DR/ EL no protection signal operation observed. As per KKNPP Report dated 15.02.2022: Event Sequence:

On 06.12.2021 at 21:41:38hrs Bus-A (ADA) bus-bar differential protection (87BB) actuated.

At 21:41:41hrs Bus-B (ADB) bus-bar differential protection (87BB) actuated.

KKNPP end ADL15 line circuit breaker (ADL15GS001) closed at 22.32hrs through Bus-B(ADB) and ADL15 S.R.Pudur end CB closed at 22:45hrs and immediately at 22:45:38 hrs Bus-B (ADB) Bus Bar differential protection actuated.

During test charge, flash over light was observed in GIS.

During visual inspection through inspection window it was found that ADL15 (230KV KKNPP-S.R.Pudur) Bus-A disconnector compartment flashover marks were noticed.

Fault Location identification:

By carrying out High-Voltage test (at 5 kV) on 07.12.2022, the fault location for 230 kV Bus-A was identified.

Normalization:

Bus-A (ADA), ADL15 and bus coupler isolated for normalization of 230kV GIS.

On 08.12.2021 Bus-B (ADB) charged through ADL31 transmission line. Subsequently ICT-1&2 synchronized in 400kV GIS.

CSAT, unit-1&2 RAT were charged. Rectification plan:

The 230kV GIS Bus-A disconnector flashover rectification is highly specialised work. This is to be carried out through GIS manufacturer expert.

Deliberations:

As per tripping files furnished, all elements connected to 230kV Bus-A tripped on 06.12.2021 at 21:41:38 hrs. on operation of Bus-A BBP. NPCIL informed that Bus-A BBP operated at 21:41 hrs on operation of Bus-A Bus bar differential protection.

NPCIL informed that BBP of Bus-A operated on Bus-A fault due to flashover in Bus-A disconnector compartment of 230kV KKNPP SR Pudur line.

Immediately Bus-B BBP also operated due to Bus-B fault. It was stated that Bus-B fault was caused due to deposit of melted metal from Bus-A on to Bus-B which resulted in complete outage of 230kV Bus at NPCIL-KKNPP.

NPCIL apprised that charging of 230kV Bus-B was attempted at 22:45 hrs by closing CB of 230kV KKNPP SR Pudur line but it resulted in tripping of Bus-B due to Bus-B BBP operation.

NPCIL informed that during test charge, flash over light was observed in GIS and on visual inspection, through inspection window, flashover marks were noticed in ADL15 (230KV KKNPP-S.R.Puduar) Bus-A

Annexure-B


disconnector compartment (which resulted in Bus-A BBP operation at 21:41 hrs).

Later, on 07.12.2021, High voltage tests at 5kV were performed to identify the fault location. Bus-A (ADA), 230kV KKNPP SR Pudur line (ADL15) and bus coupler were isolated for normalization of 230kV GIS.

On 08.12.2021 Bus-B (ADB) charged through 230kV KKNPP- TTPS (ADL31) transmission line. Subsequently ICT-1&2 synchronized in 400kV GIS. CSAT, unit-1&2 RAT were charged.

NPCIL informed that 230kV GIS Bus-A disconnector flashover rectification is highly specialised work and need to be carried out through GIS manufacturer/expert.

SRPC enquired regarding status of the rectification work. NPCIL replied that tendering work was under progress and rectification work is expected to be completed in 3 months’ time.

2.

Tripping of HVDC VSC 320KV-PUGALUR THRISSUR Pole -1

17-Dec-2021 07:46:00 hrs

Pole-1 tripped due to CWC (convertor water cooling) trip. AC supply fault was in UPS which results in both UPS going into battery operation and pump change over didn't take place. Findings and remedial actions taken shall be furnished.

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Tripping of 320kV HVDC VSC Pugalur – Thrissur Pole-1: Pugalur (PGCIL-SR-2) end:

As per FIR/ DR/ EL/ TR HVDC Pole-1 tripped at 07:46:22.898 hrs on converter cooling water fault and sent ESOF signal to Thrissur end.

As per FIR Pugalur HVDC AC supply to water cooling system had a momentary disturbance, which resulted in both UPS to go in battery operation. At the same time Pump 2 which was running had a run-time fault and pump changeover did not happen due to UPS battery operation. As a result, Trip initiated and ESOF signal sent to Trissur end.

Thrissur (PGCIL-SR-1) end:

As per FIR/ DR/ EL/ TR HVDC Pole-1 tripped at 07:46 hrs on receipt of ESOF signal from Pugalur end and went to decoupled mode.

As per PGCIL-SR2 Report dated 11.02.2022: Sequence of Events:

A momentary AC LT supply disturbance occurred in UPS input supply at 07:46:16 which resulted in CWC AC supply fault.

Due to this CWC AC supply fault, both UPS went to battery operation at 07:46:16 and Both UPS went into static bypass operation.

VSC-Pole-1 got tripped on 07:46:22 hrs due to CWC Backup Trip, Link -1 went into standby mode at Pugalur and in decoupled mode at Trichur.

The VSC link -1 normalized at 11:58:36 hrs after completion of the discharge time at both the station end converters.


Annexure-B


Deliberations:

As per tripping files furnished, 320 kV HVDC VSC Pugalur – Thrissur Pole-1 tripped at 07:46:22.898 hrs on converter cooling water fault at Pugalur and ESOF signal was sent to Trissur end.

PGCIL-SR2 informed that HVDC AC supply to water cooling system had a momentary disturbance, which resulted in both UPSs to go in battery operation. At the same time Pump 2 which was running had a runtime fault and pump changeover did not happen to UPS battery operation.

PGCIL-SR2 informed that this occurred as UPS main ON delay time and rectifier soft start time got reset to 0 sec.

Normally Mains ON delay time of 3 seconds for UPS-1 and 5 seconds for UPS-2 are kept to allow the input supply to settle after momentary Supply disturbances/changeovers if any.

Rectifier soft start is set to 110% A for 5 sec for the smoother transfer of load on input supply which avoids sudden load transfer on input power source.

Since these time delays were reset to zero, due to momentary disturbance on AC side, both UPS immediately went to battery mode and supply to pump was interrupted. During momentary disturbance in AC source, due to under voltage in UPS circuit, current in the circuit overshot and UPS block occurred. Hence power supply to pump was interrupted. Since CWC pump supply was interrupted, Trip was initiated and ESOF signal sent to Trissur end.

PGCIL-SR2 informed that after the event all time delays were reset to earlier settings. Hence in the event of any similar incidence UPS would support 110% of overload for 5 sec.

Noting that the reasons for resetting of the stated UPS parameters (time & cause when they got reset) were not clear, SRPC asked PGCIL-SR2 to troubleshoot the reasons for reset of various time delays related to UPS, and to ensure that similar event does not repeat in future.

SRPC also noted that HVDC Pugalur was having two AC sources for LT bus, but at any time only one source is used, and both UPSs are fed from same AC supply. In this regard, PGCIL-SR2 was requested to provide automatic changeover arrangement for LT Sources for more reliability.

In this regard, LT side SLDC as furnished by PGCIL-SR2 vide mail dated 23.02.2022 is reproduced below for kind reference:

Annexure-B


3. Tripping of 400/220kV ICT-1 at RAICHUR TPS

18-Dec-2021 10:16:00 hrs

As per the report submitted, triggering incident was operation of 33KV side ZIGZAG transformer Earth fault relay. Tripping is not in order as the zigzag transformer was not in service. Tripping needs review. Findings and remedial actions taken shall be furnished.

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SLD:


Tripping of 400/220kV ICT-1 at Raichur (KPCL):

As per FIR/ TR, ICT-1 at Raichur tripped at 10:16 hrs on operation of 33KV side ZIGZAG transformer Earth fault relay.

KPCL informed that the ZigZag Transformer was in isolated condition.

DR/ EL not available. Remedial Actions Taken: Isolated the Earth fault relay since the ZigZag Transformer not in service. Charged the ICT after the clearance from LDC @ 10:36hrs Deliberations:

As per tripping files furnished, ICT-1 at Raichur tripped at 10:16 hrs on operation of 33KV side ZIGZAG transformer Earth fault relay. KPCL informed that the zigzag transformer was not in service, but the earth fault relay of the same operated.

SRPC requested KPCL to look into the reason for operation of the earth fault relay. KPCL informed that the earth fault relay had been isolated after the issue.

Annexure-B


4. Tripping of 400kV RAICHUR - BTPS

23-Dec-2021 03:45:00 hrs

As per the report submitted, the triggering incident was RE fault in the line. A/R is in non-auto mode since both the ends are connected to generators. The fault was sensed in Zone-1 at both ends. At Raichur end, line tripped on 3ph Zone-1 distance protection. At BTPS end, as per DR, even after 3 phase trip, after 100ms from the opening of breakers, the fault was observed and the same needs review.

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Connectivity Diagram:

Antecedent Conditions: At RTPS:

At BTPS: One and Half Breaker scheme

Tripping of 400kV Raichur – BTPS line: Raichur (KPCL) end:

As per FIR/ DR/ EL/ TR line tripped on R-E fault at 03:44:45.944 hrs on operation of DPR zone-1. A/R not enabled since line is between two generating stations (Ir-5.2kA; 64.6km).

BTPS (KPCL) end:

As per FIR/ DR/ EL/ TR line tripped on R-E fault at 03:44:20.814 hrs on operation of DPR zone-1. A/R not enabled since line is between two generating stations (Ir-3.58kA; 87.6km).

Annexure-B


EL furnished was insufficient to explain the second fault

In DR, after 3-ph Z1 trip at 03:44:20.814 hrs, the fault currents were observed to have come down to zero. (Whether CB opened or not is known). Then after about 200 msec, another R-E fault occurred, which got cleared by DPR in Zone-1.

Deliberations:

As per tripping files furnished, line tripped in 3-ph on R-E fault on operation of DPR Zone-1 at Raichur end. At BTPS end the line tripped in 3-ph on R-E fault on operation of DPR zone-1 but after 200msec, another R-E fault occurred, which got cleared by DPR in Zone-1.

A/R was disabled in the line since it is between two generating stations. KPCL informed that the reason for tripping could not be determined.

KPCL informed that CB might have reclosed after first fault, since A/R close pulse is detected in DR.

SRPC pointed out that the fault currents were observed to have come down to zero after operation of distance relay on first fault. Since currents were observed after 200 msec, it appears that CB might not have opened properly. But, in such a case, LBB should come into picture. Whether CB tripped properly (in all three phases), and the reasons for detection of another fault after 200 msec needed to be investigated. A/R initiation off and enabling of non-auto mode of A/R shall also be checked in all relays.

KPCL was asked to investigate, check Main-2 relay DR as well, and submit a detailed, report including the remedial measures taken for the tripping in two weeks time.

Recommendations:

KPCL to investigate reason for unexpected behavior of protection relays at BTPS end for the subject line and submit a detailed report including the remedial measures taken in two weeks time.

5. Tripping of 400 kV Pavagada-Tumkur-2

24-Dec-2021 10:41:00 hrs

During antecedent conditions, while test charging, 400kV Pavagada - Tumkur Line-1 was under charged condition at Pavagada end and open at Tumkur end. Triggering incident was, R-N fault in Pavagada - Tumkur line-1. At Pavagada end of 400kV Pavagada - Tumkur Line-1, fault was sensed in Zone-2 and line got tripped with a delay of 480ms. At Tumkur end of 400kV Pavagada - Tumkur Line-2, the same fault was sensed as R-B fault in Zone-2 and line got tripped with a delay of 360ms. Zone-2 clearance time of Tumkur of 400kV Pavagada - Tumkur Line-2 is less than Pavagada end of 400kV Pavagada - Tumkur Line-1 and this led to tripping of 400kV Pavagada - Tumkur Line-2 at Tumkur end. Tripping is not in order and needs review.

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Tripping of 400kV Pavagada – Tumkur line-2 Pavagada(PGCIL-SR2) end:

As per FIR/ TR, line was in service at Pavagada end.

Annexure-B


Tumkur (PGCIL-SR2) end:

As per FIR/ TR, line tripped at 10:41 hrs for R-B fault in 400kV Pavagada – Tumkur line-1 on operation of DPR Zone-2.

As per EL, line tripped at 10:40.16.956 hrs on operation of DPR Zone-2.

Zone-2 pick-up also to be configured in EL to determine Zone-2 operating time.

As per FIR FSC was in service for 400kV Pavagada – Tumkur line-2. As per PGCIL-SR2 Report dated 10.02.2022:

Annexure-B


Annexure-B



PGCIL-SR2 informed the following RM vide email dated 11.02.2022:

Deliberations:

As per the tripping files furnished, in the antecedent condition, 400kV Pavagada-Tumkur line-1 was under outage. Charging attempt was made for the line from Pavagada end, by bypassing the FSC. During the time after 18sec time delay a fault occurred in Z2 from Pavagada end.

The fault was detected in Zone-2 by Tumkur end relay of 400kV Tumkur-Pavagada line-2 and tripped with a delay of 350msec. The time delay of DPR Zone-2 at Pavagada end of 400kV Pavagada-Tumkur line-1 was 500msec, the relay operated after tripping of 400kV Tumkur-Pavagada line-2 from Tumkur end.

PGCIL-SR-2 informed that the issue occurred mainly due to distance relay Zone-2 time coordination issue due to series compensation. Hence, they proposed charging of the series compensated line from Tumkur end followed by synchronisation from Pavagada end. As the Z2 timing at Tumkur end is only 350mSec, always Tumkur end relays can clear the fault in the event of slow developing fault as occurred in case of subject tripping.

In this connection, SRPC pointed out that while the PGCIL-SR2’s proposal of charging series compensated line from Tumkur end followed by synchronisation from Pavagada end is in order, and suitable instructions can be given to station personnel to that effect, it is appropriate to keep Zone-2 timing of Uncompensated end more than that of compensated end. Accordingly, PGCIL-SR2 was requested to take steps to implement the same accordingly.

6.

Tripping of 110kV Bus-1 at 220/ 110 kV Madakathara SS of KSEBL

20-Jan-2022 11:40 hrs

As per the report submitted, all the elements were connected to 110kV Bus-1 at 220kV/110kV Madakathara SS since 110kV Bus-2 was under planned outage. Triggering incident was R phase fault in 110kV Bus-1. Due to non-operation of 110kV Bus-1 BBP, fault was cleared by tripping of transformers and feeders at remote ends. This resulted in 110kV side bus De-Energization of 220kV/110kV Madakathara SS.

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Annexure-B


SLD:


Annexure-B


Station Bus configuration and arrangements at 110kV Bus: Double Bus scheme Bus arrangement:


110kV Bus-2 at Madakathara was under work permit and all elements were connected to 110kV Bus-1. Tripping of 220/ 110kV 200MVA ICT-1 , 2 & 3 at Madakathara (KSEBL):

As per FIR/ TR 220/ 110kV ICT-1, 2 & 3 tripped at 11:58 hrs on operation of LV side Backup earth fault protection.

As per EL of 220/ 110kV ICT-2, it tripped at 11:40:27.684hrs on operation of LV side Overcurrent protection.

LV side OC relay kept non-directional. Operating time of LV side overcurrent operation could not be determined.

Tripping of 220kV Madakathara Elankur line: Madakathara (KSEBL) end:

As per FIR/ TR line did not trip at Madakathara end. Elankur (KSEBL) end:

As per FIR/ EL/ TR line tripped at 11:58 hrs on R-Y-B fault due to operation of overcurrent protection (Td=500msec).

As per KSEBL Report dated 10.02.2022:

Annexure-B


Remedial Measures Taken: KSEBL vide report dated 10.02.2022 informed the following Remedial measures:

Deliberations:

As per tripping files furnished, in the antecedent condition 110kV Bus-2 at Madakathara was under work permit and all elements were connected to 110kV Bus-1.

The triggering incidence for the events was R-Y-E fault on 110kV Bus-2 at Madakathara. BBP did not operate. KSEBL informed that the bus fault was due to wrong operation of bus isolator of 220/110kV, 200MVA transformer-3, due to which R-ph of the isolator came into arcing vicinity of Bus-2 which was live. KSEBL informed that the moving mechanism of isolator had mechanical play/was loose and the same was rectified.

The fault was cleared by tripping of 220/ 110kV transformers on operation of LV side back up protection and tripping of all lines at remote end.

As per tripping file of 220kV Madakathara-Elankur line, it tripped at Elankur end on operation of overcurrent protection. KSEBL informed that during trouble shooting it was found that OCR relay was enabled to trip instead of alarm and the same was rectified.

110/ 11kV transformers tripped on operation of non-directional earth fault protection.

110kV lines 1MDVI1 & 2 tripped at remote end on operation of overcurrent protection and 1MDOL tripped on DPR Zone-2. 110kV MDCE did not trip instead adjacent feeder, from Cherpu to Irinjalakuda tripped at Irinjalakuda SS end.

Distance relay of 110kV MDWD maloperated at Madakathara end and the same was replaced by numerical relay.

KSEBL informed that non-operation of 110kV BBP was due to card failure of BBP relay. They apprised the forum that the faulty card of SBNH 163 and current check relay MCTI had been replaced and BBP was put back into service.

KSEBL informed that since there was no provision for any kind of watchdog in the BBP relay, card failure could not be detected beforehand. The static 110kV BBP was proposed to be replaced by numeric BBP and work was under progress. Timeline for completion of work was stated to be 4 months.

Annexure-B


7.

Tripping of 220 kV ASUPAKA - LOWER_SILERU-1

20-Jan-2022

22:48:00 hrs

As per the report submitted, triggering incident was Y-N fault in the line at a distance of 21KM from Asupaka end. At both the ends, fault was sensed in zone-1. At Asupaka end, A/R operated line tripped on persistent fault in Zone-1. At Lower Sileru end, A/R operated and line tripped on operation of zone-1 with a delay of 400ms after reclose. Delayed fault clearance at Lower Sileru end needs review.

0 0

GI-1

21-Jan-2022

01:22:00 hrs

0 0

21-Jan-2022

10:40:00 hrs

0 0


Tripping on 20-Jan-2022 22:48:00 hrs Asupaka (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph at 22:48:04.899 hrs on Y-E fault due to operation of distance protection zone-1 and A/R attempted to reclose but tripped in 3-ph on operation of SOTF/ TOR due to persisting fault (21.4km).

Lower Sileru (APGENCO) end:

As per FIR/ DR/ EL/ TR line tripped in Y-ph at 22:48:04.929 hrs on Y-E fault due to operation of distance protection zone-1 and auto-reclosed successfully but tripped in 3-ph on Y-E fault due to DPR, Z1 operation but with a delay of 400msec (75.18km).




As per FIR/ DR/ EL/ TR line tripped in Y-ph at 01:22:42.268 hrs on Y-E fault due to operation of distance protection zone-1 and auto-reclosed successfully but tripped in 3-ph on Y-E fault due to DPR, Z1 operation but with a delay of 400msec (74.84km).



Annexure-B



As per FIR/ DR/ EL/ TR line tripped in Y-ph at 10:40:31.152 hrs on Y-E fault due to operation of distance protection zone-1 and auto-reclosed successfully but tripped in 3-ph on Y-E fault due to DPR, Z1 operation but with a delay of 400msec (75km).

Deliberations:

As per tripping files furnished, on all the instances, line tripped at Asuapaka end in Y-ph on Y-E fault due to operation of distance protection Zone-1 and A/R attempted to reclose but tripped in 3-ph on operation of TOR due to persisting fault.

At Lower Sileru end, line tripped in Y-ph on Y-E fault due to operation of distance protection zone-1 and auto-reclosed successfully but tripped in 3-ph after 400msec. APGENCO informed that trouble shooting was under progress, relays were tested and report regarding the measures taken would be furnished.

SRPC expressed concern regarding the delay in troubleshooting in respect of improper tripping and requested APGENCO to promptly take requisite action in such cases in future. Concern was also raised regarding charging of line without proper line inspection and requested utilities to follow standard operating practices while charging of a line after the line trips on (permanent) fault.

Recommendations: APGENCO to troubleshoot to identify the reason for improper tripping of the line during the incidence,

and to follow standard operating practices while charging of a line after the line trips on fault.

8. Tripping of 400 kV KAIGA - GUTTUR line-1

22-Jan-2022 11:03:00 hrs

As per the report submitted, line tripped at Kaiga end on operation of OV St-2 protection instantaneously.

0 0 GI-2

Installed Capacity: 4x220 MW SLD:

Annexure-B



Tripping of 400kV Kaiga – Guttur line -1: Guttur (KPTCL) end:

As per FIR / TR, line did not trip at Guttur end. Kaiga (NPCIL) end:

As per FIR/ DR/ EL/ TR, line tripped at 11:03:48.363 hrs.

As per TR, NPCIL informed that Kaiga-Guttur Line-1 tripped on Y-Phase Instantaneous Over voltage protection on 22/01/2022 at 11:03 hrs. Over voltage recorded in the disturbance recorder is 359.933KV i.e., 1.56 times of rated Phase voltage.

DR furnished was not okay (no analog & digital signals found; all waveforms were found overlapped).

EL furnished also did not record the type of protection operated. Deliberations:

As per tripping files furnished, 400 Kaiga – Guttur line-1 tripped only at Kaiga end on Y-Phase Instantaneous Over voltage protection. NPCIL informed that overvoltage recorded in the DR was 1.56 times of rated Phase voltage.

SRPC pointed out that the overvoltage was momentary and a delay of 100msec has to be incorporated during operation of OVR stage-II protection in order to avoid spurious trippings. It was also informed that OVR operation shall be configured to send DT to remote end.

NPCIL-Kaiga informed that OVR stage-II was set to 120% overvoltage. SRPC informed that the same shall be revised to 140% in line with the standard settings adopted uniformly by all utilities in India.

Recommendations: NPCIL-Kaiga to implement the following at their Kaiga GS:

(i) OVR Stage-II protection settings shall be revised to 140% with a delay of 100msec (ii) OVR protection shall be configured to send DT to remote end upon its operation

Annexure-B


9.

Tripping of 400 kV URAVAKONDA – VELTOOR Line-1

25-Jan-2022 09:12:00 hrs

As per the information received, line tripped at Uravakonda end due to suspected mal-operation of OV St-1 protection and DT was received at Veltoor end. Findings and remedial actions taken shall be furnished.

0 0 GI-2


Tripping of 400kV Uravakonda – Veltoor line-1: Veltoor (TSTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 09:12:44.316 hrs on receipt of DT from remote end. Uravakonda (APTRANSCO) end:

As per FIR/ DR/ EL/ TR line tripped at 09.12.44.388 hrs on operation of OVR stage-1 and DT was sent to Veltoor end.

OVR grading as per SRPC OVR-2021: (D; 110% 8 sec)

Voltage Value and Time delay could not be verified from DR/ EL.

DR/ EL to be configured to capture OVR start as well. Deliberations:

As per OVR-2021:

As per tripping files furnished, 400kV Uravakonda – Veltoor line-1 tripped at Uravakonda end on

operation of OVR stage-1 protection and at Veltoor end on receipt of DT.

APTRANSCO was asked to capture both OVR-Start and OVR-Trip events in in EL to enable verification of OVR grading and intimate voltage values in tripping reports. They were also requested to check drop off to pick up ratio of OVR relays at Uravakonda end, and ensure that it is more than 0.98.

Annexure-B


10.

Tripping of 400/ 220 kV RAYADURG ICT 1 and 2

29-Jan-2022 17:05:00 hrs

ICTs tripped due to DC supply failure. Details are awaited.

0 0 -

Tripping of 400kV/220kV RAYADURG ICT 1 and 2:

No Tripping files furnished in SRLDC portal. As per TSTRANSCO Report dated 11.02.2022:

The pre-commissioning activities of 220kV, 132kV feeders & PTRs are under progress in Raidurg Substation Complex.

Due to DC earth leakage there was spurious tripping of ICTs.

Suspecting problem with wiring after PSD devices in the Main & Tie Circuit breakers of ICTs. Requested the OEM for site visit for rectification of the same.

Deliberations:

TSTRANSCO informed that the SS was commissioned recently and 400/ 220 kV RAYADURG ICT 1 and 2 tripped on DC supply failure due to DC earth leakage in the station.

They informed that problem was suspected with wiring after PSD devices in the Main & Tie Circuit breakers of ICTs. They have requested the OEM for site visit for rectification of the same.

III. Tripping Events due to Failure or Non-operation of Auto-reclosure:

Sl. No

Element Date & Time

Reason

1

400kV SALEM - NNTPP-1

01-Dec-2021 05:51:00 hrs

As per the report submitted, triggering incident was Y-N fault in the line at a distance of 23 km from NNTPP end. At Salem end, fault was sensed in zone-1. A/R operated and line was holding. At NNTPP end, zone-1 protection operated and line got tripped. A/R did not operate at NNTPP end and the same needs review.

Salem (PGCIL-SR2) end:

As per tripping files line successfully auto-reclosed on Y-E fault at Salem end. NNTPP end:

As per tripping files line tripped in 3-ph on Y-E fault and did not auto reclose.

NNTPP informed that auto reclose issue in Main 1 relay is being sorted out and is informed to the OEM.

Deliberations:

As per tripping files furnished, 400kV Salem – NNTPP line-1 tripped in Y-ph on Y-E fault at Salem end and auto reclosed successfully. At NNTPP end line did not initiate A/R and tripped in 3-ph.

NNTPP informed that there was logic problem in P543 relay and the same was rectified. The logic was tested in spare relay. The updated logic would be implemented in relay in next opportunity shutdown.

Remedial Measures Taken: NNTPP informed that there was logic problem in P543 relay and the same was rectified. The logic

was tested in spare relay. The updated logic would be implemented in relay in next opportunity shutdown.

Annexure-B


2 220kV SABARGIRI - THENI

02-Dec-2021 12:26:00 hrs

As per the report submitted, triggering incident was B-N fault in the line at a distance of 31 KM from Theni end. As per the FIR, at Sabarigiri end, fault was sensed in zone-1. A/R operated and line was holding. However, operation of A/R is not seen in the DR. At Theni end, fault was sensed in Zone-1. A/R initiated and line got tripped on pole discrepancy after A/R dead time. A/R did not operate at Theni end and the same needs review.

11-Jan-2022 14:19:00 hrs

As per the report submitted, triggering incident was R-N fault in the line. At SABARIGIRI end fault was sensed in Zone-1 with a fault current of 1kA and at a distance of 40km and A/R did not get operated 3ph trip. At THENI end fault was sensed in DEF with a fault current of 0.7kA. Non operation of AR at Sabargiri needs review.

Tripping on 02-Dec-2021 12:26:00 hrs- Sabarigiri (KSEBL) end:

A/R operated successfully, and the line was holding. Theni (TANTRANSCO) end:

Line tripped in B-ph on B-E fault on operation of DPR Zone-1, but did not attempt A/R after it’s A/R dead-time; ultimately tripped at around 1.7 sec due to PDR operation.

TANTRANSCO informed the following vide email dated 10.02.2022: On 03.12.2021, while checking Reclosure circuit, it was observed that reclose command lead

(copper Leg crimping point conductor) cut at relay panel terminal block .The same was set right by providing new leg. After this, the Auto reclosure was found successful during single phase to ground transient fault on 09.12.2021 at 11:57 hrs & 04.01.2022 at 13:26hrs.

Tripping on 11-Jan-2022 14:19:00 hrs Sabarigiri (KSEBL) end:

As per EL, line tripped in R-ph on R-E fault due to operation of DPR Z1 protection, and attempted A/R after it’s A/R dead-time, but not successful; hence tripped in 3-ph.

Theni (TANTRANSCO) end:

Line tripped on R-E fault due to operation of DEF protection. And tripped the line after a time delay of ~ 1.5 sec.

DEF protection signal to be clearly configured in legends. Deliberations:

As per tripping files furnished, in first event line successfully autoreclosed at Sabarigiri end for B-E fault. At Theni end, line initiated A/R but did not reclose and line tripped on PD operation.

TANTRANSCO informed that reclose command lead (copper Leg crimping point conductor) cut at relay panel terminal block was detected and the same was rectified and A/R was put back into service.

During second incidence, line tripped in R-ph on R-E fault and attempted A/R but tripped in 3-ph on persisting fault. Theni end detected it as high resistance fault and hence did not initiate A/R.

Remedial measures Taken: TANTRANSCO informed that while checking Reclosure circuit, it was observed that reclose command

lead (copper Leg crimping point conductor) cut at relay panel terminal block. The same was set right by providing new leg. After this, the Auto reclosure was found successful during single phase to ground transient fault on 09.12.2021 at 11:57 hrs & 04.01.2022 at 13:26hrs.

Annexure-B


3 400kV KAIGA - GUTTUR 2

03-Dec-2021 20:44:00 hrs

As per the report submitted, triggering incident was Y-N fault in the line at a distance of 159KM from Kaiga end. At Kaiga end, the fault was sensed in Zone-1, A/R initiated and the other two poles got opened after A/R dead time. At Guttur end, zone-1 protection operated and line got tripped. A/R did not operate at Guttur due to the I>3 A/r lockout (If-13kA) end. Non-operation of A/r at Kaiga end needs review.

10-Jan-2022 14:00:00 hrs

As per the report submitted, triggering incident was R-N fault in the line. At KAIGA APS end fault was sensed in Zone-1 with a fault current of 2kA A/R did not operate, and issued 3-ph trip instantaneously. At GUTTUR end fault was sensed in Zone-1 with a fault current of 6.5kA A/R start, 1ph trip, during closing AR lock trip resulting 3ph trip. Non operation of AR at both ends needs review.

Tripping on 03 Dec 2021, 20:44hrs Kaiga (NPCIL) end:

Line tripped in 1-ph on Y-E fault. A/R locked out immediately after distance trip, and line did not attempt for A/R; ultimately, the CB tripped on PDR operation.

Guttur (KPTCL) end:

Line tripped in 3-ph on Y-E fault and did not initiate A/R. As per KPTCL Report dated 16.02.2022: Nature of fault: Pilot Insulator flashover at location No.9 Reason for AR block at Guttur end: The fault was close to Guttur station and fault current fed from Guttur was more than 15KA during the incident. There is an additional logic to block AR for faults with very high current. Current limit setting adopted for AR block is 60% of the Guttur 400kV fault level 12 kA). Since the fault current sensed is more than the Current limit set, I>3 logic operated and AR was blocked resulting in 3 phase trip for Zone-1 YN fault. Tripping at Guttur end is in order. Remedial action taken: After replacing insulator the line taken in to service on 06.12.2021 Hrs at 13:28 Hrs. Tripping on 10 Jan 2022, 14:00hrs Kaiga (NPCIL) end:

Line tripped in 3-ph on R-E fault due to DPR Z-1 protection and did not initiate A/R. Guttur (KPTCL) end:

Line tripped on R-E fault on DPR Z-1 protection and attempted A/R but tripped in 3-ph even though there is no persistent fault.

As per KPTCL Report dated 16.02.2022: At Kaiga: M-I,M-II,Zone-1,RN fault, 1.97kA, 136.6km, 3 Phase trip; At Guttur: M-I,M-II,Zone-1,RN Fault, 7.2kA,66.95km; AR operated but due to persistent fault three phase trip occurred. Details From the DR : 14.00.32.198: Zone-1 trip, R phase trip; 14.00.33.381: R phase reclosed 14.00.33.374: AR block Nature of fault: Tree branches coming in arching zone at location 80 and 81. Tripping at Guttur end is in order. Remedial action taken: Tree trimming done and line restored on 11.01.2021 at 14:43 Hrs.

Annexure-B


Deliberations:

As per tripping files furnished, in first incidence the line tripped in Y-ph on Y-E fault at Kaiga end and initiated A/R but tripped in 3-ph and later CB tripped on PD operation. At Guttur end the fault current was more than 15 kA hence A/R was blocked as per logic implemented at Guttur.

During second incidence, the line attempted A/R at Guttur end but tripped due to persisting fault. But Kaiga end line initiated A/R but it was blocked and line tripped on PD operation.

NPCIL-Kaiga was asked to check the reason for failure of A/R at their end for the subject line.

4 220 kV IDUKKI - UDUMALPET

03-Dec-2021 17:49:00 hrs

As per the report submitted, triggering incident was Y-N fault in the line at a distance of 12.58KM from Idukki end. At Idukki end, Zone-1 protection operated and line got tripped. At Udumalpet end, carrier aided zone-2 protection operated and line got tripped. A/R did not operate at both the ends and the same needs review.

22-Jan-2022 08:55:00 hrs

As per the report submitted, triggering incident was R-N fault in the line at a distance of 108KM from Idukki end. At Idukki end, Zone-2 protection operated and line got tripped with a delay of 600ms. At Udumalpet end, fault was sensed in Zone-1. A/R operated and line tripped on persistent fault. Points for review: 1. Non operation of carrier aided zone-2 protection at Idukki end.

Tripping on 03-Dec-2021 at 17:49:00 hrs Fault is multi-phase – Y-B fault. Correct operation. TANTRANSCO informed the following vide email dated 10.02.2022: During the incident, the relay at Udumalpet senses as Line to Line fault, as per DR the fault current is Iy. 2.585 kA & Ib 2.159 KA . Hence Lockout trip.

Tripping on 22-Jan-2022 08:55:00 hrs Idukki (KSEBL) end:

Line tripped in 3-ph on R-E fault due to operation of DPR Zone-2 after delay of 0.5 sec. Udumalpet (TANTRANSCO) end:

Line tripped in R-ph on R-E fault due to operation of DPR Zone-1 and attempted A/R but tripped in 3-ph due to persisting fault.

Deliberations:

As per tripping files furnished, the first incidence was multi-phase fault hence A/R was not attempted at both ends.

During second incidence A/R was attempted at Udumalpet end but line tripped on persisting fault. At Idukki end since carrier was not received A/R was not initiated.

TANTRANSCO and KSEBL was requested to perform end-to-end testing of carrier and DT for the subject line and ensure healthiness of PLCC communication.

Annexure-B


5 220kV KANIAMPET - KADAKOLA

11-Dec-2021 17:38:00 hrs

As per the report submitted, triggering incident was R-N fault in the line at a distance of 51.5KM from Kadakola end at Tower no 159 due to conductor de-capping. At both the ends, fault was sensed in Zone-1 and A/R initiated. At Kaniyampet end, after A/R dead time line got tripped due to pole discrepancy. At Kadakola end, A/R operated and line tripped on persistent fault. Non operation of A/R at Kaniyampet end needs review.

14-Dec-2021 00:56:00 hrs

As per the report submitted, triggering incident was B-N fault in the line at a distance of 66KM from Kaniyampet end at tower no 79 due to conductor decapping. At both the ends, fault was sensed in Zone-1 and A/R initiated. At Kaniyampet end, after A/R dead time line got tripped due to pole discrepancy. At Kadakola end, A/R operated and line tripped on persistent fault. Non operation of A/R at Kaniyampet end needs review.

21-Dec-2021 18:10:00 hrs

As per the report submitted, triggering incident was R-N fault in the line at a distance of 19.5KM from Kadakola end at tower no 70 due to conductor decapping. At both the ends, fault was sensed in Zone-1 and A/R initiated. At Kaniyampet end, after A/R dead time line got tripped due to pole discrepancy. At Kadakola end, A/R operated and line tripped on persistent fault. Non operation of A/R at Kaniyampet end needs review.

Tripping on 11-Dec-2021 17:38:00 hrs Kaniampeta (KSEBL) end:

Line tripped in Y-ph on Y-E fault on operation of DPR Zone-1 and initiated A/R but did not attempt A/R; hence ultimately tripped in 3-ph due to PDR operation.

Kadakola (KPTCL) end:

Line tripped in Y-ph on Y-E fault on operation of DPR Zone-1 and attempted A/R but tripped in 3-ph due to persisting fault.

Tripping on 14-Dec-2021 at 00:56:00 hrs Kaniampeta (KSEBL) end:

Line tripped in B-ph on B-E fault on operation of DPR Zone-1 and initiated A/R. Kadakola (KPTCL) end:

Line tripped in B-ph on B-E fault on operation of DPR Zone-1 and attempted A/R but tripped in 3-ph due to persisting fault.

Tripping on 21-Dec-2021 at 18:10:00 hrs Kaniampeta (KSEBL) end:

Line tripped in R-ph on R-E fault on operation of DPR Zone-1 and initiated A/R. Kadakola (KPTCL) end:

Line tripped in R-ph on R-E fault on operation of DPR Zone-1 and attempted A/R but tripped in 3-ph due to persisting fault.

Annexure-B


KPTCL vide Report dated 16.02.2022 furnished the following: First Event: Nature of Fault: Insulator de-capped at tower location 159. Remedial Action Taken: After attending the fault, the line was test charged on 12.12.2021 at 15:52 Hrs. The line tripped again at 15:56 Hrs due to insulator decap at tower No.249. After attending the fault, the line taken in to service on 13.12.2021 at 17:49 Hrs. Second Event: Nature of fault: Insulator decapped at tower No. 79. Remedial Action taken : After attending the fault, the line taken in to service on 15.12.2021 at 11:12 Hrs. Third Event: Reason For Tripping: Insulator decapped at tower No.70. Remedial Action Taken Details: Line restored on 22.12.2021 at 13:05 Hrs after attending the line fault. Regarding frequent failure of insulators, hotline inspection was carried out. It is suspected that old

and deteriorated insulators in the line section passing through dense forest area have failed. Action is being taken by CEE, TZ, Mysore regarding assessment of healthiness of insulators in this line.

Deliberations:

As per the tripping files furnished, all the 3 incidences were due to insulator decapping. Kadakola end attempted A/R but tripped due to persisting fault. Kaniampeta end initiated A/R in all the events but tripped in 3-ph subsequently without attempting reclosure.

KSEBL informed that on 11.12.2022 CB of the line was replaced at Kaniampeta end and the trippings occurred subsequent to the replacement. On troubleshooting an error in wiring circuit was detected. The same was rectified. The line was kept under observation and detailed testing would be carried out on availability of shutdown.

6 220 kV CHILLAKALLU - PULICHINTALA

20-Dec-2021 10:31:00 hrs

As per the report submitted, triggering incident was R-E fault in the line at a distance of 63.14KM from Chillakallu end. At both ends, fault was sensed in zone-1. At Chillakallu end, A/R operated and line was holding. At Pulichinthala end, A/R did not operate and line got tripped. Non operation of A/R at Pulichinthala end needs review. DR time sync issue at Chillkallu end needs review.

Chillakallu (APTRANSCO) end:

A/R operated and line was holding. Pulichinthala (TSGENCO) end:

Line tripped in 3-ph on R-E fault and did not initiate A/R. TSGENCO informed the following vide email dated 11.02.2022:

At Pulichintala HES A/R function was tested and commissioned in 7SA522 relays (Main-2) for both feeders.

For Main-1, MICOM P442 relays will be replaced with ABB REL 670 relays.

ABB would depute the service engineer in the last week of February’22, for retrofitting, testing and commissioning of REL 670 relays.

A/R function will be implemented by the end of February’2022.

Annexure-B


7 400kV MANALI ALAMATY

24-Dec-2021 12:34:00 hrs

As per the report submitted, triggering incident was Y-N fault in the line. At MANALI end fault was sensed in Zone-1 with a fault current of 4.9kA and A/R got operated and was successful. At ALAMATTY end fault was sensed in Zone-1 with a fault current of 7.7kA and at a distance of 40km and A/R did not get operated and 3 ph tripped. Line tripped only at ALAMATTY. Non operation of AR at Alamatty needs review

Manali (TANTRANSCO) end:

Line successfully auto-reclosed on B-E fault. Almathy (TANTRANSCO) end:

Line tripped in Y-ph on Y-E fault, attempted A/R and tripped in 3-ph after A/R deadtime. TANTRANSCO informed the following vide email dated 10.02.2022:

During the incident, the relay issued the reclosure command after the dead time of 1000msec. but the breaker fails to reclose. Hence lockout trip initiated. The healthiness of breaker including closing / Trip operation were checked & found OK.

A/R found successful during transient fault on 27.01.2022 at 12:00 hrs

Annexure-B


8 400 kV VTPS-SURYAPET Line-2

30-Dec-2021 10:39:00 hrs

As per the report submitted, triggering incident was R-E fault in the line at a distance of 122KM from Suryapet end. At VTPS end, Zone-1 protection operated and line got tripped. It was mentioned that, 400kV Bus-2 was under LC and Main CB was out of service which resulted in non-operation of A/R. At Suryapet end, fault was sensed in Zone-1. A/R operated and line was holding. Tripping is not in order due to non-operation of A/R at VTPS end.

VTPS (APGENCO) end:

Line tripped in 3-ph on R-E fault. APGENCO informed that A/R not attempted since the line was charged only through Tie-CB.

Suryapet (TSTRANSCO) end:

Line successfully auto-reclosed. Deliberations:

As per tripping files furnished, APGENCO informed that A/R was not enabled in the line during the time of the incidence at VTPS end, since it was charged only through Tie CB.

SRPC pointed out that A/R shall be enabled even when line charged only through Tie CB. When both Main and Tie CB are available, priority shall be given to Main CB compared to Tie-CB.

Accordingly, APGENCO was asked to take steps to enable A/R when the line is charged only through Tie-CB.

9 220kV UPPER JURALA-RAICHUR KA-1

09-Jan-2022 00:53:00 hrs

As per the report submitted, triggering incident was R-N fault in the line at a distance of 13Km from Jurala end. At both the ends, Zone-1 protection operated and line got tripped. Non-operation of A/R at both ends need review.

23-Jan-2022 00:38:00 hrs

As per the report submitted, triggering incident was R-N fault in the line. Non-operation of A/R at both ends need review.

Tripping on 09-Jan-2022 00:53:00 hrs and 23-Jan-2022 00:38:00 hrs Upper Jurala (TSGENCO) end:

Line tripped in 3-ph on R-E fault and did not initiate A/R. Raichur_KA (KPTCL) end:

Line tripped in 3-ph.

No legends in DR.

No Proper EL submitted. TSGENCO informed the following vide email dated 11.02.20222:

At Upper Jurala HEP A/R function was tested and commissioned in ABB REL670 (Main-1) relays for both Raichur – 1 & 2 feeders.

A/R function was not available for MICOM P437 (Main-2) relays. MICOM P437 relays will be going to replace with MICOM P442 relays.

Order was placed for retrofitting, testing & commissioning of MICOM P442 relays for Raichur-1 & 2 feeders. A/R function will be implemented by the end of March’2022.

As per KTPCL Report dated 16.02.2022: At Raichur: M-I: Zone-1, RN fault, Distance:13.7 kms, If:3.57 kA; At Jurala: M-I,M-II,Zone-1, RN fault, Reason: Transient Fault, Line stood Ok after test charging.

Annexure-B


Remedial Measures details: Auto reclosure was not in service for 220 kV Raichur - Jurala lines. At Raichur, it was ready for

enabling Auto reclosure for Jurala lines. Readiness at Jurala end to be confirmed by TSGENCO. The Raichur end DRs were not time synchronized due to problem with GPS time synchronization

unit, action was being taken to rectify the problem. Compliance report would be submitted SRPC/SRLDC in this regard.

Deliberations:

As per tripping files furnished, A/R was not enabled for the line and hence line did not initiate A/R. KPTCL informed that A/R had been enabled at Raichur end.

TSGENCO informed that as A/R function was not available for MICOM P437 (Main-2) relays it was not enabled. MICOM P437 relays would be replaced with MICOM P442 relays and A/R would be enabled.

10 220kV ASUPAKA - LOWER_SILERU-1

15-Jan-2022 13:12:00 hrs

As per the report submitted, triggering incident was R-N fault in the line at a distance of 37KM from Asupaka end. At Asupaka end, fault was sensed in zone-1. A/R operated and line was holding. At Lower Sileru end, zone-2 protection operated and line tripped with a delay of 300ms. Points for review: 1. Non operation of carrier aided zone-2 protection at Lower Sileru end

Asupaka (TSTRANSCO) end:

Line successfully reclosed on R-E fault. Lower Sileru (APGENCO) end:

Line tripped in 3-ph on R-E fault on operation of DPR Zone-2. Deliberations:

As per tripping files furnished line did not initiate A/R at Lower Sileru end due to non-receipt of carrier. TSTRANSCO informed that carrier was send during the incidence. APGENCO informed that for the line carrier signal is unreliable; signals were being received at random instances.

APGENCO and TSTRANSCO were asked to carry out end-to-end testing for carrier and DT signal and ensure healthiness of PLCC equipment.

11 400 kV SALEM - UDUMALPET 2

19-Jan-2022 19:38:00 hrs

As per the report submitted, triggering incident was Y-E fault in the line due to R-phase LA failure at Salem end. At Salem end, fault was sensed in Zone-1. A/r operated and line tripped on persistent fault. At Udumalpet end, Zone-2 protection operated and line tripped with a delay of 400ms. Points for review: 1. Non operation of carrier aided zone-2 protection oat Udumalpet end.

Salem (PGCIL-SR2) end:

Line tripped in Y-ph auto-reclosed successfully but tripped later due to persisting fault. Udumalpet (PGCIL-SR2) end:

Line tripped in 3-ph on Y-E fault due to operation of DPR Zone-2. Deliberations:

PGCIL-SR-2 informed that line did not initiate A/R at Udumalpet end due to non-receipt of carrier even though it was sent from Salem end. Due to non-reliability of PLCC one channel was replaced with DTPC. Second channel of PLCC would also be replaced by February, 2022 end.

Annexure-B


IV. Tripping Events due to PLCC mal-operation:

Sl. No

Element Date & Time

Reason

1

Tripping of 400kV Maradam-Kalpakka-1 and 2

08-Dec-2021 13:05:00

As per the report submitted, triggering incident was receiving DT at Kalpakka end from Maradam end for both 400kV Maradam Kalpakka line-1&2. Both the lines tripped only at Kalpakka end. Tripping is not in order and needs review.

14-Dec-2021 16:00:00

Tripping on 08-Dec-2021 13:05:00 Maradam (APTRANSCO) end:

As per FIR, Line did not trip at this end. Spurious DT was sent from Maradam. Kalpaka (APTRANSCO) end:

Line tripped on receipt of DT. Deliberations:

As per tripping files furnished, line tripped at Kalpaka end due to spurious DT sent from Maradam end. APTRANSCO informed that the input voltage for DT signal was 80V. Hence whenever fault was occurring around Maradam DT was being sent to Kalpaka.

The input voltage was increased to 150-160V in order to avoid such spurious tripping. Remedial Measures Taken: The input voltage of DT signal was increased to 150-160V in order to avoid such spurious tripping

2 Tripping of 400kV GHANI - NARNOOR 2

14-Dec-2021 20:05:00

As per the report submitted, triggering incident was receiving DT at Ghani end and line got tripped only at this end. Suspected PLCC maloperation. Tripping is not in order and needs review.

Ghani (APTRANSCO) end:

Line tripped on receipt of DT. Narnoor (APTRANSCO) end:

Line did not trip at this end. Deliberations:

Line tripped at Ghani end on receipt of DT. APTRANSCO informed that DTPCs are available at these stations. End-to-end testing was carried out by APTRANSCO but nothing could be concluded.

SRPC suggested to check to confirm that there is no DC earth leakages in SS.

3 Tripping of 400kV SIMHADRI- KALPAKKA 2

18-Dec-2021 20:47:00

As per the report submitted, line tripped at both the ends on DT receive. Suspected PLCC maloperation. Findings and remedial actions taken shall be furnished.

Simhadri (NTPC) end:

As per TR line tripped on DT receipt.

But no DT signal in DR/ EL. Kalpaka (APTRANSCO) end:

Line tripped on DT receipt.

Annexure-B


Deliberations:

As per tripping files furnished, line tripped at Kalpaka end due to spurious DT. APTRANSCO informed that the input voltage for DT signal was 70V. Hence whenever fault was occurring in nearby locations DT was being sent to Kalpaka.

The input voltage was increased to 145V in order to avoid such spurious tripping. Remedial Measures Taken:

The input voltage of DT signal was increased to 145 V in order to avoid such spurious tripping

4 400kV KAYATHAR - KARAIKUDI 1

28-Dec-2021 15:53:00

As per the report submitted, triggering incident was receiving DT at Karaikudi end and line got tripped only at this end. Tripping is not in order and the same needs review.

Kayathar (TANTRANSCO) end:

Line did not trip. DT sent due to DC leakage. Karaikudi (PGCIL-SR-2) end:

Line tripped on receipt of DT. Deliberations:

As per tripping files furnished line tripped on receipt of DT at Karaikudi end. TANTRANSCO informed that DT was from Kayathar end due to DC leakage. DC earth leakage was due to dilapidated cables and the same were replaced.

Remedial Measures Taken: TANTRANSCO informed that DT was from Kayathar end due to DC leakage. DC earth leakage was due

to dilapidated cables and the same were replaced.

*****

Annexure-B

Meeting

No /

Index

Details of Event Date & Time Reason PCSC RecommendationsUtility responsible for

ImplementationStatus of Implementation of PCSC Recommendations Remarks

Latest Status

(To be filled up by the Constituent)

Status of Pending Implementation of PCSC Recommendations as on 26 February , 2022 (Updated up to 100th Meeting)

KPTCL Mail dated 27-05-2015:

1. KPTCL has taken action to provide bus bar protection to 220kV buses. --- Pending

2. Over current relay Settings of ICTs to be reviewed by PGCIL.

--- Pending

3. --- Pending

KPTCL Mail dated 29-07-2015:

1. Initial Tendering stage. --- Pending

2. --- Pending

3. --- Pending

KPTCL Mail dated on 23-01-2016:

1. Detailed estimate prepared for taking up the work. CEE, Transmission Zone, Gulbarga will take up necessary procurement and

further execution. --- Pending

2. --- Pending with PGCIL (SR-I).

3. --- Pending

PGCIL (SR-I) Mail dated 14.07.2016:

2. Relay settings of all the stations in SRTS-1 were derived as per Ramakrishna Commettee recomendations and implemented" ---

Completed.

KPTCL Mail dated 16.12.2017:

1) & 3). DPR is approved. Tender is to be called by CEE,TZ Kalaburgi --- Pending

Review Meeting dated 19.12.2017:

1. KPTCL informed that Tenders for providing BBP would be called in Jan-Feb, 2018; Supply of the same is targeted by September,

2018; Erection & Commissioning is targeted by January, 2019

--- Pending

3. PGCIL (SR-I) informed that time-synchronization of 220 kV side is in place. --- Completed.

KPTCL mail dated 19.12.2018:

1. DPR preapared for the work of providing Bus Bar Protection to 220kV buses at Guddadahally is approved. Tender is to be

invited by CEE,TZ .


1. Tender would be floated in January 2019. Works would be completed in 6 months after awarding PO.


1. KPTCL informed that the work is expected to be completed by December 2019.

KPTCL mail dated 12-10-2021

Tender for the subject work was called by the SEE,W&M Circle Munirabad . Presently the work has been awarded. Supply of

required materials awaited during October 2021.

16-07-201434/I/6400/220 kV ICT-1 & 2 at

Munirabad

As reported directional over current relay of ICT’s operated

due to snapping of line jumper in 220kV Lingapur line.

1. Bus bar protection shall be provided by asset owner ( i.e KPTCL).

2. Settings for main distance protection & Overcurrent protection shall be examined and

reviewed.

3. Time synchronization of the Substation shall be ensured.

KPTCL/

PGCIL (SR-I)

Pending

(with KPTC,KSEBLL)

Multi-Utilities

Annexure-C

Page 1 of 52

NTPC mail dated 07.12.2017:

1. High set DEFR on 220 KV lines is disabled ----Completed

2. ---- Pending


TSTRANSCO informed that the works are under progress, and are targeted to be completed in 3 months time.

TSTRANSCO MAIL DATED 20.01.2018:

Line Differential Protection will be provided within 3 months i.e., by end of March, 2018.


Line Differential Protection relays are under procurement and will be provided by end of May, 2018.


Line Differential relays will be supplied to site by manufacturer by end of May, 2018 and erection will be completed by end of June,

2018.


Inspection of the relays is completed and the relays are received at stores. Relays are to be drawn and commissioned. Work is

expected to be completed by end of December 2018.


Relays will be commissioned by end of February, 2019.

TSTRANSCO mail dated 22.06.2019:

2. Relay erection work is under progress and will be completed by end of July, 2019.


LDP relays are available but commissioned was not done bue to non availability of carrier communication cable and will be done in 2

months i.e., by December, 2019.


LDP relays are available at site. carrier communication cable laying between the LDPs is procured and laying work is under progress

and will be completed by end of January,2020.

Commissioning of LDPs will be done by 2nd week of February, 2020.


2. Still the telecom communication cable laying is under progress and will be completed by December 2020. After completion of

cable laying, commissioning of LDPs will be done. --- Pending

TSTRANSCO MAIL DATED 04-10-2021:

TSTRANSCO:

LDPs are implemented for all the ICTs at TSTRANSCO end on 25-02-2021.

For 315MVA ICT-5, LDP was not implemented at NTPC end.

APTRANSCO maild ated 30.01.2018:

1. Pending...

2.A/R scheme on 400kV Kurnool (PGCIL) feeder-2 will be checked after getting LC.

APTRANSCO maild ated 24.04.2018 & 24.05.2018 & 26.06.2018:

1. Pending...

2. B Ph auxilary trip relay is found defective. The same is to be replaced by M/S PGCIL. Ii) PD relay event is configured in the EL as

per the recommendation.

02-10-2017 at 02:03

hrs

Tripping of 400 kV

Kurnool(PG) – Kurnool(AP)

line-2

69/III/3APTRANSCO/

PGCIL (SR-I)

1) PGCIL (SR-I) and APTRANSCO to provide for Line Differential Protection as both the

Main protections on 400 kV Kurnool (AP) – Kurnool (PG) lines 1 & 2 lines.

2) APTRANSCO to furnish an action taken report w.r.t. resolving A/R non-operation at

Kurnool-AP end for the subject trippings and configure EL for capturing PDR operation at

their 400 kV Kurnool-AP SS.

Line tripped on B-ph to ground fault. A/R was unsuccessful at

both Kurnool (AP) and Kurnool (PG) ends.

66/ II/ 10Tripping of 400/ 220 kV ICT’s

– 3 & 4 at Ramagundam STPS

NTPC-Ramagundam/

TSTRANSCONTPC Pending

Triggering incident was failure of 220 kV

B-phase LA in ICT-3 LV extension feeder (220KV line-2) at

Malayalapalli substation

1. NTPC to disable high-set of DEFR on the 220 kV lines emanating from their

Ramagundam STPS.

2. NTPC/ TSTRANSCO to provide Line Differential Protection (with or without pilot) on

220 kV Ramagundam – Malayalapalli lines – 1 & 2 & 3.

Pending [with PGCIL

(SR-I)]

11-06-2017

at 19:46hrs

Annexure-C

Page 2 of 52

APTRANSCO Mail Dated 18.12.2018:

1) Bays and lines pertains to PGCIL .

2) ---Completed.

PGCIL (SR-I) mail dated 20.12.2018:

1) PO placed on M/s GE & TD India Ltd on 24.09.2018. Supply of relays will be completed by Jan'2019.

APTRANSCO MAIL DATED 22.01.2019:

Pending [with PGCIL (SR-I)]


PGCIL(SR-1):

This issue of retrofitiing of distance relays with LDP relays in Kurnool(PG) – Kurnool(AP) D/C lines has been discussed with our

management. Our management is seeking approval for the same. You are requested to takeup this LDP issue in next TCC meeting.



management. Our management is seeking approval for the same. You are requested to takeup this LDP issue in next TCC meeting.

PGCIL SR-l Mail dated 15.12.2021

1.Completed

PGCIL -Sr-1 mail dated 17.12.2019:


management. Our management is seeking approval for the same.

SRPC/PCSC may please allow the POWERGRID to book the expenditure in any ongoing/upcoming projects.

PCSC on 18.12.2019:

PCSC forum decided to forward the issue to SRPC TCC meeting

PGCIL-SR-1 mail dated 21.01.2021:

This issue of retrofitiing of distance relays with LDP relays in Kurnool(PG) – Kurnool(AP) D/C lines has been discussed in TCC

meeting. Accordingly order placed on M/s GE for supply and commissioning of relays. Target date: 30.04.2021.


APTRANSCO would extend support and requirements if any ,for the rectification proposed by KPTCL.


It was noted that the original Gooty - Lingapur line got LILOed at BTPS, Alipura, and Ragulapadu. It was also noted that Phase

Discrepancy is being observed in Ragulapadu - Alipira section only. When enquired about the same, KPTCL informed that they

would examine the issue in detail, and would inform the action lan proposed by next PCSC-71 meeting. On this, APTRANSCO was

also asked to render all help required from their side to KPTCL.

APTRANSCO maild dated 30.01.2018:

APTransco world extend required support .

APTRANSCO maild dated 24.04.2018 & 24.05.2018 & 26.06.2018:

AP Transco would extend required support for attending, phase discrepancy issue in ragulapadu-Alipura line by KPTCL.

APTRANSCO Mail Dated 25.07.2018:

To be attended by KPTCL as discussed in 75th PCSC meeting.


Phase mis match issue is to be sorted out jointly by KPTCL/ APTRANSCO/ KPCL.


Attended. Suitable corrections have been made at Alipur Sub station end on the secondary side in order to match phases with that of

Ragalapadu.

02-10-2017 at 02:03

hrs

Tripping of 400 kV

Kurnool(PG) – Kurnool(AP)

line-2

69/III/3APTRANSCO/

PGCIL (SR-I)

1) PGCIL (SR-I) and APTRANSCO to provide for Line Differential Protection as both the

Main protections on 400 kV Kurnool (AP) – Kurnool (PG) lines 1 & 2 lines.

2) APTRANSCO to furnish an action taken report w.r.t. resolving A/R non-operation at

Kurnool-AP end for the subject trippings and configure EL for capturing PDR operation at

their 400 kV Kurnool-AP SS.

KPTCL and APTRANSCO to sort out issues relating to incongruence in denoting R, Y, B

phases of the electric supply on their respective sides.APTRANSCO/ KPTCL69/III/7

Line tripped on B-ph to ground fault. A/R was unsuccessful at

both Kurnool (AP) and Kurnool (PG) ends.

Tripping of 220 kV

Ragulapadu – Alipura line

12-10-2017 at 01:30

hrs

Pending

[with KPTCL ]

Pending [with PGCIL

(SR-I)]

Line tripped on B-Ph to earth fault. A/R was successful at

Regulapadu and breakers at Alipura end got tripped.

Annexure-C

Page 3 of 52

Review Meeting on 20.12.2018:

PCSC forum decided that concrete action in this respect to be initiated in 2 months by KPTCL alongwith APTRANSCO.

APTRANSCO MAIL DATED 22.01.2019:

Pending [with KPTCL ]


KPTCL informed that the work is expected to be completed by August 2019.


Correction is to be incorporated in the primary side, procurement of required materials under progress.


3). Nagzari-Bidnal PLCC link is healthy --- Completed.

1.--- Pending

2. --- Pending


1. & 3. Completed

2. Pending

KPCL mail dated 24-12-2018:

1) --- Completed

2) Proposal will be taken up for replacement of existing PZ1000 relays with new version Numerical Line protection relays having

IEC61850 shortly, after availing necessary admnistrative approval...Pending

3) Completed

KPCL mail dated 23.01.2019:

1. Completed

2. Letter addressed to site to take up the proposal for replacement of PZ1000 line distance relays.

3. Completed

KPTCL Mail dated 14.2.2021

2) Approval from PSDF was received on 31.03.2021. Detailed order is placed on M/s GE T&D Ltd. work will completed by Mar-

2021.

Contract agreement is executed with contractor & drawing approval is completed.

Supply portion is completed


1). COMPLETED


IEC61850. Prepration of specification is under progress.

3) COMPLETED


1) & 3) Completed

2) Budgetary offer obtained for replacement of existing PZ1000 relays with new version Numerical Line protection relays having

IEC61850. Preparation of estimation and specification is under progress.


1) & 3) Completed

2) Replacement of existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 is included in PSDF

Phase-II DPR. Approval of NLDC for DPR is awaited. Further, availing administrative approval for issue of NIT for replacement of

existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 and preparation of estimation and

specification is under progress.


KPCL informed that the work is expected to be completed by December 2019.Complete outage of 220 kV

Nagjheri PH and 220/110 kV

Ambewadi Substation.

KPCL/ KPTCL78/I/2

KPTCL and APTRANSCO to sort out issues relating to incongruence in denoting R, Y, B

phases of the electric supply on their respective sides.APTRANSCO/ KPTCL69/III/7

Tripping of 220 kV

Ragulapadu – Alipura line

12-10-2017 at 01:30

hrs

17-09-2018 at

14:37hrs

1. SLDC/KPTCL to be pro-active in issuing necessary directions that help in expeditious

restoration of the tripped lines based on the prevailing conditions and grid security.

2.KPCL to implement A/R enabled on all 220 kV lines emanating from their 220 kV

Nagjheri PH, with the help of KPTCL, by December, 2018. In the event of non-amenability

of the existing PZ1000 relays in providing A/R feature, KPCL shall take steps to retrofit

them with suitable relays that support A/R.

3. KPTCL to restore PLCC carrier communication on 220 kV Nagjheri – Bidnal line at the

earliest

220kV lines connected to Nagjheri PH got tripped due to

successive transient faults. Running Units #3 and #4 at

Nagjheri got tripped on over frequency protection operation

due to loss of evacuating lines resulting in complete outage of

220 kV Nagjheri. 220 kV Nagjheri being the only source to

220kV Ambewadi station, since 220kV Ambewadi Narendra

line 1&2 were under shutdown during antecedent condition,

tripping of Units at 220 kV Nagjheri resulted in the loss of

supply to 220 kV Ambewadi SS.

Pending

[with KPTCL ]

Line tripped on B-Ph to earth fault. A/R was successful at

Regulapadu and breakers at Alipura end got tripped.

Pending

Annexure-C

Page 4 of 52


1) & 3) Completed


Phase-II DPR. Approval of NLDC for DPR is awaited. However, administrative approval for issue of NIT for replacement of

existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 obtained. Preparation of technical

specification is under progress.


2)Replacement of existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 is included in PSDF

Phase-II DPR. Approval of NLDC for DPR is awaited. NIT issued through e-portal on 16.09.2019. Pre-bid meeting was held on

10.10.2019. Finalising of replies to pre-bid queries is in progress.



Phase-II DPR. Approval of NLDC for DPR is awaited. NIT issued through e-portal on 16.09.2019. Cover-1 opened on 02.12.2019.

Technical evaluation is in progress.



Phase-II DPR. Approval of NLDC for DPR is awaited. NIT issued through e-portal on 16.09.2019. Tender evaluation is in progress.

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:


Phase-II DPR. NIT issued through e-portal on 16.09.2019. Tender evaluation is completed. Approval of NLDC for DPR is awaited

for placing PO on L1 agency.


2) Approval from PSDF was received on 31.03.2021. Detailed order is placed on M/s GE T&D Ltd. work will completed by Dec-

2021


Contract agreement is executed with contractor & engineering work is in progress.

KPCL mail dated 12-10-2021

1. Complled. 2). Action has


2) Approval from PSDF was received on 31.03.2021. Detailed order is placed on M/s GE T&D Ltd. work will completed by Mar-

2021.


Supply portion is completedReview Meeting on 20.12.2018:

1. KPTCL I formed that SPS scheme finalisation shall be completed in one month time --- Pending

KPCL mail dated 24-12-2018:

2) Time delay of operation is not changed. However, the external NCT is used for REF protection against earlier internal NCT for

REF, to avoid tripping due to malopration --- Completed.


1) It shall be reviewd and Implemented by KPCL in coordination with KPTCL.

2)....Completed.


1) It shall be reviewd and Implemented by KPTCL in coordination with KPCL.

KPCL mail dated 10.05.2019 & 25.06.2019 & 30.10.2019:

1) Letter addressed to KPTCL RT dated: 25.03.2019 for review and implementation of SPS at NPH. Reply is awaited.


1. KPTCL informed that Nagjheri SPS has to be studied in the event of configuration changes and outcome of the same will be

intimated soon .

KPTCL Mail dated 12-10-2021

1. Complied , Directions issued. 2). KPTCL is ready to enabling AR for all the lines connecting to NPH. Readiness from KPCL is to

be confirmed. Already AR is put in to service from Hubli end for 3 numbers of lines connecting to Nagzari. 3). To be compled by

KPCL


KPTCL/ KPCL complied

Complete outage of 220 kV

Nagjheri PH and 220/110 kV

Ambewadi Substation.

KPCL/ KPTCL

Triggering incident was B-E fault in 220 kV Nagjheri -

Ambewadi line-1. As per the information received, after

tripping of 220 kV Naghjeri - Ambewadi line-1, 220 kV

Naghjeri Ambewadi line#2 got overloaded. This resulted in

the tripping of Nagjheri Generating Units #3 and 6 on SPS

operation. At the same time, Unit #2 got tripped on REF

operation.

78/I/2

1)KPTCL to examine the reasons for tripping of more than one Unit (Units – 3 & 6) on SPS

operation at Nagjheri PH during subject trippings, and furnish a report on the same along

with remedial action taken to PCSC forum.

2)KPCL to employ a suitable time delay of 50 – 60 msec in operation of REF protection for

the GT of Unit-2 at their Nagjheri PH.

78/II/16Multiple trippings at 220kV

Nagjheri PH

17-09-2018 at

14:37hrs

1. SLDC/KPTCL to be pro-active in issuing necessary directions that help in expeditious

restoration of the tripped lines based on the prevailing conditions and grid security.

2.KPCL to implement A/R enabled on all 220 kV lines emanating from their 220 kV

Nagjheri PH, with the help of KPTCL, by December, 2018. In the event of non-amenability

of the existing PZ1000 relays in providing A/R feature, KPCL shall take steps to retrofit

them with suitable relays that support A/R.

3. KPTCL to restore PLCC carrier communication on 220 kV Nagjheri – Bidnal line at the

earliest

220kV lines connected to Nagjheri PH got tripped due to

successive transient faults. Running Units #3 and #4 at

Nagjheri got tripped on over frequency protection operation

due to loss of evacuating lines resulting in complete outage of

220 kV Nagjheri. 220 kV Nagjheri being the only source to

220kV Ambewadi station, since 220kV Ambewadi Narendra

line 1&2 were under shutdown during antecedent condition,

tripping of Units at 220 kV Nagjheri resulted in the loss of

supply to 220 kV Ambewadi SS.

31-08-2018

at 11:49 hrs

Pending

Annexure-C

Page 5 of 52

83/I/6


1) Revised settings is received from CEE RT & R&D vide e-mail dated:08.06.2021 and requested to conduct

the functionality check of the SPS, in co-ordination with RT Division Hubli after revision of limit. Accrodingly,

SE(E)N vide letter dated:12.06.2021 addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the

necessary settings and check funtionality of the same.

CEERT, KPTCL vide e-mail dated:25.06.2021 has informed that the NPH Exbus generation limit has been

modified from 600MW to 300MW in SPS logic built at NPH and no other changes are made in the SPS logic

The said changes are made on 25th June 2021 at 12pm. SPS functionality is running successfully after

loading the new configuration. The Point is closed.

2) Completed.

KPCL Mail dated 14.02.2022

1) Revised settings is received from CEE RT & R&D vide e-mail dated:08.06.2021 and requested to conduct

the functionality check of the SPS, in co-ordination with RT Division Hubli after revision of limit. Accrodingly,

SE(E)N vide letter dated:12.06.2021 addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the

necessary settings and check funtionality of the same.

CEERT, KPTCL vide e-mail dated:25.06.2021 has informed that the NPH Exbus generation limit has been

modified from 600MW to 300MW in SPS logic built at NPH and no other changes are made in the SPS logic

The said changes are made on 25th June 2021 at 12pm. SPS functionality is running successfully after

loading the new configuration.

83/II/9Tripping of 400 kV GUTTUR -

NARENDRA -1

10-03-2019 at

18:03hrs

Line tripped on operation of overvoltage stage-1 protection at

Guttur end and DT received at Narendra end. Voltages at

Guttur end: Vr-254kV, Vy-252kV, Vb-246kV. As per voltage

grading, 400kV Guttur Narendra line-2 should trip first.

PGCIL (SR-II) to submit action plan regarding replacement of CT’s for 400Kv Guttur

Narendra line -1 at Guttur end. PGCIL (SR-II) to sort out the time sync issues in DR and EL

at Narendra end.

PGCIL (SR-II)/ KPTCL


Line belongs to PGCIL(SR-2)

Review meeting on 27.06.2019:

PGCIL(SR-II) informed that R & Y ph CVT replaced on 25.05.2019. Time syncronisation has to be attended by KPTCL.

PGCIL (SR-2) mail dated 02.07.2021:

R & Y ph CVT replaced on 25.05.2019,Pending with KPTCL.

Pending with KPTCL

TANTRANSCO mail dated 26.07.2019:

1 & 2.Inbuilt LBB function will be enabled in the new distance relays.

3. will be ensured.

4.230kV Kilpauk was operated radially for avoid overloading in the adjacent feeders due to cable fault in the area.Normally all

feeders are operated as grid feeders.


1. LBB wiring set right and operation of the same has been verified for its healthiness. -- Completed

2. Since the CBs and the Control & Relay Panels (CRP) are very old and commissioned during 1993. The Distance relays even

though are numerical due to ageing its display and resetting keys are faulty. Hence it is proposed to replace the CBs & CRPs with

new CBs and Protection relay panel with SAS. A.R will be put into service after replacing the CB & CRP.

3. Time synchronisation of Protection relays is being carried out . The work is under progress.

KPTCL/ KPCL complied

Pending (2)84/I/1

Triggering incident was B-E fault in 220 kV Nagjheri -

Ambewadi line-1. As per the information received, after

tripping of 220 kV Naghjeri - Ambewadi line-1, 220 kV

Naghjeri Ambewadi line#2 got overloaded. This resulted in

the tripping of Nagjheri Generating Units #3 and 6 on SPS

operation. At the same time, Unit #2 got tripped on REF

operation.

1)KPTCL to examine the reasons for tripping of more than one Unit (Units – 3 & 6) on SPS

operation at Nagjheri PH during subject trippings, and furnish a report on the same along

with remedial action taken to PCSC forum.

2)KPCL to employ a suitable time delay of 50 – 60 msec in operation of REF protection for

the GT of Unit-2 at their Nagjheri PH.

Triggering incident was Y phase to Earth fault in 220 kV

NCTPS Tondiarpet line-2. Due to mal-operation of LBB

protection (of Tondiarpet line-2) at NCTPS end, all the

connected elements of bus zone-3 got tripped. Due to loss of

evacuating lines, running units at NCTPS unit#1 and 2 got

tripped.

18-05-2019 at 04:39

hr.

Complete outage of 230kV

NCTPS Generating Station of

TANGEDCO

TANGEDCO/ TANTRANSCO

1.TANTRANSCO may take immediate measures to attend the problem in LBB wiring that

is extending trip during A/R within one month.

2. TANTRANSCO is recommended to send a detailed report regarding the A/R status

(availability /enabling)on all lines emanating from 230kV NCTPS GS and enable A/R in all

lines emanating from 230kV NCTPS GS.

3.TANGEDCO in coordination with TANTRANSCO may take definite measures to ensure

time synchronization of all relays with GPS signal at NCTPS end and remote ends at the

earliest.

4. It was also suggested that possibility of backing down of generation, in the event of

unavailability of many feeders, in particular when radial feeders only are in service, may be

looked at.

78/II/16Multiple trippings at 220kV

Nagjheri PH

31-08-2018

at 11:49 hrs

Annexure-C

Page 6 of 52

TANTRANSCO mail dated 20.05.2020 & 15.06.2020

1. complied .




3. GPS commissioned


1. complied .




3. GPS commissioned

4. TANGEDCO to reply - Pending

TANGEDCO mail dated 11.11.2020:

4. House Load operations are available in all the 3 units of NCTPS - 1 .

Generators can able to supply their own auxiliary load alone during this period and they can be synchronised to the grid when the

situation is

stable. But due to sudden change in turbine and boiler parameters

house load operation could not be possible at all times (Old Turbine and Boiler control logic). (Feeders in Bus-Section I & II are

already in tripped condition and the whole generation is fed through Bus-Section - III , due to the tripping of this, load evacuation

problem got arise and consequent Unit tripping are happened) - Complied

Note: 1) On that day Unit - II is in house load for 7 Mins, Unit - I is in house load for 1 Min and then both the units are hand tripped

due to un controlled turbine and boiler parameters.

2) Unit-III turbine got tripped due to overspeed.




new CBs and Protection relay panel with SAS. A.R will be put into service after replacing the CB & CRP. -- Pending


1, 3, 4. Complied

2. . Since the CBs and the Control & Relay Panels (CRP) are very old and commissioned during 1993. The Distance relays even




3. Complied- GPS commissioned.

TANTRANSCO email dated 28.08.2021:

1. Complied .




TANTRANSCO mail dated 28.05.2021

1. Complied .




3. GPS commissioned


Since the CBs and the Control & Relay Panels (CRP) are very old and commissioned during 1993. The Distance relays even though

are numerical due to ageing its display and resetting keys are faulty. Hence it is proposed to replace the CBs & CRPs with new CBs

and Protection relay panel with SAS. A.R will be put into service after replacing the CB & CRP.

TANTRANSCO: mail dated 28.12.2021




85/II/26Tripping of 400kV Vemagiri-

GMR line-1&2

14-06-2019 at 09:33

hrs

Line-1 tripped on Y-Phase to earth fault due to Y-Phase LA

failure at Vemagiri end. Line-2 tripped at GMR end only

1. APTRANSCO is recommended to submit Equipment failure report (LA failure) to CEA.

2.GMR is recommended to submit a report regarding tripping of 400kV Vemagiri-GMR

line-2 at GMR end along-with the related tripping files.APTRANSCO/ GMR


1. Equipment (LA failure) Failure report submitted to CEA on 12.07.19.

---Completed

2. Pending

Pending 86/II/7

88/IV/4Tripping of 220kV Chillakallu

Suryapet line-1

17-10-2019 at 13:30

Hr.

Triggering incident was Y phase to B phase fault in the line.

At Chillakallu end, as per the report submitted it is mentioned

that Zone-1 distance protection operated. However, DR is not

available to verify the same. At Suryapet end, Zone-2 distance

protection operated and carrier was not received. Failure of

carrier aided protection at Suryapet end needs review.

1. APTRANSCO is recommended to submit Equipment failure report (LA failure) to CEA.

2.GMR is recommended to submit a report regarding tripping of 400kV Vemagiri-GMR

line-2 at GMR end along-with the related tripping files.TSTRANSCO,/ APTRANSCO

TSTRANSCO mail dated 11.02..2020:

At our end MRT & Telecom wing are ready to carry out end to end testing.

Waiting for confirmation from APTRANSCO end to carry out testing.


a) & b) End to end testing is carried out and A/R function is kept into service.

TSTRANSCO mail dated 04-10-2021:

TSTRANSCO: There is problem with the GPS and is being couriered to Gujarat for rectification.

TSTRANSCO Mail dated 10.02.2022.

TSTRANSCO: Time synchronization is done on 25-11-2021 after receipt of GPS from Gujarat.

Pending KPTCL-DR configuration ?

Pending (2)84/I/1

Triggering incident was Y phase to Earth fault in 220 kV

NCTPS Tondiarpet line-2. Due to mal-operation of LBB

protection (of Tondiarpet line-2) at NCTPS end, all the

connected elements of bus zone-3 got tripped. Due to loss of

evacuating lines, running units at NCTPS unit#1 and 2 got

tripped.

18-05-2019 at 04:39

hr.


NCTPS Generating Station of

TANGEDCO

TANGEDCO/ TANTRANSCO

1.TANTRANSCO may take immediate measures to attend the problem in LBB wiring that

is extending trip during A/R within one month.

2. TANTRANSCO is recommended to send a detailed report regarding the A/R status

(availability /enabling)on all lines emanating from 230kV NCTPS GS and enable A/R in all

lines emanating from 230kV NCTPS GS.

3.TANGEDCO in coordination with TANTRANSCO may take definite measures to ensure

time synchronization of all relays with GPS signal at NCTPS end and remote ends at the

earliest.

4. It was also suggested that possibility of backing down of generation, in the event of

unavailability of many feeders, in particular when radial feeders only are in service, may be

looked at.

Annexure-C

Page 7 of 52

88/IV/4Complete loss of supply at 220

kV Kolar, 220 kVMalur and

220 kV Sarjapur stations.

16-01-2020 at 09:58

Hr.

• Triggering incident was Y-phase jumper cut in 220 kV Kolar

(KAR) – Kolar (PG) line-1.

• 220 kV Kolar (KAR) – Kolar (PG) Line-2 tripped at Kolar

(KAR) end only.

• There was complete loss of supply at 220 kV Kolar, Malur

and Sarjapur stations.

i. PGCIL (SR-2) to disable Broken conductor trip and enable Broken conductor alarm.

ii. KPTCL to configure all DR digital channels in relay DR and submit the SPS scheme

implemented at 220 kV Kolar (KAR) SS.PGCIL (Sr-2)/ KPTCL


2. Logic implemented for SPS provided at 220kV Kolar Sub station is already mailed to SRPC/SRLDC.


Broken conductor is only kept as alarm.


KPTCL-DR Configuration Done. Kolar SPS logic is furnished to SRPC/SRLDC.

Pending KPTCL-DR configuration ?

90/II/17Tripping of 400kV Guttur

–Hiriyur Line-2

15-03-2020 at

18:03Hr.

Line tripped on operation of OV St-1 protection operation at

Hiriyur end and was holding at Guttur end. From DR of

Hiriyur end, voltages observed are: Vr-251kV, Vy-248kV and

Vb-248kV. Non tripping of line at Guttur end needs review.

PGCIL-SR-2 to configure DR and EL at Hiriyur end for the subject line for DT send and

DT receive signal.

For the subject line, the following shall be carried out by PGCIL-SR-2 in coordination

with KPTCL and revert back to the forum:

i. End-to-end testing for DT/ permissive& other signals to be ensured by testing at both the

ends.

ii. Healthiness of PLCC system components (hardware and software) at both the ends shall

be checked and faulty components shall be repaired/ replaced.

PGCIL (SR-2)/ KPTCL


End to end testing is yet to be carried out.


DT send for OV protection and DT receive Configured as per the requirement.

PGCIL (SR-2) mail dated 04-10-2021

End to end hiriyur testing will be done as per KPTCL shutdown


End to End test has een done. Recent end to end test date 13.08.2021 for Guttur-Hiriyur lines.

Pending

90/V/1220kV KTPS-Lower Sileru line-

1 and 220kV KTPS V- Lower

Sileru line-2

10 -02-2020 at

11:34 Hr.

05-03-2020 at 12:00

Hr.

07-03-2020 at 13:25

Hr.

11-03-2020 at 15:01

Hr.

15-03-2020 at 12:04

Hr.

18-03-2020 at 12:25

Hr.

22-03-2020 at 10:50

Hr.

08-02-2020 at

12:35 Hr.

15 -02-2020 at

13:29 Hr.

16-02-2020 at

11:54 Hr.

22-03-2020 at 11:16

Hr.

27-03-2020 at 12:05

Hr.

12-04-2020 at 12:19

Hr.

V. Frequent tripping of 220kV KTPS-Lower Sileru line-1 and

220kV KTPS V- Lower Sileru line-2 during February 2020 to

April 2020.

ATRANSCO in coordination with TSTRANSCO to ensure frequent patrolling and proper

maintenance of ROW by attending all tree clearance issues.APTRANSCO/ TSTRANSCO


KTS-LSL is made LILO at Asupaka SS.

Frequent patrolling is being carried out from TSTRANSCO end.


TSTRANSCO

220kV KTS-Lower Sileru line is made LILO to Asupaka SS and the line length of 220kV Asupaka-Lower Sileru is 98.93kMs. Out

of which TSTRANSCO jurisdiction is only 17.5kMS.

220kV KTSV-Lower Sileru line length is 114.7kMS. Out of which TSTRANSCO jurisdiction is only 25kMs.

For the above lines, most of the faults are not under TSTRANSCO jurisdiction. However frequent patrolling of the line is carried

from TSTRANSCO end.

Pending with APTRANSCO.

90/VI/1Tripping of 220kV KTPS –

Nunna line

05-03-2020 at 13:44

Hr.

06-04-2020 at 13:39

Hr.

08-04-2020 at 16:53

Hr

10-04-2020 at 08:28

Hr

11-04-2020 at 15:03

Hr

18-04-2020 at 15:50

Hr

Frequent Tripping of 220kV KTPS – Nunna line during

February 2020 to April 2020

ATRANSCO in coordination with TSTRANSCO to ensure frequent patrolling and proper

maintenance of ROW by attending all tree clearance issues.APTRANSCO/ TSTRANSCO


Frequent patrolling is being carried out from TSTRANSCO end.

TSTRANSCO mail dated 04-10-2021

TSTRANSCO: Frequent patrolling is carried out from TSTRANSCO end.

APTRANSCO Pending

91/II/1Tripping of 220kV-

PAVAGADA-KSPDCL line-4

04-04-2020 at

08:46Hrs

• Triggering incident was Y N fault in 33kV cable no.3 of

KSPDCL 220/33kV SS-4.

• Cable got tripped on operation of Overcurrent protection.

• At the same time, 220kV Pavagada KSPDCL line-4 got

tripped only at Pavagada end on operation of DEF protection.

i. PGCIL(SR-2) to intimate PCSC forum regarding OEM observations and RM suggested

regarding DEF operation by Main-2 Siemens relay at Pavagada end.

ii. KSPDCL to check PLCC and investigate the reason for non-receipt of DT at their end.

Time synchronisation of relays with GPS clock at KSPDCL SS need to be ensured.

PGCIL(Sr-2)/ KSPDCLPGCIL mail dated 02.07.2021:

OEM suggested for firmware upgradation same was completed on 01.05.2021.Pending-KSPDCL

91/II/5Tripping of 220kV-

PAVAGADA-KSPDCL line-3

19-04-2020 at

15:23Hrs

• Triggering incident was B N fault in 33kV cable of

KSPDCL 220/33kV SS-3.




i. PGCIL(SR-2) to intimate PCSC forum regarding OEM observations and RM suggested

regarding DEF operation by Main-2 Siemens relay at Pavagada end.

ii. KSPDCL to check PLCC and investigate the reason for non-receipt of DT at their end.

iii. Time synchronisation of relays with GPS clock at KSPDCL SS need to be ensured.

PGCIL(Sr-2)/ KSPDCLPGCIL mail dated 02.07.2021:

OEM suggested for firmware upgradation same was completed on 01.05.2021.Pending-KSPDCL

91/II/13Multiple Tripping in

220kV/33kV KSPDCL SS 4

09-05-2020 at

19:08Hrs

• Triggering incident was B ph Bus-2 PT failure at 220kV

KSPDCL SS no.4.

• Bus-2 BBP operated resulting in the tripping of all the

elements connected to Bus-2 at 220kV KSPDCL SS no.4.

• At the same time, RYBG fault occurred at 33kV cable

feeder no.6 of KSPDCL 220/33kV SS-3.




i. PGCIL(SR-2) to intimate the forum regarding OEM observations and RM suggested in

respect of DEF operation of Main-2 Siemens relay at Pavagada end.

ii. PGCIL(SR-2) to check the zone settings of Pavagada – KSPDCL line, since it tripped in

Zone-1 for a fault in remote SS.

iii. KSPDCL to check PLCC and investigate the reason for non-receipt of DT at their end.

iv. Time synchronization of relays with GPS clock at KSPDCL SS need to be ensured.

PGCIL(Sr-2)/ KSPDCL


ii) Sufficient time delays for NPS protection is adopted based on OEM recommendations for HT equipments. This point may be

dropped.

iii) It will be configured during next shut down of lines.

PGCIL mail dated 02.07.2021:

OEM suggested for firmware upgradation same was completed on 01.05.2021.

PGCIL mail dated 04-10-2021:

Not pending with PGCIL SR2

Pending with KSPDCL

Annexure-C

Page 8 of 52

91/II/19Tripping of 400kV

Ramagundam – Dichipalli line

22-05-2020 at

12:39Hrs

• Triggering incident was B N fault in the line.

• At Ramagundam end, fault was sensed in Zone-1.

• Initially B pole breaker got opened, subsequently R and Y

poles also got opened due to occurrence of fault in Y phase.

• At Dichipalliend,fault was sensed in Zone-1, B pole got

opened and when there was subsequent fault in Y phase,

instead of 3 ph trip, there was A/r attempt

i. TSTRANSCO to check A/R scheme at Dichipalli end and sort out the issue with

unwarranted reclosing of Main CB.

ii. NTPC and TSTRANSCO to sort out time sync issue of relays at both ends of the line.TSTRANSCO/ NTPC (Rmgdm)


i. LC was availed on 19-08-2020 and A/R scheme is verified. Wiring for 3phase A/R is removed.


TSTRANSCO:

Problem is with the GPS and it is to be sent to Germany for rectification. Due to present COVID condition it is being delayed.


TSTRANSCO: Time synchronization is done with spare GPS on 20-04-2021

Pending Time sync??

91/II/21Tripping of 400Kv

NarnoorSrisailam Left Bank

26-05-2020 at

16:32Hrs

• Triggering incident was R N fault in the line.

• Line tripped only at Narnoor end on receipt of DT.

• From DR of Narnoor end, Zone-2 pickup was observed.

i. For the subject line, APTRANSCO in coordination with TSGENCO to carry out the

following and revert back to the forum:

a. End-to-end testing for DT/ Permissive& other signals to be ensured by testing atboth the

ends.

b. Healthiness of PLCC system components (hardware and software) at both theends to be

checked and faulty components to be repaired/ replaced.

APTRANSCO/ TSGENCO

TSGENCO: mail dated 09.12.2021

TSGENCO:

a. End to end PLCC test was carried out on 22.10.2020 and ensured all communication signals found normal.

b. Checked healthiness of PLCC system and found normal.

Pending

91/III/7

Tripping of 220kV

Regulapadu –

Alipur line

12-04-2020

at 07:07Hrs

• Triggering incident was B -N fault in the line.

• At Alipur end, line tripped on operation of Z1 distance

protection and A/r not operated.

• At Regulapadu end, it is mentioned that A/r operated.

However, the same couldn't be verified since DR at

Regulapadu end is not submitted.

i. APTRANSCO to submit complete DR clearly showing A/R operation at Regulapadu end.

ii. KPTCL to expedite resolving of phase mismatch issue at Alipur and subsequently enable

A/R in the line at Alipur endAPTRANSCO/ KPTCL


Attended. Suitable corrections have been made at Alipur Sub station end on the secondary side to match phases with that of

Ragalapadu.

Pending with

APTRANSCO.

91/III/14

Tripping of 220kV

Chillakallu-

Pulichintala

01-05-2020

at 02:30Hrs

18-05-2020

at 16:27Hrs

• Triggering incident was R phase to Earth fault in the line.

• Line tripped only at Pulichintala end on operation of Zone-1

distance protection.

• A/r not operated at Pulichintala end

i. APTRANSCO and TSGENCO to ensure proper line clearances on the subject line.

ii. TSGENCO to enable A/R for the subject line at Pulichinthala end at the earliest and

inform PCSC forum.APTRANSCO/ TSGENCO Yet to be informed Pending with NLCIL

91/III/16

Tripping of 220KV

KTPS-

NUNNA line

05-05-2020

at 13:05Hrs


• At KTPS end, A/r is not in service and line tripped on

operation of Zone-2 distance protection.

• At Nunna end, Zone-1 operated and A/r not operated

i. TSGENCO to submit report regarding failure of carrier aided protection at KTPS end and

to make all efforts to put A/R in service.

ii. APTRANSCO to submit report regarding A/R non-attempt at Nunna end for the subject

line.

APTRANSCO/ TSGENCO

APGENCO mail dated 16.06.2021:

Implementation of A/R at KTPS end is under progress and will be communicated to SRPC after implementation.

TSGENCO mail dated 02.11..2021:

Auto Reclosure function for 220kV KTPS-Nunna feeder at KTPS end was enabled and tested successfully on dt.05.07.2021. After

commissioning of A/R at 220kV KTPS-Nunna feeder on 05.07.2021, certain descripencies with regard to Carrier Aided protection

was observed and the same was communicated to the Firm as the Relay is under warranty period. Accordingly, the firm has deputed

the service Engineer on 20.09.2021, and resolved the issues of A/R function.Hence, it is requested to drop the point

Pending- TSGENCO to

furnish report on failure

of carrier aided

protection at KTPS.

APTRANSCO to submit

report regarding A/R non-

attempt at Nunna end for

the subject line.

92/I/2Complete outage of 220/33kV

KSPDCL SS-3

25-06-2020 at 02:43

Hr.

• Triggering incident was tripping of 220kV Pavagada -

KSDPCL3 line due to overvoltage at 220kV Pavagada end.

• Asthe only connected feeder tripped, there was complete

outage at 220/33kV KSDPCL SS-3. Solar generation was not

there, since the event happened during night hours.

i. KSPDCL to share the value of real and reactive power flow through Pavagada KSPDCL

lines during the incidence.

ii. PGCIL (SR-2) to arrange for testing to ensure healthiness of communication channel. KSPDCL/ PGCIL (Sr-2)


Communication channel tested on 24.04.2021and found ok at pavagada end .Pending-KSPDCL

92/II/1Multiple Tripping in 220kV

Nunna SS of APTRANSCO

03-06-2020 at 14:01

Hr.

• Triggering incident was failure of B phase LA of 220kV

Nunna- Gunadala line-2 (connected to 220kV Bus-2) in

220kV Nunna station.

• Due to breaker problem in 220kV Nunna- Gunadala line at

Nunna end, LBB of Bus-2 operated resulting in tripping of all

elements connected to 220kV Nunna Bus-2.

• 400/220kV ICT-3 got tripped on operation of backup OC

protection.

i. APTRANSCO to submit the line DR at Gunadala end for the tripping of 220kV Nunna –

Gunadala line-2 and submit report regarding non-operation of CAT Zone-2 at Gunadala end.

ii. APTRANSCO to ensure time synchronization of relays at Nunna end.

iii. PGCIL (SR-1) to ensure proper naming of digital signals in the DR of 400/ 220kV ICT-3

at Vijayawada.

APTRANSCO/ PGCIL(Sr-1)

PGCIL-SR-1 mail dated 21.01.2021:

iii.PGCIL(SR-1): DR naming corrected as per scheme and DR standardized for ICT-3 DOC & EF relay at Vijayawada SS on

03.07.2020. - Completed

Pending [ with

APTRANSCO]

92/III/4 , 92/III/6, 92/III/8Tripping of 220kV Chillakallu -

Pulichintala line

17-06-2020 at 01:21

Hr.

• Triggering incident was R phase to Earth fault in the line.

Line tripped on operation of Zone-1 distance protection at

both the ends.

• A/R not operated at both ends.

i. TSGENCO to enable A/R at Pulichintthala SS at the earliest.

ii. APTRANSCO and TSTRANSCO to ensure proper ROW for the line.TSGENCO/ TSTRANSCO/

APTRANSCO


ii. Thorough patrolling is carried out by TSTRANSCO on this feeder.


TSTRANSCO: Frequent patrolling is carried out from TSTRANSCO end.

Pending with

TSGENCO/APTRANS

CO

Annexure-C

Page 9 of 52

93/I/5

Complete outage of 220

kVNagjheri GS,220

kVAmbewadi, 220

kVBidnal&220 KVHubli

31-08-2020 at 17:12

Hr.

In the antecedent condition 220 kVNarendra Bus-1 and Bus-2

were under planned shutdown for maintenance works.

• 220 kVNagjheri - Kodasalli D/C and 220 kVHubli - Sirsi

lines were kept open in the antecedent for operational

purpose. 220 kVBidnal - Harti line-2 was in idle charged

condition from Bidnal end.

• Initially three units were in service at Nagjheri with 400MW

generation. As reported, under these conditions, Unit#4 at

Nagjheri was brought in, which resulted in overloading of the

connected 220 kV lines and the lines tripped on overcurrent

protection.

• Running units at Nagjheri also tripped. These resulted in

complete outage of 220 kV Nagjheri, 220kV Hubli, 220 kV

Bidnal and 220 kV Ambewadi stations.

i. KPTCL to take up with Karnataka SLDC to ensure that Grid Disturbances on account of

operational issues do not occur in Kali (Nagjheri) complex, and be watchful of the

prevailing grid conditions before scheduling/rescheduling of generation at Nagjheri

complex.

ii. KPTCL to provide updated status of A/R of all 220kV lines at Nagjheri complex.

iii. KPCL to provide centralized DR downloading facility at their Nagjheri GS, and sort out

the issues in downloading DR’s from various protection relays at their Nagjheir GS.

KPCL/ KPTCL


iii) Will be taken during SCADA implementation works.


i. Communicated to CEE,SLDC - Completed

ii. At Hubli and Bidnal Sub stations, KPTCL is ready for enabling AR for Nagzari Connectted lines. Coordination required from

KPCL. Confirmation regarding readiness by KPCL for enabling AR for Hubli and Bidnal connected lines at Nagzari end is awaited.

At Ambewadi Sub station, Circuit Breakers of Nagzari lines have to be replaced, work is already taken up. Once Circuit Breaker

replacement work is completed Ambewaadi end will be ready for enabling AR for Nagzari connected lines. - Pending


iii) As per the directions of TESG of NLDC i..e. Numerical relays are being

provided for all Units and Lines, the proposal of providing Disturbance recorder is excluded from DPR submitted for availing funds

from PSDF - Issue may be

dropped. --- The point may be dropped.




from PSDF - Issue may be

dropped. --- The point may be dropped.


i. Communicated to SLDC 2. KPTCL end all lines are ready for enabling AR, clearence awaited from Nagzari PH. Replacement of

PZ 1000 Main -1 relay is pending at Nagzari.




complied

93/I/6Complete outage of 230 kV

Hosur SS of TANTRANSCO

05-09-2020 at

01:19Hr.

• Triggering incident was failure of Y ph CT of 230kV Hosur-

TN - Shoolagiri line-2.

• Bus-1 BBP operated and all the elements connected to Bus-

1 tripped at 230 kV Hosur-TN end.

• There was complete loss of supply at 230 kV Hosur-TN

SS,since there is single bus operation at 230 kV Hosur-TN

SS.

i. TANTRANSCO to implement Main and Transfer bus or Double Bus scheme at 230/

110kV Hosur_TN substation. Time synchronization of relays of the SS need to be ensured.

ii. TANTRANSCO to submit detailed report regarding discrepancy pointed out in BBP

operation and second B-E fault in 230kV Hosur_TN – Hosur_PG lines. Further, till

numerical relays are provided for BBP protection, steps shall be taken to record BBP

operation in line DRs.

iii. TANTRANSCO to submit equipment failure report to CEA in respect of the failed Y-ph

CT at 230kV Hosur_TN SS.

iv. PGCIL-SR2 to submit a report regarding instantaneous tripping of 230kV Hosur-TN –

Hosur PG line-2 at Hosur-PG end during second B-E fault during A/R dead time, in spite of

detecting the fault in Zone-2 (carrier not received).

TANTRANSCO/ PGCIL (Sr-2)


Will be ensured

TANTRANSCO mail dated 28.04..2021:

The recommendation of 1 & 2 will be complied.

Report will be sent to CEA

TANTRANSCO email dated 28.05.2021:

Hosur R&M work is now under progress. The recommendation of 1 & 2 will be complied.


TANTRANSCO mail dated28.05..2021:


Report will be sent to CEA.


Transplay of the fault carried out and observed similar behaviour of the relay. Relay overeach observed. Reistance reaches were

suitabley reduced . However, to avoid further incidents, POR scheme is suggested to be implemented at both ends. Necessary request

is given to TANTRANSCO.

TANTRANSCO mail dated 17.07.2021:, 06-10-2021



As Such there is no overreach noticed at Hosur TN end. AR sucessful at both ends during the tripping on 30.06.2021 @ 11:57

hrs.Hence POR scheme is not necessary.



Pending

93/I/7


Lingasugur, 220 kV Bagewadi

stations of KPTCL and 220 kV

Alamatti station of KPCL

22-09-2020 at 13:05

Hr.

• Triggering incident was tripping of 220 kVLingasugur -

RTPS line-1 on distance protection due to fault in the line.

After about 4minutes, 220 kVLingasugur - Shahpura and 220

kVLingasugur - RTPS line-2 tripped on overcurrent

protection.

• As reported, after tripping of these lines, there was cascaded

tripping of the other 220 kV lines connected at Lingasugur

station, resulting in complete loss of supply at 220

kVLingasugur station.

• During the event, 220 kVBagewadi station and 220 kV

Alamatti station were also affected

i. KPTCL to take up with Karnataka SLDC to ensure that necessary pre-emptive steps such

as reduction of RE generation on tripping of evacuating lines are taken in order to avoid

cascade tripping of lines on overloading.

ii. KPTCL and KPCL to enable A/R on all 220kV lines in RTPS-Lingasugur complex.

KPCL/ KPTCL


ii) A/R is ready at RTPS end except sedam-1, Lingasugur-3.

Provision has been made for installation of Wave traps for the Sedam-1, Lingasugur-3 under PSDF -II scheme & awaiting for

approval from PSDF for placing order on L1 bidder


i. Communicated to CEE,SLDC

ii. At Lingasugur and Mallat end KPTCL is ready for enabling AR for RTPS connectted lines. Coordination required from KPCL.

Confirmation regarding readiness by KPCL for enabling AR for Lingasugur and Mallat connected lines at Nagzari end is awaited.


ii) A/R is ready at RTPS end except sedam-1,2 and Lingasugur-3 lines.

Provision has been made for installation of Wave traps and upgradation of Main 1 numerical protection line relays from REL 511

(which is absolete) to latest version for Sedam-1,2 and Lingasugur-3 and for all remaining lines including bus coupler under PSDF -

II scheme.

Approval from Nodal Agency for PSDF fund was recieved on 31.03.2021. Awaiting HO approval for placing LOA on L1 bidder.


ii) A/R is ready at RTPS end except sedam-1,2 and Lingasugur-3 lines.

Provision has been made for installation of Wave traps and upgradation of Main 1 numerical protection line relays from REL 511

(which is absolete) to latest version for Sedam-1,2 and Lingasugur-3 along with for all remaining lines including bus coupler under

PSDF -II scheme. Approval from Nodal Agency for PSDF fund was recieved on 31.03.2021.

Obtained HO approval for placing LOA on L1 bidder. LOA has been placed on L1 bidder M/s G E T & D on dated 09.06.2021 and

work is in progress.


ii). AR is put in to service at Lingasugur end

Pending

Annexure-C

Page 10 of 52

93/II/1Tripping of 400 kV Bus-2 at

400 kV Yelahanka SS of

PGCIL-SR2

03-08-2020 at 17:32

Hr.

• During antecedent conditions, ICT#2 at Yelahanka was

under outage since 09:09Hr. due to AMP works. As per the

information received, while charging ICT#2 at 17:36Hr., Bus-

2 BBP operated due to failure of R-phase bus isolator of

ICT#2.

• This resulted in the tripping of all the elements connected to

Bus-2 along with bus coupler.

i. PGCIL SR-2 to share the findings of the OEM on VFT over voltage referred to and

remedial measures thereof.

ii. KPTCL to review & correct Zone settings on 400 kV Nelamangala – Yelahanka line at

Nelamangala end.

iii. KPTCL to ensure time synchronization of relays at Nelamangala SS.

PGCIL(Sr-2)/ KPTCL


ii. At Nelamangala Sub station, Settings for M-I and M-II relays of Yelahanka line are implemented considering protected line length

as 38.9km. As per the discussion had during 93rd PCSC meeting, the actual length of this line is ascertained using offline fault

locator. According to offline fault locator readings length of the protected line is 41.7km. In view of the above existing settigs at

Nelamangala end is not reviewed. For taking further action in this regard, measurement of actual positive and zero sequence

impedances of the line is envisaged. As test kit for measuring the sequence impedances of the lines is not available with KPTCL,

assistance of Powergrid is requested by KPTCL.


Reply awaited.


OEM reply awaited.

PGCIL mail dated 04-10-.2021:

OEM reply awaited.

Pending

93/V/1Frequent Tripping of I. 220

kVAsupaka – Lower Sileru lineAug - September 2020

220 kV Asupaka – Lower Sileru line tripped many times

during August - September 2020. It has been reported that

Auto reclose function at 220 kV Lower Sileru is kept out of

service and same needs to be reviewed. Recurring non-

operation of A/rand keeping A/r out of service may be

elucidated by APTRANSCO/TSTRANSCO.

i. APTRANSCO and TSTRANSCO to maintain proper right of way for the line by ensuring

proper tree clearances.

ii. APGENCO to ensure DR time scale to be at least 2.5 sec to verify successful A/R.

APTRANSCO/ TSTRANSCO/

APGENCO

APGENCO mail dated 23.04.2021:

As per 93 PCSC recommendation DR time was changed to 2.5 sec in both the Main-I and Main-II relayson 28.01.2021.


TSTRANSCO:

A/R is in service on the feeder.

Frequent patrolling is being carried out on the feeder.

Pending with

APTRANSCO.

95/I/6


Edamon SS and 220 kV

Sabarigiri GS of KSEBL

29-01-21

11:42 hrs.

Triggering incident was operation of 220kV BBP of Bus-1

and Bus-2 at Edamon end during relay testing and all the

elements connected to 220kV Edamon SS got tripped. At the

same time, 220kV Sabarigiri GS connected lines also got

tripped resulting in loss of evacuation at 220kV Sabarigiri GS.

Details are awaited.

i.KSEBL to strictly follow SOP while performing all maintenance works in switchyards.

ii.KSEBL to review and revise the zone settings at Edappon and Kundara SS for 220kV

Edamon connected lines, since it was observed to trip in Zone-1 for fault in remote end.

Similarly, DPR Zonal settings at Ambalamugal for 220kV Sabarigiri – Ambalamugal shall

also be reviewed and revised.

iii. TANTRANSCO, in coordination with KSEBL, to review the DPR Zonal settings at

Theni end for 220 kV Sabarigiri – Theni line.

KSEBL/TANTRANSCO

KSEBL Mail dated 05.02.2022.

i)SOP being followed strictly.....Completed

ii) Relay settings at Kundara and Edappon has been reviewed by the KSEBL protection committee and corrections effected wherever

required

iii)pending

Pending

92/III/3Tripping of 220kV Asupaka -

Lower Sileru line-1

09-06-2020 at 16:07

Hr.

• Triggering incident was B-N fault in the line. At Asupka end,

line tripped on operation of Zone-1 distance protection.

• At Lower Sileru end, line tripped on operation of Zone-3


• A/r not operated at both the ends.

APGENCO to enable A/R at Lower Sileru end for the line. APGENCO

APGENCO mail dated 23.04.2021::

Auto reclose of Asupaka-Lower Sileru -I feecder kept ON position at Lower Sileru end from 02.11.2020 in coordination with

Asupaka end.

100/II/7Tripping of 220 kV ASUPAKA

- LOWER_SILERU-1

20-Jan-2022 22:48:00

hrs

As per the report submitted, triggering incident was Y-N fault

in the line at a distance of 21KM from Asupaka end. At both

the ends, fault was sensed in zone-1. At Asupaka end, A/R

operated line tripped on persistent fault in Zone-1. At Lower

Sileru end, A/R operated and line tripped on operation of zone-

1 with a delay of 400ms after reclose. Delayed fault clearance

at Lower Sileru end needs review.

APGENCO to troubleshoot to identify the reason for improper tripping of the line during

the incidence, and to follow standard operating practices while charging of a line after the

line trips on fault

APGENCO Yet to be informed Pending

Andhra Pradesh

Annexure-C

Page 11 of 52

84/II/9Tripping of 220kV Bus 2 and

connected elements at 220kV

Gazuawaka Substation.

17-04-2019 at 5:40 hr.

Triggering incident was Y-phase to earth fault in 220kV

Gazuwaka Bus-2. This resulted in tripping of 220 kV

elements and 400/220 kV ICT-2

1. APTRANSCO to submit a detailed report regarding the subject tripping at 220 kV

Gazuawaka Substation along with the remedial measures taken.

2. For all lines emanating from Gazuwaka SS, RTV coating shall be taken up.

APTRANSCO

APTRANSCO mail dated 30.07.2019:

1. The report submitted vide mail dated 29.07.2019 -- Completed

2. Pending

APTRANSCO mail dated 03.10.2019 and 29.10.2019:

2).Tenders is under process for RTV coating of all the lines emanating from Vizag Switching Station.(VSS) -- Pending

Pending

86/I/3Complete outage of 220

kV/132kV Paravada SS of

APTRANSCO

08-08-2019 at 11:34

hrs

Triggering incident was failure of Y-ph LA of 220 kV

Paravada- VSS (Vizag Switching Station) line at Paravada

end.

1. APTRANSCO to submit equipment failure report to CEA,in respect of the failed

Lightning arrester, and to ensure healthiness of Lightning arresters in other phases.

2. APTRANSCO shall also regularly perform third harmonic current measurement (THRC)

and measurement of LA stack temperature to monitor healthiness of LA’s.

APTRANSCO


1. Equipment failure report to CEA in respect of the failed Lightning arrester will be sent soon, and healthiness of Lightning arresters

in other phases are already checked on 08-08-2019.

2. Third harmonic current measurement (THRC) kit not available with APTRANSCO. Measurement of LA stack temperature to

monitor healthiness of all LA’s is done every month along with other equipment and this month testing is scheduled on 02-11-2019 . -

-Completed

Pending

86/II/19

Tripping of 400 kV Simhadiri-

Kalpakka line-1,2&3; 400

kVKalpakka-Asupaka line-1

&400 kVKalpakka-Gazuwaka

line-2

5-08-2019 at 13:37 hr.Triggering incident was failure of R-phase LA in 400 kV

Kalpakka-Asupaka line.

APTRANSCO to implement line differential protection for 400 kV Simhadri- Kalpakka line

immediately and required OFC/OPGW may be arranged within a weekAPTRANSCO


The line differential protection was enabled in 400 kV kalapaka PGCIL(Gajuwaka) I & II feeders, 400 kV kalapaka HNPCL I & II

feeders. LC was programmed on 15.10.2019, 17.10.2019 and 18.10.2019 for testing and enabling the differential feature in 400 kV

Kalapaka Simhadri-2,3, &, 4 feeders. clearance for testing was not accorded from M/s NTPC. As and when the clearance is

accorded from M/s NTPC the differential feature will be enabled in 400 kv kalapaka Simhadri-2,3&4.

87/1/2

Complete Outage of 220 kV

Vizag Switching Station and

220 kV Parawada SS of

APTRANSCO

28/08/2019

at 15:3

a. Bus-1 and Bus-2 Bus Bar Protection operated due to

snapping of R-phase dropper jumper at 220 kV VSS r

esulting in the tripping of all the connected elements. b. 400

kV/220 kV ICT#1 and 2 at Gazuwaka also got tripped during

this event.

c.220 kV Paravada SS was radially fed from 220 kV VSS

during antecedent conditions.

1. APTRANSCO to investigate whether ageing or tension led to failure of R-Phase dropper

from Jack bus to bridge which led to complete outage of 220 kV VSS and Parawada.

2. Healthiness of other jumpers at 220 kV VSS shall be ensured and a report shall be

furnished to SRPC. APTRANSCO to submit Thermovision scanning reports of 220 kV

VSS during past 6 months and ensure time sync at 220 kV VSS.

APTRANSCO


1. Pending

2. Thermovision scanning report furnsihed on 25.02.2021 - CompletedPending

87/III/3Tripping of 400 kV

Maheshwaram-Narnoor line22-08-2019 at 4:00 hr.

B-phase to earth fault occurred in line. Auto-reclose was

successful at Mahshwaram and A/R not operated at Narnoor

1. APTRANSCO to submit a report after checking A/R operation.

2. APTRANSCO to configure OVR start in EL.APTRANSCO Yet to be informed Pending

88/1/4Complete Loss of Supply at

400/220kV Narnoor station

29-11-2019 at 20:08

Hr.

Triggering incident was fault in 400kV Narnoor - Srisailam

line. LBB of Bus-1 operated and all elements connected to

Bus-1 tripped. Since there was no other infeed to Narnoor

station, there was complete loss of supply at 400/220kV

Narnoor station. In the antecedent, Main breaker of 400kV

Narnoor-Srisailam was in lockout condition and 220kV

Narnoor -Somyzulpalli line-1 &2 was in idle charged

condition.

APTRANSCO to ensure proper segregation of loads, generators and ICTs on both buses in

case of one and half breaker scheme while planning of substationsAPTRANSCO Yet to be informed Pending

88/II/19Tripping of 400kV Kalpakka

Vemagiri line-1

28-10-2019 at 09:51

Hr.

Triggering incident was R-N in the line. Fault was sensed in

Zone-1 at both the ends. At both the ends A/R operated and

line got tripped due to persistent fault. But at Kalpaka end,

after A/R operation even though the fault was sensed in zone-

1 there was delayed opening of all 3 ph breakers for around

250ms.

APTRANSCO to submit a report, after consultation with OEM, regarding the delay in

tripping of 400kV Kalpakka Vemagiri line-,1 inspite of the fault being detected in Zone-1.APTRANSCO Yet to be informed Pending

88/II/24Tripping of 400/220kV ICT-1,

ICT-2 and ICT-3 at Vemagiri

18-11-2019 at 21:54

Hr.

Triggering incident was ICT-2, B-phase LA flashover. ICT -2

tripped on differential protection and ICT-1 and ICT-3 tripped

on over current protection.

APTRANSCO to devise SPS scheme, designed to trip some loads in the event of tripping

of any of the 400/ 220kV ICT’s at Vemagiri, to prevent cascaded tripping of all ICT’s due

to overload in the event of outage of one ICT.

ii. Also APTRANSCO to configure standalone EL with contacts wired from all static relays.

APTRANSCO Yet to be informed Pending

89/1/3Complete outage of 220 kV

Bommuru SS of APTRANSCO

01-01-2020 at 11:40

Hr.

• Bus bar protection operated resulting in complete outage of

220 kV Bommuru SS.

i. APTRANSCO to enable auto-reclosure in all lines emanating from 220 kv Bommuru SS.

ii. APTRANSCO to ensure time synchronization of relays with GPS at 220 kV Bommuru

SS and 220 kV Vemagiri SS.APTRANSCO Yet to be informed Pending

89/II/17Tripping of 400 kV Vemagiri –

Sattenapally line of

APTRANSCO

10-01-2020 at 13:59

Hr.

• As reported, bus bar protection of 400 kV Bus-2 operated at

Vemagiri resulting in tripping of 400 kV Vemagiri –

Sattenapalli line.

APTRANSCO to expedite the process of replacing Static BBP at 400kV Vemagiri SS with

numerical BBP, to prevent mal-operations of BBP at Vemagiri SS.APTRANSCO

KSEBL Mail dated 05.02.2022

The work is in progress along with the replacement of 220kv Control Panels. Scheduled to be completed by 20.02.2022.Pending

90/III/2Tripping of 400KV Vemagiri

(AP) - Simhadri-II

10-01-2020 at 13:59

Hr.

Triggering incident was R-N fault in the line. As per the report

submitted at Vemagiri end, it was mentioned that A/r operated

and line tripped due to persistent fault. But from DR, it was

observed that immediately after the opening of R pole, Y and

B pole also got opened. As per the report submitted at

Simhadri end, it was mentioned that A/r not operated due to

receipt of DT from Vemagiri end. Non operation of A/r and

sending of DT at Vemagiri end needs review.

APTRANSCO to sort out time sync issue in 400KV Vemagiri (AP) - Simhadri- line-2. APTRANSCO Yet to be informed Pending

90/III/3Tripping of 400kV Hinduja -

KV Kota Line-2

10-01-2020 at 13:59

Hr.

Triggering incident was RN fault in the line. A/r not operated

at KV Kota end due to carrier fail. At Hinduja end, A/r

operated and line tripped due to persistent fault. Non

operation of A/r at KV Kota end needs review.

APTRANSCO to check the reason for non-operation of A/R and time sync issue at KV

Kota SS and furnish a report after testing.APTRANSCO Yet to be informed Pending

Annexure-C

Page 12 of 52

90/III/15Tripping of 400kV Hinduja KV

Kota line-1

06-11-2019 at

11:33:00 Hr.

Triggering incident was R phase to Earth fault in the line.

Fault was sensed in Zone-1 at both the ends. A/r operated

successfully at HNPCL end and line was holding. At KV Kota

end, A/r not operated and the same needs review.

• APTRANSCO to check the reason for non-operation of A/R at KV Kota SS and furnish a

report after testing. APTRANSCO Yet to be informed Pending

91/II/9Tripping of 400kV Vemagiri-

Sattenapally line

28-04-2020 at

16:42Hrs


• A/r operated at both the ends and line tripped due to

persistent fault.

• At Vemagiri end, R and Y pole tie breaker didn't open

immediately after A/r operation even though the fault was

persistent.

• Suspected opening of R and Y pole of tie breaker on PD

operation.

APTRANSCO to pursue rectification of the problem of Tie CB at Vemagiri for the subject

line, in consultation with OEM.APTRANSCO Yet to be informed Pending

91/II16Complete outage of 220kV

side of 400/220kV Vemagiri

station of APTRANSCO

14-05-2020 at

00:40Hrs

• As reported control cables caught fire at 220kV Vemagiri

switchyard.

• Bus bar protection of 220kV Bus-1 and Bus-2 operated

resulting in tripping of all connected elements.

• 400/220kV ICT-1,2 and 3 also tripped.

i. APTRANSCO to trigger DR and EL during BBP operation at 400/ 220kV Vemagiri SS.

ii. APTRANSCO to follow relevant standards, Regulations and guidelines to protect cable

trenches and to avoid cable damages due to fire.APTRANSCO Yet to be informed Pending

91/II/17Tripping of 220kV Bus-1 at

400/220kV Vemagiri station of

APTRANSCO

15-05-2020 at

18:07Hrs

• Triggering incident was B-phase insulator disc flashover of

220kV Vemagiri - Bommuru line 2.

• Bus bar protection of 220kV Bus-1 operated resulting in

tripping of all elements connected to Bus-1.

i. APTRANSCO to perform stability check of BBP relays at Vemagiri SS.

ii. APTRANSCO to trigger DR and EL during BBP operation at 400/ 220kV Vemagiri SS. APTRANSCO Yet to be informed Pending-KSPDCL

91/III/10

Tripping of 400kV

Narnoor –

Srisailam LB line

22-04-2020

at 12:51Hrs

• Triggering incident was R-N fault in the line. Line tripped on

Zone-1 distance protection. AR attempted at Narnoor end and

AR not attempted at Srisailam end.

APTRANSCO to disable A/R on the subject line at Narnoor end. On all lines emanating

from Srisailam Left Bank, A/R shall be disabled at remote end.APTRANSCO Yet to be informed Pending


400/220kV Vemagiri station

16-06-2020 at 02:20

Hr.

• Triggering incident was Y-ph to ground fault in 220kV

Vemagiri - Bommuru Line-2. As reported, a creeper fell on Y-

Phase bus-2 Isolator dropper of the line.

• Bus bar protection of 220kV Bus-2 operated and all

elements connected to the bus tripped.

APTRANSCO to clear all debris/scraps from switchyard, to practice periodic thermal

scanning and adopt proper substation maintenance to avoid frequent BBP faults at 400/

220kV Vemagiri SS.



400/220kV Vemagiri station

20-06-2020 at 06:22

Hr

• Triggering incident was B-ph to ground fault in 220kV

Vemagiri - Vijjeswaram feeder. As reported, an aluminium

lead fell on B-Phase, Bus-1 isolator dropper connected to

220KV Vijeswaram feeder.

• Bus bar protection of 220kV Bus-1 operated and all

elements connected to the bus tripped

APTRANSCO to clear all debris/scraps from switchyard, to practice periodic thermal

scanning and adopt proper substation maintenance to avoid frequent BBP faults at 400/

220kV Vemagiri SS.


92/II/12Tripping of 400kV Uravakonda-

Talarichevu line-2

24-06-2020 at 15:55

Hr.

• Line tripped only at Talaricheruvu end on operation of 86A

& 86B relays due to wrong configuration in PSL logic during

carrier failure condition.

• It was also reported that there was Channel-1 failure

momentarily for 2-3s.

APTRANSCO to resolve in PSL logic issue at Talarichevu end relay of the line at the

earliest to avoid unwanted tripping of the line to facilitate RE evacuation.APTRANSCO Yet to be informed Pending

92/IV/6Tripping of 400kV Kalpakka -

Gazuwaka line-1 and 2

24-07-2020 at 11:41

Hr.

• Line tripped (only) at Kalpakka end on DT Receipt, due to

suspected maloperation of PLCC.

APTRANSCO to check the PLCC equipment of the line and rectify the problem of PLCC

maloperation.APTRANSCO Yet to be informed Pending

93/I/1Complete outage of 220/132

kV Chittoor station of

APTRANSCO

02-08-2020 at 03:46

Hr.

09-08-2020 at 09:02

Hr.

09-08-2020 at 10:46

Hr.

• Triggering incident was current spike detected in 220

kVKalikiri feeder due to suspected problem in CB interruption

circuit.

• It is reported that current detected was in the range of

14.5kA. This led to the operation of bus bar protection of

220/132 kVChittoor bus and all connected elements at 220

kVChittoor tripped.

• 220 KVChittoor station has single bus configuration. 132

kVChittoor was also affected since it is radially connected.

i. APTRANSCO to implement multiple bus operation (Main and transfer bus or double bus

scheme) at their 220/132kV Chittoor substation.

ii. APTRANSCO to ensure GPS time synchronization of all relays at their 220/ 132 kV

Chittoor SS.

APTRANSCO


i) Double Bus or Main & transfer Bus scheme cannot be implemented at Chittoor SS due to space constraints. - Pending

Ii) The GPS time synchronization is done for all relays at 220KV Chittoor SS - Complied

Pending

97/II/14Tripping of 220 kV Bus-1 of

220/33 kV NP Kunta PS-3 of

APSPCL

24-06-2021, 09:10 hrs.

triggering incident was tripping of 220 kV NP Kunta PS-3

Line 2 due to isolator jumper clamp breakdown. Since this is

the only line connected to Bus-1, this led to de-energisation of

220 kV Bus-1 at 220 /33 kV NP Kunta PS-3.

i) APSPCL, in coordination with PGCIL (SR-I), to take steps to restore communication link

and bring Line Differential Protection (LDP) into service on 220 kV NPKunta PS-3 –

NPKunta PS D/C line.

ii) APSPCL to sort out all issues in downloading DRs & EL’s of the protection relays at

their NP Kunta PS-3 station, and configure them for appropriately for capturing all requisite

protection operations.

APSPCL Yet to be informed Pending

100/I/A/4Complete Outage of 220kV

Gooty _SWS of APTRANSCO

08-01-2022 at

19:46 hrs

As per the report submitted, Y-phase insulator string of

220kV Gooty_SWS Bus-1 got failed and fell on 220kV

Boyareddipalli line R-phase Jumper at 220kV Gooty_SWS

end. Immediately, BBP of 220kV Bus 1 & 2 operated and all

the elements connected to the buses got tripped. This resulted

in complete outage of 220kV Gooty_SWS.

APTRANSCO to sort out the issue of delayed operation of BBP relay at 220kV Gooty

SWS in consultation with OEM and submit a report to SRPC. APTRANSCO Yet to be informed Pending

Annexure-C

Page 13 of 52

100/I/A/6

Complete Outage of 220kV

Gooty_SWS and Multiple

Trippings in 220kV/132kV

Gooty_RS of APTRANSCO

20-01-2022 at

20:12 hrs

As per the report submitted, triggering incident was failure of

B-ph CT of 220kV Gooty_SWS - Gooty_RS line at 220kV

Gooty_RS end. At 200kV/132kV Gooty_RS, 220kV side

BBP operated and all the connected elements got tripped.

132kV Gooty_RS was intact during this event. At 220 kV

Gooty_SWS, Gooty_RS feeder was not tripped and all the

connected source feeders got tripped at remote ends including

400kV/220kV Gooty_PG ICT#1,2, and 3. This resulted in

1. APTRANSCO to configure LBB protection to send DT to remote end at 220kV

Gooty_RS SS.

2. APTRANSCO to attend time-sync issues at their 220kV Gooty RS and 220kV Gooty

SWS.


Annexure-C

Page 14 of 52

88/II/3Tripping of 220kV KTPS-

Nunna

27-09-2019 at 14:41

Hr.

· Line tripped at Nunna end only on operation of Zone-2


· It was further mentioned in the report that there was bus

fault at KTPS end.

• Non operation of protection at KTPS end needs review

TSGENCO to verify the relay DRs and EL corresponding to the event and submit a report

to SRPC regarding the event.TSGENCO

TSGENCO mail dated 16.06.2021:

Frequent tripping of KTP-Nunna feeder happened due to non opertation of Auto REclosure.Auto Reclosure function for 220kV

KTPS-Nunna feeder at KTPS end was enabled and tested successfully on dt.05.07.2021. After commissioning of A/R at 220kV

KTPS-Nunna feeder on 05.07.2021, certain descripencies with regard to Carrier Aided protection was observed and the same was

communicated to the Firm as the Relay is under warranty period. Accordingly, the firm has deputed the service Engineer on

20.09.2021, and resolved the issues of A/R function.Hence, it is requested to drop the point

Pending- Report of

verification of the relay

DRs and EL

corresponding to the

event.


Srisailam Generating Station

(SLB) of TSGENCO

20-08-2020 at 22:25

Hr

• As reported, fire broke out at 400 kVSrisailam LB station of

TSGENCO. All running units at Srisailam LB tripped one

after another.

• All connected lines at Srisailam LB station tripped at remote

end on Zone-2, distance protection and DT also received.

• Oscillations were also observed from 22:24 Hr. to 22:46 Hr.

in Southern Region during the event. Oscillations died out

after tripping of all the running units at Srisailam LB

TSGENCO to submit a detailed report and suggestions of their technical enquiry

committee for information and discussion in the PCSC forum. TSGENCO Yet to be informed Pending

93/V/2Frequent tripping of 220 kV

Chilakallu - Pulichinthala line

August - September

2020

220 kVChilakallu - Pulichinthala line tripped a number of

times during August - September 2020. It was informed in

PCSC-92 that A/R is yet to be put in service at Pulichinthala

end.

TSGENCO to enable A/R at Pulichinthala SS at the earliest and to take care of the

following at Pulichinthala end:

a. Zone pick up to be configured in DR and EL.

b. DR time scale to be increased to atleast 2.5 sec.

c. To ensure time sync of relays.

TSGENCO Yet to be informed Pending


Srisailam Right Bank of

APGENCO

16-Nov-20

20:26 hrs

Triggering incident was failure of CB of U#5 at Srisailam RB.

LBB operated resulting in the tripping of all the elements

connected to Bus-1 at Srisailam RB. There was no generation

at Srisailam LB during antecedent conditions.

TSGENCO to submit a report detailing the following, along with remedial action taken:

i. LBB operation on account of the failure of R-ph limb of CB of Unit-5 and consequent

tripping of all 220 kV Bus-I connected elements

ii. Tripping of 220kV Srisailam RB – Nagarjunasagar_TS line from Nagarjunasagar_TS end

during above incident.


84/II/27Multiple tripping at 220 kV

Ghanapur station

27-05-2019 at 02:04

hr.

Triggering incident was failure of B-phase CT of bus coupler

of Bus-2. Bus bar protection of 220 kV Bus-2 operated

resulting in tripping of all elements connected to Bus-2.

1.TSTRANSCO is recommended to submit Equipment failure report to CEA regarding the

blast CT.

2.TSTRANSCO to inform if any old CTs exist in Ghanapur SS and ensure healthiness of the

same to

TSTRANSCO

TSTRANSCO MAIL DATED30.10.2019:

1. Informed our transmission wing to submit the Equipment failure report to CEA.

2. All the existing old CTs are replaced with new one.

Pending

89/II/8Tripping of Bus-2 at 220 kV

Malyalappali (Ramagundam)

station.

21-12-2019 at 03:10

Hr.

• Triggering incident was B-N fault in 220 kV Malyalapalli-

Ramapur line.

• LBB of Bus-2 operated since B-phase CB of 220 kV

Malyalappali-Ramapur line did not open due of damage in trip

coil

TSTRANSCO to ensure A/R functionality on all lines emanating from 220 kV Malyalapalli

SS and to ensure time synchronization of relays between Rampur and Malyalapalli.TSTRANSCO


Time synchronization is done. PLCC panel erection for Rampur feeder is under progress.

TSTRANSCO Mail dated 10.02.2022:

TSTRANSCO: PLCC panel erection of Rampur feeder is completed on 16-02-2021.

Pending


DICHPALLY - NIRMAL line-

2

22-05-2020 at

07:12Hrs

• Line tripped on operation of overvoltage stage-1 protection

at Dichipally end and DT received at Nirmal end.

• From the Dichipally end DR, R-phase voltage is observed to

be much higher than the other two phase voltages.

TSTRANSCO to check the transient performance of CVTs at Dichipalli SS. TSTRANSCO


Issue with the neutral links provided in the CVT MB for connecting the CVT core neutral earthing suspected. Intimated the MRT

wing to check with the neutral links in the CVT MBs.


TSTRANSCO:

Neutral links are bypassed in the CVT MB and t

here are no maloperation on account of Over Voltage at present.

TSTRANSCO Mail dated 10.02.2022

TSTRANSCO: Transient performance of CVTs are found to be OK. There are no mal operations on account of Over Voltage after

bypassing Neutral links in CVT MBs.

Pending

95/II/7400 kV Bus-1 outage at

400/220 kV Suryapet SS of

TSTRANSCO

20-01-21

20:57 hrs.

Triggering incident was tripping of 400 kV Suryapet - VTPS

lines – 1 & 2 at Suryapet end due to suspected relay mal-

operation. Subsequently 400kV Suryapet - Kethyreddypalli-2,

400kV Suryapet - Malkaram and 400kV Suryapet - KV Kota

end tripped on operation of OV St-1 protection. Due to

tripping of 400kV connected lines at Bus-1 of 400kV

Suryapet SS, there was de-energization of 400kV Bus-1.

TSTRANSCO to rectify DC leakage issues at their 400/ 220 kV Suryapet SS in two months

time.TSTRANSCO

TSTRANSCO Mail dated 10.02.2022

TSTRANSCO: DC earth leakages at 400kV Suryapet are rectified on 27-11-2021.Pending

Telangana

Annexure-C

Page 15 of 52

95/III/3Tripping of 220 kV Asupaka –

Lower Sileru line-1

05-Jan-2021 11:52 hrs.

27-Feb-2021 13:24

hrs.

28-Feb-2021 11:23

hrs.

Triggering incident was R-E fault in the line. At ASUPAKA

end fault was sensed in Zone-1 with a fault current of 2.7kA

and at a distance of 34km and A/R did not operate. However,

the other 2 poles tripped after 1.5 sec resulting in 3 ph

tripping of the line. At L SILERU end fault was sensed in

Zone-2 carrier aided trip with a fault current of 1.8kA and

A/R got operated. The A/R was successful but subsequently

the line tripped on earth fault without any significant fault

current.

Triggering incident was R-E fault in the line. At Asupaka end,

Zone-1 protection operated and line got tripped. At Lower

Sileru end, carrier aided zone-2 protection operated and line

got tripped. A/R did not operate at both the ends.

Triggering incident was Y-E fault in the line. At Asupaka end,

fault was sensed in zone-1. A/R operated and line tripped on

persistent fault. At Lower Sileru end, Zone-1 protection

operated and line got tripped. A/R did not operate

TSTRANSCO to rectify the issue of unsuccessful A/R at Asupka end for the line in two

weeks time.TSTRANSCO


TSTRANSCO: Rectified the issue of unsuccessful A/R at Asupaka SS by the Service Engineer on 04-10-2021.

Pending

95/III/6Tripping of 220 kV Chillakallu

– Pulichintala line13-Jan-2021 15:04 hrs.

Triggering incident was R-E fault in the line at a distance of

25.95 km from chillakallu end. At Chillakallu end, fault was

sensed in zone-1. A/R operated and line was holding. At

Pulichintala end, Fault was sensed in zone-1, A/R did not

operate and line got tripped.

TSGENCO to ensure enabling of A/R on all 220 kV lines at their Pulichinthala station in two

weeks time. DR time duration shall be maintained as 2 sec and all distance protection zones

to be configured in DR.


95/IV/1Tripping of 400 kV Srisailam -

Dindi -122-Jan-2021 15:58 hrs.

Line tripped only at Srisailam LB end on receiving DT from

remote end due to suspected mal-operation of PLCC

i. TSTRANSCO to check & remove DC earth leakages at their 400/ 220 kV Dindi SS.

ii. TSTRANSCO, in coordination with TSGENCO, to carry out PLCC end-to-end testing for

the subject line to ensure healthiness of the same.

TSTRANSCO

TSGENCO mail dated 09.12.2021

ii. End to end PLCC test was carried out on 03.03.2021 and ensured all communication signal found normal.

TSTRANSCO Mail dated 10.02.2022:

TSTRANSCO:

i. There are no DC earth leakages at Dindi SS.

ii. End to end PLCC testing was carried out on 03-.03.2021.

Pending

97/I/7Complete outage of 400/220

kV Mamidipally SS of

TSTRANSCO

24-06-2021, 19:25 hrs.

Triggering incident was fire in HV side B-ph LA stack of

400/220kV ICT-1. Because of this, all the ICTs along with

400kV, 220kV feeders were hand-tripped as per the SLDC

instructions. This resulted in complete outage of 400/220 kV

Mamidipally SS.

TSTRANSCO to submit a detailed Action Taken Report w.r.t. the Fire Incident at their 400/

220 kV Mamidipalli SS including the measures proposed at other (old) TSTRANSCO

substations facing similar issues.

TSTRANSCO Yet to be informed Pending

Annexure-C

Page 16 of 52

Karnat

aka

Mail received on 21-10-2015:

1) Anti-pumping contactors of all the nine 220KV Lines are in circuit and tested periodically during AOH works of lines along with

other protections.

2) Completed.

3) Possibility to use both the 220kV buses as main bus under normal operation is under review.

Mail recieved on 23-11-2015:

1) Completed

3) Two bus operation for 220kV buses : In place of existing CT switching relays, High speed manual heavy duty change over switch

of sufficient current capacity will be retrofitted to all feeders at 220kV station and same will be operated manually during changeover

of feeder by one bus to the other and this arrangement may facilitate to put both buses in service. Time required for this retrofit is

around 90days . However, this work will be taken up only after retrofitting of electromagnetic relays with numerical relays for Main-

2 protection of all 220kV lines, for which work is in progress.

Status received vide mail dated 10-07-2017:

1) --- Completed.

2) --- Completed.

3) Two Bus operation for 220kV bus is being carried out whenever required. However scheme for tripping of one bus during

LBB/fault and maintaining the other bus intact by tripping B/C breaker will be taken up in R&M works. --- Pending

KPCL07-06-2015 at 01:35

hrs

1. KPCL to check the operation of anti-pumping relay on 220 kV side and keep it in healthy

condition.

2. KPCL to provide manual reset to the 220 kV side master trip relay.

3. KPCL to use both the 220 kV buses as main buses under normal operation, and should go

for single bus operation only during emergencies.

Sl No. 1 & 2 Completed

Sl No. 3: Pending46/II/21

Trippings at 220kV Raichur

TPS

Annexure-C

Page 17 of 52

Status received vide KPCL mail dated 14.12.2017:

3) DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is placed for funds from

PSDF. After the approval of the DPR, the work is proposed to be taken up.


3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is

placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested for is 2 yrs.


3) Work proposed to be taken up under PSDF. Approval from Nodal agency is awaited. However, arrangements have been made to

issue NIT.


KPCL informed that Tender would be floated in 1 month and work would be completed in 2 years.


Tender would be floated in 1 month and work would be completed in 2 years.


Arrangements have been made to issue NIT and Tender for the work proposed to be floated during May- 2019.


NIT will be issued during May- 2019.


1. & 2. Completed

3) Preparation of technical specification is in progress. NIT will be issued during July- 2019.


KPCL informed that timeline for completion of work is December 2019.


1. & 2. Completed

3) Preparation of technical specification is in progress. NIT will be issued during July- 2019. timeline for completion of work is

December 2019.

KPCL mail dated 30.10.2019 and 17.12.2019 and 11.02.2020:

1. & 2. Completed

3) NIT issued during Aug- 2019. Timeline for completion of work is December 2020.


1) & 2) Completed

3) NIT issued during Aug- 2019. Tender evaluation is completed. Approval from Nodal Agency for PSDF funds is received on

31.03.2021. Obtained HO approval for placing LOA on L1 bidder.LOA placed on M/s G E T&D on dated 11.06.2021 and work is in

progress.


1) & 2) Completed

3) NIT Issued during Aug- 2019. Tender evaluation is completed. Approval from Nodal Agency for PSDF funds has been received

on 31.03.2021. Obtained HO approval for placing LOA on L1 bidder.LOA placed on M/s G E T&D on dated 11.06.2021 and work


1. (ii) Hot line water washing stopped and off line water washing is carried out whenever the 400 KV Unit or line is under tripped

condition / Shutdown condition. --- Completed

1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same is under observation. Till today in order and

good condition. For remaining breakers, since it is big order, approval for the same is under process. --- Pending

2. Static / Electromechanical relays are existing in all 1 to 7 units. Breaker flash over protection feature will be enabled (if available)

in the numerical relays which will be retrofitted in phased manner during R&M works.


1.(i) --- Pending

1. (ii) Hot line water washing stopped and off line water washing is carried out whenever the 400 KV Unit or line is under tripped

condition / Shutdown condition. --- Completed

1. (iii) Silicon coating for Unit#8 main & tie breakers carried out in Sep'16 and same is under observation. Till today in order and

good condition. For remaining breakers, since it is big order, approval for the same is under process --- Pending

2. Static / Electromechanical relays are existing in all 1 to 7 units. Breaker flash over protection feature will be enabled (if available)

in the numerical relays which will be retrofitted in phased manner during R&M works --- Pending

13-04-2016 at 21:12

hrs

Tripping of 400kV Raichur

TPS

Bus-2

KPCL07-06-2015 at 01:35

hrs

1. KPCL to check the operation of anti-pumping relay on 220 kV side and keep it in healthy

condition.

2. KPCL to provide manual reset to the 220 kV side master trip relay.

3. KPCL to use both the 220 kV buses as main buses under normal operation, and should go

for single bus operation only during emergencies.

KPCL

1.KPCL to undertake the following remedial measures to avoid breaker flashovers:

(i) Replacing all porcelain insulators with composite insulators

(ii) Carrying out hot-line water washing of all insulators on regular basis.

(iii) Applying Room Temperature Vulcanizing (RTV) Silicone high voltage insulator

coatings to all bus-connected ceramic insulators of equipment like CT, PT, CB, Isolators etc.

2.KPCL to take steps to provide dedicated breaker flashover protection to all breakers at

Raichur TPS at the earliest.

54/II/9

Sl No. 1 & 2 Completed

Sl No. 3: Pending

Pending

46/II/21Trippings at 220kV Raichur

TPS

Y-ph Pole of Tie-breaker of Unit-4 at RTPS failed. Unit-4 got

tripped on operation of Generator Differential, Reverse power

& LBB protection. Operation of LBB protection led to

tripping of BUS-2 at RTPS

Annexure-C

Page 18 of 52


1 (iii) As upgradation of 400kV switchyard equip's to be taken under PSDF funds, Silicon rubber coating for breakers is deffered till

then. --- Pending

2. Replacement by Num relay for Units - 5,6 & 7 completed in the month of Oct-2017. Main-I is Seimens make and Main-II is ABB

make. --- Pending


2. Replacement of Numerical relays for Units-5, 6 & 7 have been completed. Referred to OEM for providing the Breaker flashover

protection for all the breakers.


2. Reply is awaited from OEM of Numerical relays for providing Breaker Flashover protection for all the breakers --- Pending


1. KPCL assured that porcelain insulator replacement will be taken care in tender floated for RTPS Busbar modification --- Pending


1) i) Being discussed with other utilitis.

2) Reply is awaiting from OEM to implement the Breaker flash over protection in the Numerical relays referring to the protection

implemented in other 400KV station.


1) (i) & (iii)- Arrangements have been made to issue NIT and Tender for the work proposed to be floated during May- 2019.

2) Reply is awaiting from OEM to implement the Breaker flash over protection in the Numerical relays in 400KV station. & Being

discussed with other utilities.

It is requested to furnish Necessary logic and settings to implement the breaker flashover protection


1) (i) & (iii)- NIT floated on 01.03.2019

2) Reply is awaiting from OEM to implement the Breaker flash over protection in the Numerical relays in 400KV station. & Being

discussed with other utilities.

It is requested that SRPC may suggest/furnish reference of necessary logic and settings to implement the breaker flashover

protection.

KPCL mail dated 25.06.2019:Review meeting on 27.06.2019:

SRPC informed that referenc of necessary logic and settings to implement the breaker flashover protection will be shared soon.


1) (i) & (iii)- NIT floated on 01.03.2019. Cover-I opened. Technical evaluation is in progress. Approval from Nodal Agency for

PSDF funds is awaited.

2) As confirmed during 84th PCSC meeting, SRPC may suggest/furnish referenc of necessary logic and settings to implement the

breaker flashover protection. reply in this regard is awaited.

KPCL mail dated 30.10.2019 and 17.12.2019 and 11.02.2020 & 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 &

22.01.2021:

1) (i) & (iii)- NIT floated on 01.03.2019. Tender evaluation is completed. Approval from Nodal Agency for PSDF funds is awaited


2) As confirmed during 84th PCSC meeting, SRPC may suggest/furnish referenc of necessary logic and settings to implement the



1) (i) & (iii)- NIT floated on 01.03.2019. Tender evaluation is completed. Approval from Nodal Agency for PSDF funds is recieved

on 31.03.2021. Awaiting HO approval for placing LOA on L1 Bidder.

2) As confirmed during 84th PCSC meeting, SRPC may suggest/furnish reference of necessary logic and settings to implement the




on 31.03.2021. Obtained HO approval and placed LOA on L1 Bidder on dated 11.06.2021, work is in progress.

2) As confirmed during 84th PCSC meeting, SRPC may suggest/furnish reference of necessary logic and settings to implement the

breaker flashover protection,early solution in the matter requested.



on 31.03.2021. Obtained HO approval and placed LOA on L1 Bidder on dated 11.06.2021, work is in progress.

13-04-2016 at 21:12

hrs

Tripping of 400kV Raichur

TPS

Bus-2

Timeline?

KPCL

1.KPCL to undertake the following remedial measures to avoid breaker flashovers:

(i) Replacing all porcelain insulators with composite insulators

(ii) Carrying out hot-line water washing of all insulators on regular basis.

(iii) Applying Room Temperature Vulcanizing (RTV) Silicone high voltage insulator

coatings to all bus-connected ceramic insulators of equipment like CT, PT, CB, Isolators etc.

2.KPCL to take steps to provide dedicated breaker flashover protection to all breakers at

Raichur TPS at the earliest.

54/II/9 Pending

Y-ph Pole of Tie-breaker of Unit-4 at RTPS failed. Unit-4 got

tripped on operation of Generator Differential, Reverse power

& LBB protection. Operation of LBB protection led to

tripping of BUS-2 at RTPS

Annexure-C

Page 19 of 52

Status received vide KPCL mail dated 10.07.2017 & 14.12.2017:

Two Bus operation for 220kV bus is being carried out whenever required. However scheme for tripping of one bus during LBB/fault

and maintaining the other bus intact by tripping B/C breaker will be taken up in R&M works.


3) KPCL informed that DPR for implementation of Two Bus operation for 220kV bus system has been prepared and proposal is

placed for funds from PSDF. After the approval of the DPR, the work is proposed to be taken up. Time frame requested is 2 yrs.

KPCL mail dated 20.12.2018 & 23.01.2019:

Work proposed to be taken up under PSDF. Approval from Nodal agency is awaited. However, arrangements have been made to

issue NIT.


NIT will be issued during May- 2019.


Preparation of technical specification is in progress.

NIT will be issued during June/July- 2019.


KPCL informed that timeline for completion of work is December 2019.


NIT issued during Aug- 2019. Tender evaluation completed.

Approval from Nodal Agency NLDC for PSDF funds received on 31.03.2021 .

Obtained HO approval and placed LOA dated 09.06.2021 on L1 bidder i.e. M/s GE T & D and work is in progress.The scheduled

date of completion is 58Weeks from the date of LOA i.e. 31.07.2022.

KPCL mail dated 16.07.2019 & 30.10.2019:

NIT will be issued during July- 2019. Time line for completion of work is Dec-2020.

KPCL mail dated 17.12.2019 and 11.02.2020 :

NIT issued during Aug-2019.

Time line for completion of work is Dec-2020.

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:

NIT issued during Aug- 2019. Tender evaluation is completed. Awaiting approval from PSDF for placing PO on L1 agency.


NIT issued during Aug- 2019. Tender evaluation completed. Approval from Nodal Agency NLDC for PSDF funds received on

31.03.2021 . Awaiting HO approval for placing LOA on L1 bidder.



Approval from Nodal Agency NLDC for PSDF funds received on 31.03.2021 . Obtained HO approval

and placed LOA dated 09.06.2021 on L1 bidder i.e. M/s G E T & D and work is in progress.The scheduled date of completion is

58Weeks from the date of LOA i.e. 31.07.2022.

KPCL Mail dated 14.02.2022;


Approval from Nodal Agency NLDC for PSDF funds received on 31.03.2021 .

Obtained HO approval and placed LOA on L1 Bidder on dated 11.06.2021, Engineering work & supply of equipments is in progress.

Work will be completed by Dec-2022.

KPCL

Timeline?

Tripping of Units at 220 kV

Raichur TPS 54/II/13 Pending

In view of the availability of two buses along with healthy bus-coupler at 220 kV RTPS,

KPCL is recommended to put in service the double-bus operation at 220 kV RTPS by

suitably distributing loads within 15 days.

15-04-2016 at 15:36

hrs

During testing of retrofitted distance protection in 400kV

Raichur-2 feeder, LBB protection trip DC got extended to

Bus trip. This resulted in tripping of 220kV bus at RTPS and

all connected 220 kV elements. Unit-4 which is connected to

400 kV Bus got tripped due to tripping of Station Utility

Transformer that is connected 220 kV bus

Annexure-C

Page 20 of 52


1. All logics checked and found normal. LBB timing checked and found 200msec as per KPTCL MRT recommendation. -

Completed

2. Work Under Progress ---- Pending

3. New GPS System commissioned along with new numerical and synchronised with GPS system - Complied

4. Work Under Progress ---- Pending

Status received vide mail dated 14.12.2017:

1),3),4) Completed

2. Auto Start of DG set is taken up --- Pending


2. KPCL informed that for AMF of DG, Scheme prepared & material procurement under process. The AMF scheme will be

implemented in January 2018. --- Pending

3. The GPS system commissioned on Nov 2016 & all the numarical relay time synchronised with GPS ---- Completed


AMF panel procurement under progress.

KPCL mail dated 20.1.2.2018:

2. AMF scheme implementation is included in the work ''Replacement common auxiliary panel with latest technology SCADA

compatibility system'' . Availing administration approval is under progress


KPCL informed that Tender for the work would be floated by January 2019 and work would be completed in 1 year.


1) Completed.

2) Tender for the work would be floated by February 2019 and work would be completed in 1 year....Pending

3) Completed.

4) Tender for the work would be floated by Feb, 2019, and work would be completed in 1 year....Pending


2) Tender for the work proposed to be floated during May- 2019 after model code of conduct and work would be completed in 1

year .

4) Tender for the work proposed to be floated during May- 2019 after model code of conduct and and work would be completed in

1 year.


Tender will be floated during 3rd week of May- 2019.


1 & 3) Completed.

2 & 4) Tender published on 21.06.2019.


.1 & 3) Completed.

4) Tender published on 21.06.2019 and time line in June 2020.

2. tender has to be issued. Timeline requested upto December 2020.

KPCL mail dated 16.07.2019 :

1 & 3) Completed.

2 ) NIT will be issued during Aug-2019.

4) Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.

KPCL mail dated 30.10.2019 and 17.12.2019:

1 & 3) Completed.

2 ) NIT issued during Sept-2019.

4) Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.

58/I/3

(GD)

LBB of 220kV Kodasalli breaker at Kadra end got operated

which resulted in tripping of Bus at Kadra and in turn led to

tripping of all elements

06-09-2016

at 14:40 hrsComplete outage of 220 kV

Kadra power station of KPCL

1) KPCL to check settings of LBB protection in all relays from which it was implemented,

and ensure that their configuration, logic, and timing are in order at their 220 kV Kadra PH.

2) KPCL to furnish details regarding the existing LT auxiliary supply arrangement at their

220 kV Kadra PH, and take steps to provide a suitable Auto-Main-Fail (AMF) panel for DG

set to effect its auto-starting in case of failure of LT supply.

3) KPCL to ensure time-sync of all relays (DR’s & EL’s) with GPS at their 220 kV Kadra

PH.

4) KPCL to provide stand-alone Event Logger at their 220 kV Nagjheri PH.

PendingKPCL

Annexure-C

Page 21 of 52


1 & 3) Completed.

2 ) NIT issued during Sept-2019. Tender evaluation is inprogress.

4) As per the directions of TESG of NLDC i..e. Numerical relays are being provided for all Units and Lines, the proposal of

providing Disturbance recorder is excluded from DPR submitted for availing funds from PSDF - Issue may be dropped. --- Dropped

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:

1 & 3) Completed.

2 ) NIT issued during Sept-2019 and resulted in receipt of single qualified bidder in Cover-1. Hence, tender refloated for Call-2 on

April 2020. Evaluation is under progress

4) Dropped.


1 & 3) Completed.

2 ) Work order placed on L1 agency & Engineering work is in progress.

4) Dropped.


1 & 3) Completed.

2 ) Work order placed on L1 agency & Engineering work is in progress.

4) Dropped.


1 & 3) Completed.

2 ) Exsiting breaker ACB is not compatiable for AMF opeation. Hence, LOA is placed & engineering work is in progres for

upgradation of LTAC breakers. After completion of upgradation of LTAC breakers, implementation of AMF will be taken up at the

earliest.

4) Dropped.


Numerical Generator protection relay replacement proposed to be taken up alongwith SCADA work.


Will be taken up along with SCADA work. NIT to be issued on Jan-2019


KPCL informed that Tender for the work would be floated by March, 2019, and work would be completed in 1 year.


Tender for the work would be floated by February-2019 and work would be completed in 1 year.


Tender for the work proposed to be floated during May- 2019 after model code of conduct and work would be completed in 1 year


Tender will be floated during 3rd week of May- 2019.


Tender published on 21.06.2019.


Tender published on 21.06.2019 and time line in June 2020.

KPTCL Mail datred 14.12.2021

Preparation of estimate is completed & obtaining of administrative approval is in progress.


Tender published on 21.06.2019. Time line for completion of Work is Dec-2020.


Tender published on 21.06.2019. No bids received for the tender. Hence, it is proposed to refloat fresh tender with revised PQR and

scope of work. Avaialing approval in this regard is in progress.

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:

Preparation of estimate and technical specification is in progress..







KPCL Mail dated 14.02.2022;


58/I/3

(GD)

KPCLKPCL to take steps to replace the existing static protection relays for Generator Units and

Generating Transformers (GT’s) with suitable Numerical relays at their 220 kV Kadra PH.

06-10-2017 at 22:22

hrs

LBB of 220kV Kodasalli breaker at Kadra end got operated

which resulted in tripping of Bus at Kadra and in turn led to

tripping of all elements

06-09-2016

at 14:40 hrsComplete outage of 220 kV

Kadra power station of KPCL

1) KPCL to check settings of LBB protection in all relays from which it was implemented,

and ensure that their configuration, logic, and timing are in order at their 220 kV Kadra PH.

2) KPCL to furnish details regarding the existing LT auxiliary supply arrangement at their

220 kV Kadra PH, and take steps to provide a suitable Auto-Main-Fail (AMF) panel for DG

set to effect its auto-starting in case of failure of LT supply.

3) KPCL to ensure time-sync of all relays (DR’s & EL’s) with GPS at their 220 kV Kadra

PH.

4) KPCL to provide stand-alone Event Logger at their 220 kV Nagjheri PH.

69/II/8Tripping of 220 kV Kaiga-

Kadra line-1

While de-synchronising of Unit-2, B-phase pole of GCB did

not open and pole descrepancy relay operated. Hence all

220KV lines CB hand tripped.

Pending

Pending

KPCL

Annexure-C

Page 22 of 52

72/I/4


Sedam, Shahapur, Shahabad,

Kapanoor, Humnabad and

Halabarga Stations of KPTCL

01-02-2018

at 17:46 hrs

High resistance fault occurred in 110kV Sedam-Chittapur line

near Sedam end. Line DEF operated and backup OC

protection of 100MVA transformer operated at Sedam end.

But line breaker and transformer HV breaker didn’t open due

to problem in trip circuit. This resulted in cascade tripping of

upstream feeders and power supply was lost to six 220kV

stations of KPTCL.

KPCL to disable GFC protection on all lines emanating from their generating stations. KPCL

Review Meeting on 21.12.2018

KPCL informed that compliance w.r.t. Implementing the recommendation would be furnished soon.


'GFC protection will be disabled in all lines in coordination with M/s.KPTCL

KPCL mail dated 10.05.2019 & 25.06.2019 & 16.07.2019 & 30.10.2019 & 17.12.2019 & 11.02.2020:

Letter addressed to CE, RT, KPTCL dated: 10.04.2019 to disable GFC protection in all 220kV lines . Reply is awaited.

KPCL mail dated 21.05.2020 & 28.09.2020 & 26.11.2020:

Letter dated: 28.04.2020 addressed to CE, RT, KPTCL to disable GFC protection in all 220kV lines . Reply is awaited.

KPCL mail dated 22.01.2021, 26.05.2021, 19.07.2021::

Letter dated: 28.04.2020 addressed to CE, RT, KPTCL to disable GFC protection in all 220kV lines . Reply is awaited.Reminder

letters dated:16.06.2020, 27.08.2020 has been also addressed to CE, RT, KPTCL to disable GFC protection in all 220kV lines. Reply

is awaited.



Reminder letters dated:16.06.2020, 27.08.2020 has been also addressed to CE, RT, KPTCL to disable GFC protection in all 220kV

lines. Reply is awaited.



Reminder letters dated:16.06.2020, 27.08.2020 has been also addressed to CE, RT, KPTCL to disable GFC protection in all 220kV

lines. Reply is awaited.

Pending


Under Implementation.

KPCL mail dated 20.12.2018 & 23.01.2019 & 23.03.2019:

Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service after April-2019


4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Remaining bays will be completed after Concurrence of

LC from LDC

KPCL mail dated 25.06.2019 & 16.07.2019 & 30.10.2019:

4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Remaining bay will be completed after monsoon season i.e

during November -2019

KPCL mail dated 17.12.2019 and 11.02.2020 & 21.05.2020 & 27.07.2020 & 27.07.2020, 28.09.2020 & 26.05.2021::

4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Several times LC is requested for carrying out work for

remaining bay. However, LC is awaited from SLDC.


Isolators of all Lines & Bus coupler bay of North Bus were completed.

Availing approval for procurement of Isolators for remaining bays is in progress.

The placing of work order is in progress for 23Set of remaing isolators. Work will be completed by Dec-2022(monsoon periods are

not considered for erection works) subject to LC availability iof line/unit bays from LDC.

KPCL mail dated 26.11.2020 & 22.01.2021, 19.07.2021:


Availing approval for procurement of Isolators for remaning bays is in progress.



Availing approval for procurement of Isolators for remaining bays is in progress.


not considered for erection works) subject to LC availability iof line/unit bays from LDC.

KPCL15-03-2018 at 22:36

hrs

There was Y-phase to ground fault on 220 kV Varahi -

Shimoga line-2. Consequent to persisting fault in ‘Y’ phase,

the breaker failure protection operated resulting in operation

of 220KV bus bar protection at Varahi, tripping all the

connected lines and Varahi running units.


Varahi power station73/I/5 PendingKPCL to take steps to put double-bus operation into service at their 220 kV Varahi PH.

Annexure-C

Page 23 of 52

KPCL mail dated 20.12.2018 & 23.01.2019:

1. Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service after April-2019 --- Pending

2. ---- Completed.


1) Retrofitting of 220kV Bus Isolators is under progress. Proposed to be in service after April-2019


4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Remaining bays will be completed after Concurrence of

LC from LDC.

KPCL mail dated 25.06.2019 & 16.07.2019 & 30.10.2019:

4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Remaining bay will be completed after monsoon season i.e

during November -2019

KPCL mail dated 17.12.2019 and 11.02.2020 & 21.05.2020 & 27.07.2020 & 28.09.2020:

4 Set of Isolators of VS1, VS2 & VM2 bay of North Bus were cmpleted. Several times LC is requested for carrying out work for

remaining bay. However, LC is awaited from SLDC.

KPCL mail dated 26.11.2020 & 22.01.2021, 19.07.2021:


Availing approval for procurement of Isolators for remaning bays is in progress.



Tender has been floated as Call-2 for replacement of isolators for remaining bays.


87/I/3


Kemar, MSEZ, Puttur&Kavoor

stations of KPTCL

29-09-2019 at 11:31

hrs

a. Single line to ground fault occurred in 220kV Kemar –

Varahi line-2 due to R-phase insulator flashover and the line

tripped on Zone-1 distance protection. Simultaneously, 220kV

Kemar – Varahi line-1 tripped at Kemar end only.

b. 220kV Kemar –Varahi line-3 tripped due to overloading.

This resulted in complete loss of supply at 220kV Kemar

since all the three source feeders tripped.

c. In addition there was complete loss of supply at 220kV

MSEZ, 220kV Kavoor and 220kV Puttur stations since these

stations were radially fed from 220kV Kemar station.

KPCL to check A/R functionality for all lines emanating from 220 kV Varahi GS and submit

a report regarding the same.KPCL


It will be intimated shortly.


During this fault , AR is temporarily kept OFF conditions, due to the wave trap fall down during AR operation of nearby fault on

VM2 Line earlier.

Meanwhile, firm was requested to submitt offer to implement the AR fucntion as per SRPC recommendations for generating station.

KPCL mail dated 26.11.2020 & 22.01.2021:

The firm was requested to submitt offer to implement the AR fucntion as per SRPC recommendations for generating station.

KPCL mail dated 26.05.2021,19.07.2021:

The firm has requested some more time to submit offer due to internal reasons. Reply is awaited from fim in this regard.


The firm has requested some more time to submit offer due to internal reasons. Reply is awaited from fim in this regard.

M/s CPRI has recommended to construct adidtional earth mat linking to Main earth mat for improving overall earth resistance. After

completion of earth mat works, the work will be taken up for implemenation of AR logic as proposed by SPRC for generating

stations.

Tendering for providing additional earth mat is in progress.

Pending

100/I/A/3


Kadra PH, 220kV Kodasalli

PH of KPCL and

220kV/110kV Karwar SS of

KPTCL

26-Dec-2021 08:56 hrs

During antecedent conditions, 220 kV Kaiga-Kadra and 220

kV Kaiga-Kodsalli were in idle charged condition. As per the

report submitted, Y-phase pole discrepancy relay operated

while de-synchronising Unit-2 at Kodasally. At the same time,

Unit-1 LBB operated and all the elements connected to 220kV

Bus got tripped. This resulted in complete outage of 220kV

Kadra PH, 220kV Kodasalli PH of KPCL. This also resulted

in complete outage of 220kV/110kV Karwar SS due to

incoming supply failure from 220kV Kodsalli PH.

KPCL was requested to change the LBB implementation logic at 220kV Kadra PH and to

trigger LBB operation of CB only if LBB is initiated by a protection trip signal. KPCL Yet to be informed Pending

100/II/4Tripping of 400kV RAICHUR -

BTPS

23-12-2021 at

03:45:00 hrs

As per the report submitted, the triggering incident was RE

fault in the line. A/R is in non-auto mode since both the ends

are connected to generators. The fault was sensed in Zone-1 at

both ends. At Raichur end, line tripped on 3ph Zone-1

distance protection. At BTPS end, as per DR, even after 3

phase trip, after 100ms from the opening of breakers, the fault

was observed and the same needs review.

KPCL to investigate reason for unexpected behavior of protection relays at BTPS end for

the subject line and submit a detailed report including the remedial measures taken in

two weeks time.

KPCL Yet to be informed Pending

Due to suspected mal-operation of 220KV bus bar protection

at Varahi, all the connected lines and Varahi running Units got

tripped. (6 nos 220kV lines and 4 nos Varahi generating

station running Units). This resulted in complete outage of

220kV Varahi UGPH

24-08-2018 at 11:00

hrs

Complete Outage of 220 kV

Varahi UGPH.78/I/1 PendingKPCL

1. KPCL to take steps to put double-bus operation into service at their 220 kV Varahi

UGPH by December, 2018.

2. KPCL to employ correct operational practices like keeping DC fuses of B/C CB intact

during bus changeover works, disabling back-up protections of B/C CB during bus

changeover works & enabling them with proper settings only when it is used as Main-CB of

the grid elements.

Annexure-C

Page 24 of 52


1. In view of operating 220kV Ambewadi SS in split bus mode, action is being taken up by KPTCL. Problem in the 220kV bus

coupler breaker is attended and isolator overhauling work is under progress. Spilt bus operation at Ambewadi will be made possible

at the earliest. --- Pending

2. ICT Protection system at Ambewadi and trippings occured at Supa GS during the instance is checked up and remedial measures

already furnished in this regard.

---- Completed

Mail recieved on 29-07-2015:

1. Action is being taken by KPTCL for operating Ambewadi in split bus mode. Problem in bus coupler breaker is attended.Isolator

overhaulling work is completed.PTs are already provided to 220kV Bus-II. After commissioning of Bus-II PTs, Ambewadi can be

operated in split bus mode. Pending works will be completed within a months time.

KPTCL mail recieved on 23-01-2016:

1. Bus-II PTs yet to be commissioned.Planned to complete before end of April-2016.

KPTCL mail recieved on 25-04-2017 & 22.11.2017:

1. Yet to be attended --- Pending

Pending

GD-1 at 220kV Ambewadi

Station of KPTCL

40/I/1

Triggering incident was B-phase to earth fault in 220kV

Ambewadi- Nagzari line-1. B-pole of breaker did not open at

Ambewadi end. LBB protection not available at Ambewadi

end. All elements tripped on Zone-2 from remote ends.

22-12-2014

at 21:22 hrsKPTCL

1. Till the completion of R&M works for bus bar and LBB protection, KPTCL shall explore

the possibility of having split bus operation at Ambewadi and submit the details of the same

to PCSC forum.

2. KPTCL shall provide the details of the tripping of Supa hydro station connected

downstream from 110 kV bus.

Annexure-C

Page 25 of 52

KPTCL Mail dated 16.12.2017 & Review Meeting dated 19.12.2017:

1. Recommended works at Ambewadi have not been taken up due to various problems faced due to poor response from the turn key

agency M/s ERL. A site meeting is planned during this month to discuss about further plan of action for attending SRPC

recommendations pertaining to the Sub station.

The issue was discussed in the review meeting. Considering the importance of the substation and delay in executing the works, it was

decided to escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion.


1. The outstanding protection issues pertaining to Ambewadi were appraised to the management and proposal for construction of

new GIS SUb stations has been approved by KPTCL management. In view of attending protection audit recommendations pertaining

to Ambewadi SS without linking with new Station proposal, action has been taken to include the works in extended scope of R&U

project awarded to M/s GE T&D India Limited. Addition materials required are yet to be supplied by M/s GE.


1. KPTCL will inform the status on progress of work.


1. BBP provided at Ambewadi SS. - Completed


). Bus Bar and LBB Protection provided at Ambewadi.


Procurement of Bus bar and LBB protection is in the final tendering stage. 2. Action is being taken to restore the carrier protection

for 220kV Sedam-Tandoor line. AR will be enabled.


1. Procurement of Bus bar and LBB protection is in the final tendering stage.

2. Action is being taken to restore the carrier protection for 220kV Sedam-Tandoor line. AR will be enabled after restoration of

PLCC.

KPTCL mail received on 23-01-2016:

1. Bus bar protection panels pocured and erected at Sedam. Wiring , testing ,commissioning is being taken up.Planned to complete

by April 2016.


PLCC.

KPTCL Mail recieved dated 22-11-2017:

1 & 2). Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave trap to be commisioned in Tandoor line

and PLCC to be restored.Once PLCC is restored AR will be enabled. The Wave traps required are supplied under R&U project and

the same is to be commisioned at Sedam end for restoration of PLCC.


1 & 2) Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been

supplied by the Agency. The work will be taken up on top priority.


KPTCL informed that the works relating to put A/R in service are going on at their Sedam SS, and assured that it would be put into

service by February, 2018.


1). Bus Bar Protection Work is under progress. Work will be completed in 2 months.

---- Pending

2). ---A/R was enabled from Sedam end on 03.11.2018 ----Completed.


1. Timeline - September 2019

2. Completed


1. Bus Bar and LBB Protection has been Commissioned at Sedam SS .


1. The work is under progress, expected to be put in to service before end of February 2020

2. AR was implemented. But due to problem with single phase trip relays the same was disabled. Now the same has been attended

and expected to be put in to service before end of February 2020

1. Status?

Pending

R-Phase to ground fault occurred on 220kV Sedam-Shahpur

line. Fault not cleared from Sedam end due to stuck-breaker

condition. While the Sedam- Sahapur line tripped from

Shahapur end in Zone-1, the other 220 kv lines from Sedam

tripped at remote ends in Zone-2. This caused complete

outage of 220kV Sedam substation.

GD-1 at 220kV Ambewadi

Station of KPTCL

40/I/1

41/I/4

Triggering incident was B-phase to earth fault in 220kV

Ambewadi- Nagzari line-1. B-pole of breaker did not open at

Ambewadi end. LBB protection not available at Ambewadi

end. All elements tripped on Zone-2 from remote ends.

Complete outage at 220kV

Sedam Substation of KPTCL

(GD-1)

27-01-2015 at 8.00 hrs

22-12-2014

at 21:22 hrs

PendingKPTCL

KPTCL

1. KPTCL to provide Bus bar and LBB protections for 220 kV bus at Sedam S/s.

2. KPTCL to implement A/R feature on 220 kV Sedam-Tandur inter-state line.



to PCSC forum.

2. KPTCL shall provide the details of the tripping of Supa hydro station connected

downstream from 110 kV bus.

Annexure-C

Page 26 of 52


1. Bus Bar protection will be provded under R&U.

2. A/R yet to be enabled.




PLCC.

KPTCL Mail Recieved dated 22-11-2017:

Bus Bar Protection panel and required Wave traps are supplied under R&U. Wave trap to be commisioned in Tandoor line and PLCC

to be restored.Once PLCC is restored AR will be enabled.


1. Replacement of Bus Bar Protection is included under R&U project. Awarded to M/s GE Ltd. Panels have alredy been supplied by

the Agency. The work will be taken up on top priority.

2. AR feature will be enabled during retrofitting of Main-2 relays.


1. Timeline - September 2019

2. Completed


1. The work is under progress, expected to be put in to service before end of February 2020

2. AR was implemented. But due to problem with single phase trip relays the same was disabled. Now the same has been attended

and expected to be put in to service before end of February 2020


1. Bus Bar and LBB Protection has been Commissioned at Sedam SS .




PLCC.

KPTCL Mail Recieved dated 22-11-2017 & 16.12.2017:

1.Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial

lines, it was decided that enabling AR is not required. To clear the faults in the abovelines early, the timings of the Zone 2 was

reduced to 150mS and the Back Up EFR timings have been reducedto 150mS. --- Completed

2.The planned works as per R&M could not be taken up due to the problem with the vendor and could not be taken up under R&U

project due to administrative reasons. ---- Pending


2. The issue was discussed. Considering the importance of the substation and delay in executing the works, it was decided to

escalate all pending issues relating to Ambewadi SS to KPTCL top Management for early completion.


. Ambewadi-Xeldom is a radial line 2). Bus Bar Protection is provided at Ambewadi


The protection issues pertaining to Ambewadi was appraised to the management and proposal for construction of new GIS SUb

stations has been approved by KPTCL management. Further as per SRPC directions and in view of attending protection audit

recommendations pertaining to Ambewadi SS without linking with new Station proposal, action has been taken to include the works

in extended scope of R&U project awarded to M/s GE T&D India Limited. Addition materials required are yet to be supplied by M/s

GE. work expecnted to be completed in 5 months.


1. Since 220kV Ambewadi -Ponda line is radial, this recommendation is dropped.

2. Timeline will be in timated by KPTCL


1. 220kV line breaker replacement work under progress at Ambewadi. AR will implemented after replacement of CBs -- Pending

2. BBP provided at Ambewadi -- Completed

Status?

42/I/2

(GD)

Fault occurred in 220kV Sedam-Shahpur line Pending15-02-2015

at 14:24 hrs


Ambewadi substation of

KPTCL

Fault in 220kV Ambewadi-Nagjheri line-2 Pending

42/I/1 Complete outage of 220kV

Sedam substation of KPTCL

12-03-2015 at 7:51 hrs

1. KPTCL shall provide A/R feature on Ambewadi – Ponda 220 kV D/C inter-state line.



to PCSC forum.

KPTCL

KPTCL

1. KPTCL to provide Bus Bar protection and LBB protection at Sedam S/s and furnish the

status of their implementation to PCSC forum.

2. KPTCL to implement A/R feature on 220 kV Sedam-Tandur inter-state line.

Annexure-C

Page 27 of 52

KPTCL mail received on 23-01-2016:

Will be complied in a months time.


Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial


reduced to 150mS and the Back Up EFR timings have been reducedto 150mS.


Enabling the AR feature was discussed during PCSC meetings and since Ambewadi-Ponda and Ambewadi-Xeldom lines are radial


reduced to 150mS and the Back Up EFR timings have been reduced to 150mS. In view of the above, it is requested to drop the issue

from this list.


KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of

Back Up protection by Distance protection relay at Ambewadi.

Considering the importance of the substation and delay in executing various works, it was decided to escalate all pending issues

relating to Ambewadi SS to KPTCL top Management for early completion.


The protection issues pertaining to Ambewadi was appraised to the management and proposal for construction of new GIS SUb

stations has been approved by KPTCL management. Further as per SRPC directions and in view of attending protection audit

recommendations pertaining to Ambewadi SS without linking with new Station proposal, action has been taken to include the works

in extended scope of R&U project awarded to M/s GE T&D India Limited. Addition materials required are yet to be supplied by M/s

GE. work will be completed in 5 months


1. Work order plced. Timeline requested December 2019.

Status?

48/I/3 Outage of 220kV Ambewadi

station in Karnataka

220kV Ambewadi-Nagjheri line-2 tripped on B-phase to earth

fault. This resulted in loss of supply to 220kV Ambewadi bus.

220kV Ambewadi-Ponda line-1&2 were hand tripped after

deenergization of bus at Ambewadi.

30-09-2015 at 10:41

hrsKPTCL Pending

KPTCL to fast-track providing A/R on all 220 kV lines emanating from Ambewadi SS to

prevent Station shut-down on temporary faults.

Annexure-C

Page 28 of 52

KPTCL Mail received dated 25-04-2017:

Replacement of existing BBP by new BBP with 4 zone protection is being taken up under R&U.


GE Ltd has already supplied the necessary Bus Bar protection panels for replacement of the existing static type BBP by new

numerical BBP with 4 zone protection under R&U project. The work of commissioning the same will be taken up shortly.


Due to operational constraints two/ multi bus operation is not being implemented.


It was noted that Shimoga SS is having required configuration for providing double-bus operation. However, due to large no. of

feeders (15 in no) with variable gneration at certain remote ends like Varahi, the flows on these lines are bound to vary. As such it is

necessary to zero in on appropriate arrangement of feeders on different buses so that bus-isolators of the feeders are not overloaded.

The issue was discussed. KPTCL was asked to try out multi-bus operation on trial basis to arrive at suitable arrangement of feeders.


For Ensuring effective multi zone operation at Shimoga action has been taken to provide Bus sectionalizer breakers (at present only

sectionalizer isolators are provided). The subject work is in tendering stage. Till such time, double bus operation will be put in to

place.


Bus sectionaliser breakers have to be provided for operating Shimoga in multi bus mode. Estimates have to be prepared by

CEE,TZ,Hassan. Work expected to be completed in 1 year.


After commissioning of numerical BBP bus split trial operation was made. However for providing more reliability, action is being

taken for providing bussectionaliser breakers.

KPTCL mail received dated 25.04.2017:

Numerical BBP is being provided under R&M works


Tesing & Commissioning of numerical BBP at Somanahalli is under progress. There was some technical issue wth BBP scheme

supplied to Somanahally which is being finalised in consultation with OEM SIFANG. Numerical BBP will be commissioned at

Somanahally within a month's time.


Numerical Bus Bar protection Scheme will be commissioned at Somanahally before end of December 2017.


The work of providing Bus Bar Protection to 220kV buses is incuded under R&M works envisaged at Somanahally. The R&M

work is expected to be completed before end of March 2019 ----- Pending


status of work and timeline will be given by KPTCL


The work is to be executed by the R&M turn key agency


Pending under R&M project scope


Ambewadi station

02-04-2018 at

13:46hrs

Loss of supply occurred to 220 kV Ambewadi station due to

tripping of 220kV Nagzhari-Ambewadi line-2 (Source) from

Nagzhari power station. After bus dead, Ambewadi-Ponda

lines – 1 & 2 were hand-tripped. In antecedent conditions,

220kV Ambewadi - Nagjheri ckt-1, 220kV Ambewadi-

Narendra Ckt-1 &2 were out of service.

1). KPTCL to review operation of SPS at NPH for proper functionality and changed

network conditions (reduction of generation with tripping of evacuating lines) and put it into

service at the earliest.

2). KPTCL to furnish equipment failure report of the current incident (R-phase CT in

Nagjheri – 1 bay at Ambewadi SS) to PSE&TD Division of CEA with a copy marked to

SRPC.

KPTCL


1). To be reviewed. Expected to be completed in 1 month.---- Pending

2), Being followed ----- Pending


1. Nagjheri SPS shall be studied in view of changed system configuration

2. Completed


The logic is being reviewed by SRLDC by conducting system studies for the changed network configuration


1. Nagazari SPS is revosed 2). Equipment Failure report submitted to CEA

Pending

74/II15Multiple Trippings at

400/220kV Guttur station

21-04-2018 at 12:50

hrs

Triggering incident was fault in 220 kV Davanagare -

Shimoga line. Bus bar protection operated at Guttur resulting

in tripping of all the connected elements. 220 kV Guttur was

on single bus operation due to CVT problem in Bus-2.

KPTCL to put double-bus operation at their 220 kV Guttur substations by attending to Bus-

2 CVT problem.KPTCL


Bus-2 CVT problem is attended. However due to breaker replacement works, 220kV side operated in single bus mode.


KPTCL informed that double-bus operation at their 220 kV Guttur would be provided within two months.


Timeline will be communicated by KPTCL


Attended. Double bus operation is in place in Guttur both on 400kV side and 220kV side.

Pending

62/II/5

52/I/3

KPTCL

KPTCL to operate 220 kV Shimoga on multi-bus operation under normal conditions, and

put it on single-bus operation only under emergency conditions.

KPTCL to provide numerical Busbar Protection at their 220 kV Somanahalli SS at the

earliest.

Tripping of 220 kV South Bus

and connected elements

(220kV HSR, 220kV

Nagnathpura, 220 kV

Harohalli, 220 kV

Subramanyapura, 220 kV

Tataguni, 220 kV Mallur and

400/220kV ICT-2 and 3) at

400/220kV Somanhalli

substation of KPTCL

(Load loss: 850 MW)

20-01-2017 at 14:34

hrs

Pending

Pending

KPTCL22-02-2016 at 15:03

hrs

220kV Bus Bar protection operated during failure of R phase

CT in DVG-2 line bay.

Triggering incident was fault in 66 kV Somanahalli -

Bannerghatta line and fault was cleared by operation of Back-

up OCR at Somanahalli end.


Shimoga substation

Annexure-C

Page 29 of 52

79/III/9Tripping of 400 kV JSWEL

–Guttur line

29-09-2018

at 11:30 hrs

R-phase to earth fault occurred in line. Auto-reclose was not

attempted at JSWEL due to DT receive. At Guttur end auto-

reclose could not be validated with DR/EL.

KPTCL to furnish a detailed report on tripping event bringing out reasons for DT sending

from Guttur end to JSWEL on 400 kV Guttur - JSWEL line along with remedial action

taken to PCSC forum.

KPTCL


KPTCL was aksed to furnish status of implementation of the recommendation given at the earliest.


report will be submitted by KPTCL

Pending

80/II/7Tripping of 400 kV JSWEL-

Guttur line

17-10-2018 at 02:04

Hrs

Triggering incident was R-phase to earth fault in line. At

Guttur end there was operation of pole discrepancy and

resulted on tripping of Y & B pole after a duration of 2

seconds from the occurrence of fault. FIR, DR & EL of

Guttur end were not furnished.

KPTCL to examine the reasons for sending of DT from Guttur end to JSWEL end, and

furnish an action taken report including remedial measures taken to rectify the same.KPTCL


report will be submitted by KPTCLPending

82/I/4Complete Outage of 220kV

Ambewadi Station of KPTCL

06-02-2019 at

14:51hrs

Fault occurred while test charging of 220kV Ambewadi –

Nagjheri Line -2 from Ambewadi end. Suspected stuck

breaker condition at Ambewadi end) led to clearing of fault by

tripping of remote end breaker in Zone-2. LBB protection is

not active at 220kV Ambewadi station.

KPTCL to investigate the reason for non-tripping of 220kV Ambewadi - Nagjheri line-2 on

operation of SOTF and submit a report regarding the same to SRPC. Also KPTCL to take

necessary measures in order to ensure healthiness of breaker before testcharging of any line.

KPTCLReview meeting on 27.06.2019:

report will be submitted by KPTCLPending

84/II/12Tripping of 400kV DHONI

GUTTUR line- 1

18-04-2019 at 18:59

hr.

Triggering incident was failure of B-ph CB of 400kV Dhoni-

Guttur line at Dhoni end. This resulted in the operation of

LBB of bus-1 and DT was sent to Guttur end

1. KPTCL to send equipment failure report, corresponding to the failed CB at Dhoni SS, to

CEA.

2. KPTCL to ensure time synchronization at Guttur end.

KPTCL Yet to be informed Pending

84/II/16Tripping of 400 kV

Nelamangala-Mysore line-201-05-2019 at 02:29 hr.

Line tripped on operation of over voltage stg-2 at

Nelamangala end

KPTCL to ensure time synchronization of DR and EL with GPS signal at Nelamangala

end.KPTCL Yet to be informed Pending

84/II/24Tripping of 400/220 kV ICT-

1&3 at Hoody Substation

13-05-2019 at 15:35

hr.

ICT-3 tripped on operation of 59N neutral displacement relay.

ICT-1 tripped on OCR.

KPTCL to inform PCSC forum regarding the changes implemented in Hoody ICT SPS and

to ensure time synchronization of relays at Hoody SS.KPTCL Yet to be informed Pending

85/I/4

Tripping of 220kV Sedam-RTPS

line-1&2 and 220kV Sedam-

Tandur line

14-06-2019

at 02:00 hrs

Tripped on Directional Earth Fault indications in Main-2 relay

at Tandur end for fault at Raichur end. Sedam end details not

furnished.

1. KPTCL is recommended to enable A/R on all lines emanating from 220kV Sedam SS.

2.KPTCL is recommended to commission BBP at 220kV Sedam SS immediately.KPTCL


The work is under progress, expected to be put in to service before end of February 2020


1). Bus Bar Commissioned at Sedam

Pending

85/II/5Tripping of 400/220 kV ICT-3

at Nelamangala substation

19-05-2019

at 16:11 hrsAs per FIR, ICT-3 got tripped on operation of High Set Over

current trip on 400kV side

1. KPTCL is recommended to enable auto-reclosure on all lines emanating from 400/

220kv Neelamangala SS and to ensure time synchronization of relays at Neelamangala SS.KPTCL Yet to be informed Pending

85/II/11Tripping of 400kV Hoody-

Yelahanka line-1

25-05-2019

at 20:41 hrsLine tripped at Hoody end only and was holding from

Yelahanka.

KPTCL is recommended to check the spurious operation of SOTF protection at Hoody SS

and submit a report to SRPC regarding the same .KPTCL Yet to be informed Pending

85/II/12Tripping of 400/220 kV ICT-1at

Guttur Substation

26-05-2019

at 10:00 hrs LV side of 400kV/220kV 315MVA ICT#1 Guttur got

tripped due to CB lockout (B phase)because of low SF6 gas

in the CB

1. KPTCL is recommended to submit a report to SRPC after the CB pressure leakage

problem is attended by OEM.

2.. KPTCL to ensure that during recharging of Circuit breakers, cylinders with Non-return

valve only are used to prevent sudden pressure drop in Circuit breakers.


85/II/22Tripping of 400kV Dhoni-

Munirabad line

06-06-2019

at 02:01 hrsLine got tripped at Dhoni end. From DR Zone-3 start, PSB

and A/r block was observed.

KPTCL is recommended to submit a report regarding PSB maloperation along-with the

RM suggested by OEM. Proper legends shall be ensured for digital signals at Doni end.KPTCL Yet to be informed Pending

85/II/27Tripping of 400/220kV ICT-2 at

Hoody substation

16-06-2019

at 19:20 hrs ICT-2 got tripped on operation of over-flux protection

KPTCL is recommended to adopt v/f settings as per manufacture suggested curve.

v/f setting for alarm: 1.1 time Vnominal; Time delay 10 seconds;

v/f trip setting : v/f is 1.2 time Vnominal;Time delay 60 secondsKPTCL Yet to be informed Pending

85/II/29Tripping of 400kV Hiriyur-

Nelamangala line-1 and 400kV

Gooty-Nelamangala line

22-06-2019 at

04:06hrs

400kV Hiryur-Nelamangala line-1 : 'Y' phase bushing of

Hiriyur line-1 reactor failed at Nelamangala end resuting in a

R-Y phase fault. Direct trip was sent to Hiryur.

400kV Gooty-Nelamangalaline : Line tripped at Nelamangala

end only due to mal-operation of Main-2 distance protection

relay (THR).

KPTCL is recommended to submit equipment failure report to CEA regarding the reactor

bushing failure and also to sort out time synchronization issues of 400kV Hiriyur-

Nelamangala line.


85/II/30Tripping of 400/220kV ICT-1&2

at Munirabad substation

24-06-2019

at 20:50 hrs

400/220kV ICT-1&2 at Munirabad end got tripped due to

operation of High set of backup earth fault relay during

failure of Y phase CT in 220kV Munirabad-Kalyani steel

feeder at Kalyani steel end

KPTCL is recommended to submit equipment failure report to CEA regarding the CT and

PT failure.KPTCL Yet to be informed Pending

Annexure-C

Page 30 of 52


Neelamangala-Mysore line-2

15-07-2019

at 2:02 hr

line tripped on operation of OV st-1 protection at

Neelamangala end and DT was received at Mysore end. DR

of Nelamangala end was not available for validation of OV

protection operation

KPTCL to configure both OVR start and OVR trip in DR or EL at 400 kV Neelamangala SS.

Time sync issues at 400 kV Neelamangala SS shall also be sorted out immediately.KPTCL


DR triggering has been done for OVR stage-1 operation in Mysore-2 line . GPS time synchronisation of Power Grid bays will be

taken up along with panel replacement work envisaged under R&M.

OVR_start also to be configured.

Pending

Annexure-C

Page 31 of 52


1. coordination of KPCL has been requested for enabling AR lines terminated to Nagajari.

2. AR will be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of Back Up protection by

Distance protection relay at Ambewadi.

KPTCL Mail dadted 16.12.2017 & Review Meeting dated 19.12.2017:

1. KPTCL informed that Coordination of KPCL has been requested for enabling AR lines terminated to Nagajari.

--- Pending

2. KPTCL informed that AR would be enabled at Ambewadi end for lines other than Ponda and Xeldom lines during retrofitting of

Back Up protection by Distance protection relay at Ambewadi. -- Pending


2). Readiness from KPTCL for implementing AR is already confirmed to KPCL. Decision pending from KPCL end.


1). KPCL informed that A/R will be provided on all 22 kV lnies emmanating from Nagjheri PH within 3 months time ----- Pending



IEC61850. Prepration of specification is under progress.


1) Budgetary offer obtained for replacement of existing PZ1000 relays with new version Numerical Line protection relays having

IEC61850. Preparation of estimation and specification is under progress.

KPCL mail dated 25.05.2019 & 16.07.2019:


Phase-II DPR. Approval of NLDC for DPR is awaited. Further, availing administrative approval for issue of NIT for replacement of

existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 and preparation of estimation and

specification is under progress. Timeline for completion of work is July 2020.

KPCL mail dated 30.10.2019


Phase-II DPR. Approval of NLDC for DPR is awaited. NIT issued through e-portal on 16.09.2019. Pre-bid meeting was held on

10.10.2019. Finalising of replies to pre-bid queries is in progress.


2021.

Contract agreement is executed with contractor & drawing approval is completed. Supply portion yet to be completed

KPCL mail dated 17.12.0219 and 11.02.2020:

1) ) Replacement of existing PZ1000 relays with new version Numerical Line protection relays having IEC61850 is included in PSDF

Phase-II DPR. Approval of NLDC for DPR is awaited. NIT issued through e-portal on 16.09.2019. Cover-1 opened on 02.12.2019.

Technical evaluation is in progress.

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:


Phase-II DPR. NIT issued through e-portal on 16.09.2019. Tender evaluation is completed. Approval of NLDC for DPR is awaited



1) Approval from PSDF was received on 31.03.2021. Deatiled order is placed on M/s GE T&D Ltd. work will completed by Dec-

2021.



2021.

Contract agreement is executed with contractor & engineering work is in progress.



2021.

Contract agreement is executed with contractor & drawing approval is completed. Supply portion yet to be completed

KPCL/ KPTCL Pending49/I/3


Ambewadi Substation of

KPTCL

1. KPCL to provide A/R on all 220 kV lines emanating from Nagjheri PH.

2. KPTCL to provide A/R on all 220 kV lines emanating from Ambewadi SS.

220kV Nagjheri-Ambewadi line-1 tripped at 13:33 hrs due to

B phase to earth fault. Ambewadi was radially fed from

Nagjheri power station through 220kV Nagjheri-Ambewadi

line-2. Tripping of this line caused 220kV Bus shut down at

Ambewadi and remaining lines and transformers were hand

tripped

29.10.2015 at 14:34

hrs

Annexure-C

Page 32 of 52

Status informed during Special Meeting held on 03.06.2016:

1. KPTCL informed that the matter had been taken up with concerned Line Operation and Maintenance wing to carry out corridor

clearance and maintenance as per schedule to avoid frequent line faults in this corridor. A letter had also been addressed to Chief

Engineer, Bhagalkot zone, to ensure lines in & around Kali complex are maintained in healthy condition. --- Completed

2. KPTCL assurd that the final modified SPS would be implemented at Nagjheri PH at the earliest. ------ Pending

3. KPCL informed that Nagjhari- Kodasalli Lines 1 & 2 had been kept in service since 23.05.2016 @ 08.06hrs.

--- Completed


2. Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval


1. Will be reviewed in consultation with EE(RT), KPTCL, Hubli.

3. Both the lines are in charged condition.


1) & 3) --- Completed

2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., Yet to be discussed and approved by the

SRPC forum. --- Pending


1) & 3). --- Completed.

2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the

SRPC forum --- Pending


2. The SPS proposed by KPTCL was discussed and the PCSC forum suggested certain changes for suitable incorporation. KPTCL

agreed to look into the same and assured that the modified SPS would be furnished by January, 2018.


2. KPTCL informed that Nagjheri SPS shall be finalised in 1 month.

KPCL mail dated 23.01.2019 & 23.03.2019:

1) .....Completed


3) .....Completed

KPCL mail dated 13.05.2019 & 25.06.2019

1. 3. Completed

2) Letter addressed to KPTCL RT dated: 25.03.2019 for review and implementation of SPS at NPH. Reply is awaited.KPCL mail dated 16.07.2019:

1 & 3) Completed.

2) Letter addressed to KPTCL RT dated: 25.03.2019 for review and implementation of SPS at NPH. Reply from KPTCL is

awaited.


1 & 3) Completed.

2) KPTCL informed that Naghjeri SPS need to be revisited in view of changes in system configuration. Reply from KPTCL is

awaited


1 & 3) Completed.

2. The logic is being reviewed by SRLDC by conducting system studies for the changed network configuration

KPCL mail dated 21.05.2020 & 27.07.2020 & 28.09.2020 & 26.11.2020, 22.01.2021 & 26.05.2021:

1 & 3) Completed.

2) KPTCL informed that Naghjeri SPS need to be revisited in view of changes in system configuration. Reply from KPTCL is

awaited.


1 & 3) Completed.

2) Revised settings is received from CEE RT & R&D vide e-mail dated:08.06.2021 and requested to conduct the functionality check

of the SPS, in co-ordination with RT Division Hubli after revision of limit. Accrodingly, SE(E)N vide letter dated:12.06.2021

addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the necessary settings and check funtionality of the same. Reply

from EE(E)RT, KPTCL, Hubli is awaited


1 & 3) Completed.



addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the necessary settings and check funtionality of the same.

CEERT, KPTCL vide e-mail dated:25.06.2021 has informed tha the NPH Exbus generation limit has been modified from 600MW to

KPCL/ KPTCL51/I/322-02-2016 at 12:36

hrs

220kV lines from Nagjheri power house started tripping from

11:00 hrs due to fault in lines. The sequence of tripping is

shown in SOE list. At 12:33 hrs, 220kV Narendra-Ambewadi

lines-1&2 got tripped which resulted in loss of evacuation

path to Nagjheri station resulting in tripping of running Units

and complete outage at Nagjhheri power station. 220kV

Ambewadi station also got de-energized due to tripping of

source feeders i.e. 220kV Narendra-Ambewadi-1&2 and

220kV Nagjheri-Ambewadi-1&2.


Nagjheri power station and 220

kV Ambewadi substation of

KPTCL

Complied

1. To avoid tripping of transmission lines on transient faults, KPCL/ KPTCL is

recommended to carry out periodic patrolling of lines, and ensure their proper maintenance

by carrying out jungle/ bushing clearance and trimming of tree branches within the RoW of

transmission lines as per the SRPC transmission line patrolling guidelines (available under

the menu item "All Uploads/ Operation/ Miscellaneous/ Transmission Line Patrolling

Protocol / Guidelines for Southern Region" on SRPC website).

2. KPCL/ KPTCL to review operation of SPS at NPH for functionality (reduction of

generation with tripping of evacuating lines) and healthiness.

3. KPCL to put 220 kV Kodasalli - Nagjheri D/C lines into service if more than 200 MW

generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured

on sustained basis.

Annexure-C

Page 33 of 52

KPCL mail dated 23.01.2019 & 23.03.2019:

1) …Completed.


3) …Completed.

KPCL mail dated 10.05.2019 & 25.06.2019:

1. & 3. Completed

2) Letter addressed to KPTCL RT dated: 25.03.2019 for review and implementation of SPS at NPH. Reply is awaited.


2. KPTCL informed that Naghjeri SPS need to be revisited in view of changes in system configuration.

KPCL mail dated 16.07.2019 & 30.10.2019 & 17.12.2019 & 11.02.2020 & 21.05.2020 & 27.07.2020, 22.01.2021,26.05.2021:

1 & 3) Completed.


awaited.


1 & 3) Completed.



addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the necessary settings and check funtionality of the same. Reply

from EE(E)RT, KPTCL, Hubli is awaited-Completed


1. & 3. Completed

2. The logic is being reviewed by SRLDC by conducting system studies for the changed network configuration

KPCL mail dated 21.05.2020 & 28.09.2020 & 26.11.2020 & 22.01.2021:

1 & 3) Completed.


awaited.


Nelamanagala-Mysore line-228-09-2019 at 1:38 hr.

Line tripped on operation of over voltage stg-2 protection at

Nelamangala and direct trip received at Mysore

KPTCL to ensure relay pickup to drop off ratio of 0.98 and above for relays configured for

overvoltage protection.KPTCL Yet to be informed Pending

88/II/14Tripping of 400/220kV ICT-2

at Guttur

22-10-2019 at 02:12

Hr.

ICT#2 at Guttur got tripped on operation of Buchholz

protection due to suspected moisture entry during rain.KPTCL to provide shielding for Buchholz relay to prevent such mal-operations. KPTCL Yet to be informed Pending

18-03-2016 at 14:40

hrs


Modifications to be carried in Nagzari SPS logic is submitted to SRLDC/SRPC for verification and approval


1. Tripped since there was evacuation problem and there were only two lines NA-1 and NA-2 ---- Completed

2. Will be reviewed in consultation with EE(RT), KPTCL, Hubli. --- Pending

3. Both the lines are in charged condition. --- Completed.


2. Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the SRPC

forum. --- Pending


1) & 3). --- Completed.

2). Proposed revision in existing SPS scheme is already submitted to SRLDC/SRPC., yet to be discussed and approved by the

SRPC forum --- Pending


2. The SPS proposed by KPTCL was discussed and the PCSC forum suggested certain changes for suitable incorporation. KPTCL

agreed to look into the same and assured that the modified SPS would be furnished by January, 2018.


KPTCL informed that Nagjheri SPS shall be finalised in 1 month.


1 & 3) Completed.



addressed to EE(E) RT, KPTCL, Hubli division requesting to revise the necessary settings and check funtionality of the same.

CEERT, KPTCL vide e-mail dated:25.06.2021 has informed tha the NPH Exbus generation limit has been modified from 600MW to

300MW in SPS logic built at NPH and no other changes are made in the SPS logic The said changes are made on 25th June 2021 at

CompliedKPCL/ KPTCL53/I/3

Ambewadi Narendra line-2 tripped on fault and 220kV

ambewadi Narendra line-1 tripped due to over-loading.

Running Units at Nagjheri also tripped during the event due to

tripping of evacuating lines


Ambewadi station of KPTCL

and 220kV Nagjheri of KPCL

1. KPCL to furnish a report on the reasons for Unit-6 tripping at Nagjheri PH.

2. KPCL/ KPTCL to modify suitably the SPS at Nagjheri Power House such that it would

also factor in the over loading of Ambewadi-Narendra lines.

3. KPCL to put 220 kV Kodasalli - Nagjheri D/C lines into service if more than 200 MW

generation from Kali Complex (with Nagheri Contribution not less than 50 MW) is ensured

on sustained basis.

Annexure-C

Page 34 of 52

89/I/1

Complete loss of supply at 220

kV Hubli SS, 220 kV Bidnal

SS of KPTCL and 220 kV

Nagjheri GS of KPCL

14-12-2019 at 10:56

Hr.

• Triggering incident was fault in 220 kV Hubli-Narendra Line-

2.

• Due to cascaded tripping of connected lines and loss of

evacuation, there was complete loss of supply at:

220 kV Bidnal SS of KPTCL and

i. KPTCL to ensure A/R is in service in all 220 kV lines emanating from 220kV Hubli SS

and 220kV Bidnal SS.

ii. KPTCL was requested to ensure proper planning of outages of transmission lines (i.e.,

outage planning should be as per N-1 contingency planning and not to cause stress on the

system to avoid complete outages due to fault in the Nagjhari- Hubli corridor.

iii. KPTCL to explore the possibility of split bus operation at 220 kV Hubli SS, in the event

of outage of any of the 220 kV Hubli – Narendra line, to prevent overloading of other line

(Narendra line) and 220kV Bidnal – Narendra line.

iv. KPTCL to submit the SPS for shedding of loads planned at 220kv Hubli SS.

v. KPTCL to expedite finalization of SPS at 220kV Nagjheri SS considering LILO of one

circuit of 220kV Haveri-Narendra line at Bidnal as part of RE evacuation and submit the

study to SRPC and SRLDC for scrutiny/ finalisation.

vi. KPTCL to ensure time synchronization of relays at 220kV Hubli, 220kV Bidnal, 220kV

Soundatti and 220kV Harthi.

vii. KPTCL to explore the possibility of conductor strengthening in Nagjheri – Hubli- Bidnal

and surrounding areas.

KPTCLKPTCL vide mail dated 22.05.2020 informed that

Recommendations made by SRPC on this incident are communicated to various wings. Action taken details/latest status is yet to be

received. The same will be complied to SRPC upon receipt of confirmation from different wings

Pending

89/1/2Complete loss of supply at 220

kV Shimoga SS of KPTCL.

25-12-2019 at 17:44

Hr.

Triggering incident was line to line fault in 220 kV Shimoga-

Sharavathi line -4.

Bus-1 Bus bar protection operated at 220 kV Shimoga

resulting in complete loss of supply since all the elements

were connected to Bus-1 during antecedent conditions.

i. KPTCL to ensure Double Bus operation at 220 kV Shimoga SS to ensure reliability to

prevent complete outage of Substation.

ii. KPTCL, in coordination with KPCL, to enable A/R in 220 kV Shimoga – Sharavathy

lines.

KPTCL Pending

89/III/1Tripping of 400kV Kaiga –

Guttur Line-2

11-10-2019 at 08:49

Hr.

And

26-10-2019 at 12:42

Hr.

• Triggering incident was Y phase to Earth fault in the line.

• At Kaiga end, fault was detected in zone-1, A/r operated

successfully.

• At Guttur end, fault was sensed in zone-1 and A/r not

operated.

• Non operation of A/r at Guttur end needs review.

• KPTCL to study the A/R block signal issued due to misinterpretation of single phase fault

as multi phase fault by distance relay (P442) and take suitable remedial actions.KPTCL

KPTCL vide mail dated 22.05.2020 informed that SEE, RT Circle,Chitradurgain coordination with EEE,Guttur to arrange for

checking the healthiness of AR scheme for Guttur-Kaiga linesPending

90/I/8Complete outage of 220kV

Shimoga station of KPTCL

19-03-2020 at 17:08

Hr.

During antecedent conditions, all the elements were connected

to Bus-1 North bus at 220kV Shimoga SS. Triggering incident

was R –N fault in 220kV Shimoga - Varahi line-2 due to

insulator decapping. At the same time, 220kV Bus-1 BBP

maloperated at 220kV Shimoga SS. All the elements were

connected to Bus-1, which resulted in the complete loss of

supply at 220kV Shimoga SS.

KPTCL to take necessary measures to prevent mal operation of BBP at Shimoga during

single-ph to line fault and ensure double bus operation at 220kV Shimoga SS.KPTCL


1). Attended. The issue is rectified with IEM Support and BBP is put back to service.Pending


Peenya SS of KPTCL9-05-2020 at 06:29Hrs

• Triggering incident was snapping of earth conductor at

second tower from 400 kV receiving station Nelamangala.

• All other connected lines at 220kV Peenya tripped resulting

in complete outage of 220kV Peenya station

KPTCL to share the details of BBP commissioning schedule. KPTCL Yet to be informed Pending

91/I/9

Multiple Tripping in

400kV/220kV Tumkur SS and


Anthrasanahalli SS of KPTCL

18-05-2020 at

10:14Hrs

• At 10:10hrs, 220kV Tumkur -_PGA’halli line was taken

under shutdown for AMP works.

• At 10:14hrs, bus fault occurred at 220kV Tumkur_PG SS

due to inadvertent closure of Bus-1 Earth Switch of A’halli

line-2 while Bus-2 isolator of A’halli line-2 was in closed

condition.

• Due to non-operation of BBP at 220kV Tumkur_PG SS,

fault was cleared by tripping of remote end feeders on Zone-2

operation and 400kV/220kV Tumkur ICT-1, 2 and 3 got

tripped on operation of HV side directional OC protection.

• This resulted in de-energization of 220kV Tumkur_PG bus.

• Since 220kV A’halli SS was radially fed from 220kV

Tumkur_PG SS, this resulted in complete loss of supply at

220kV A’halli SS of KPTCL .

KPTCL is recommended to check the distance zone settings at 220kV KIADB SS since, it

picked up in Zone-1 for a fault in remote station.KPTCL Yet to be informed Pending

91/I/10Complete loss of supply at

220kV Manyata and 220kV

Hebbal SS of KPTCL

24-05-2020 at

14:55Hrs

• 220kV Manyata - Yelanhanka line tripped on Zone-1,

distance protection due to R-Y fault.

• As reported at tower location 67, tarpaulin sheet fell on the

line.

• Since the only incoming source to 220kV Hebbal was from

Manyata, tripping of 220kV Manyata - Yalahanka line

resulted in complete loss of supply at 220kV Manyata and

220kV Hebbal stations of KPTCL.

KPTCL to explore the possibility of providing double bus at 220kV Hebbal SS. KPTCLKPTCL Mail dated 12-10-2021

1).Due Space constraints it is not feasible. SRPC is requested to drop this observation

Due to space constraits

providing double bus

arranement is not

possible at Hebbal.

SRPC is requested to

drop this particular

observation.

Annexure-C

Page 35 of 52


Nandihal SS, Bijapur SS, and

Indi SS

17-Oct-20

22:35 hrs

Triggering incident was failure of

Y-ph Metering CT connected to Nandihal - GM Navara line-

1. Bus bar protection operated at 220kV Nandihal station and

all connected elements tripped. There was supply failure at

220kV Indi and Bijapur stations, since these station are

radially fed from 220kV Nandihal station.

i. M/s. Gamesa Ltd./KPTCL to restore Double bus operation at 220kV Nandihal SS after

replacing failed bus coupler CT.

Ii. M/s. Gamesa Ltd./KPTCL to submit Equipment failure report for failed CT to CEA with

a copy to SRPC

KPTCL Yet to be informed


Narendra Substation of KPTCL

31-Oct-20

23:47 hrs

Triggering incident was CT Blast in Bus-coupler bay at 220

kV Narendra SS. All connected elements at 220 kV Narendra

station tripped on Bus bar protection resulting in complete

outage of the station

KPTCL to expedite restoration of double bus operation, and ensure time synchronisation of

relays at their 220/ 110 kV Narendra SS.KPTCL Yet to be informed

95/I/8


Tataguni SS and 220kV

Vrushabhavathy SS of KPTCL

12-02-21

13:20 hrs.

Triggering incident was line to line fault in 220kV

Somanahalli - Tataguni line. Line tripped at both the ends on

operation of distance protection. At the same time, 220kV

Vrushabavathy - Tataguni line tripped only at Tataguni end.

Due to tripping of 220kV incoming lines, there was complete

loss of supply at 220kV Tataguni SS and 220kV

Vrushabhavathy SS.

BWSSB to provide Main-2 distance protection relay for 220kV Tataguni-Vrishabhavathy

line at 220kV Tataguni end.BWSSB Yet to be informed Pending

95/I/11


Nagjheri PH , 110kV Supa PH

of KPCL and 220kV

Ambewadi SS of KPTCL

25-02-21

13:16 hrs.

Triggering incident was B-E fault in 220kV Naghjeri-Hubli

line-2. (220kV Naghjeri -Hubli line-3 went out around 11:30

hrs.) 220kV Naghjeri – Bidnal lines also got tripped on B-E

fault. Then, 220kV Naghjeri - Hubli line-1 got tripped on

operation of over-current protection. Due to tripping of

evacuating lines, running units # 2, 5 and 6 at Naghjeri got

tripped on operation of over frequency protection. This

resulted in complete loss of supply at 220kV Nagjheri PH,

110kV Supa PH and 220kV Ambewadi SS.During antecedent

conditions, 220kV Ambewadi SS was radially fed from

220kV Naghjeri PH due to outage of 220kV Ambewadi -

Narendra lines.

KPCL to take steps to enable A/R on all 220 kV lines emanating from 220 kV Nagjheri GS. KPCL


It is confirmed that point no.ii action will be intiated during line is taken under NFBC. This point may be treated as Closed.


Approval from PSDF was received on 31.03.2021. Detailed order is placed on M/s GE T&D Ltd. work will completed by Mar-2021.


Supply portion is completed


Approval from PSDF was received on 31.03.2021. Detailed order is placed on M/s GE T&D Ltd. work will completed by Mar-2021.


Supply portion is completed.

Erection, testing & commisioing work is proposed to be taken in Mar-2022

Pending

Rec. ii Closed

95/II/9

220 kV Bus-1 outage at

400/220 kV Hoody SS of

KPTCL

25-01-21

00:42 hrs.

Triggering incident was R phase PT failure of Bus-1 at 220kV

Hoody SS. All the elements connected to Bus-1 got tripped at

220kV Hoody Bus-1. 400kV Hoody-Devanahalli line-1 also

got tripped during this event

KPTCL to expedite commissioning of BBP for 220kV bus at their 220/ 110/ 66kV Hoody

substation.KPTCL Yet to be informed Pending

95/III/8Tripping of 400 kV Gooty -

Neelamangala Line

28-Feb-2021 14:18

hrs.

Triggering incident was Y-E fault in the line at a distance of

244kM from Gooty end. At Gooty end, fault was sensed in

Zone-2 and carrier was received. A/R operated and line

tripped on persistent fault. At Nelamangala end, Zone-1

protection operated and line got tripped. A/R did not operate

KPTCL to ensure that the problem with auto-reclosure of the line is rectified in two weeks

time.KPTCL Yet to be informed Pending

96/I/12

Complete outage of 220/33kV

KSPDCL SS no-4 (Pavagada)

of KSPDCL on 02-05-2021

02-05-2021 09:23

hrs.

During antecedent conditions, all elements were connected to

Bus-1 at 220 kV KSPDCL SS no-4 due to prolonged outage

of Bus-2 because of Bus PT failure issue (since 4 to 5

months).

Triggering incident was fault in 33kV cable no.11 (KREDL)

of 220/33 kV KSPDCL SS no-4. Earth fault protection and

Over current protection operated and line got tripped.

Immediately, 220kV Bus-1 BBP mal-operated resulting in the

tripping of all the elements connected at 220kV KSPDCL SS

no-4. This resulted in complete outage of 220kV KSPDCL SS

no-4.

It may be noted that 220kV Pavagada KSPDCL SS no-4 line

was holding at Pavagada end during this event.

1. KSPDCL to take steps to restore double bus operation at their KSPDCL4 station in a

month’s time.

2. KSPDCL to submit a detailed report on the GD covering all salient issues including the

remedial action taken to prevent recurrence of such events.

KSPDCL Yet to be informed

Annexure-C

Page 36 of 52

97/I/10

Complete outage of 220/66 kV

Kolar SS, 220/66 kV Malur

SS, 220/66 kV Sarjapur SS,

220/66 kV Vikas Tech park of

KPTCL

03-07-2021, 14:40 hrs.

Triggering incident was flashover of LV side R-phase bushing

of 220/66 kV Transformer-2 at 220/66 kV Kolar SS.

Immediately, the transformer caught fire, and all the lines

connected to Kolar SS were hand tripped. Since 220kV/66kV

Malur SS, 220kV/66kV Sarjapur SS, 220kV/66kV Vikas

Tech park were radially fed from Kolar SS, outage of Kolar

SS resulted in complete outage of all these substations.

KPTCL to submit a detailed Action Taken Report w.r.t. the Fire Incident at their 220/ 66

kV Kolar SS including the measures proposed at this substation and other similar

substations to avoid recurrence of such incidents in future.

KPTCL Yet to be informed

98/II/29

Tripping of

220kV/33kV

KSPDCL SS-4

PTR- 1 and 2

03-09-2021,

15:24hrs

220kV/33kV KSPDCL SS-4 PTR-1

and 2 got tripped due to suspected mal-operation.

KSPDCL to furnish a detailed report on the tripping of 220kV/33kV KSPDCL SS-4 PTR- 1

and 2 on 03.09.2021 for fault on 33 kV feeder, and the remedial action taken by them to

prevent such events in future

KSPDCL Yet to be informed

Tamil Nadu

TANGEDCO Pending (ii)25-01-2017 at 22:36

hrs


1) New Relay is tested and ready for replacement.Now all 5 units are in service.The relay will be replaced when lesser units are in

service. --- Pending

2.a)Steps are taken to renovate & mordernization of all the control panel into Numerical based control panels. --- Pending

2.b) Since 230 KV indoor switchyard has no spare space providing dual CT`s is not fessible. -- Completed

3) Procurement of EL & DR is under progress. --- Pending


1) Check zone New Relay is replaced on 17.04.2017 -- Completed.

2. --- Pending

3. --- Pending


2).P & C wing gives clearance to TTPS to procure the Bus bar protection relays and protection relays and SER / DR system vide

Lr.CE/P&C/SE/D/EEPC4/AEE3/F.TECH/D.27/17 Dated: 05.10.2017. To get administrative approval budgetary offer has bar

protection relay from various companies ----Pending

3). SRPC vide Lr: SRPC/SE- III/CEA/2017/6450/DT:27.10.2017 gives features of SER/DR. Budgetary offer will be called for SER

/ DR having above features. ---Penidng


2) & 3) The issue was discussed and TANGEDCO was asked to provide time-line for implementing the recommendations.

Mail dated 29.01.2018:

Procurement work is under progress and will be completed by December 2018.


TANTRANSCO informed that Tender would be floated by January 2019 and Procurement is expected by APril 2019. Works would

be completed by December 2019.


2. Tender issued. Timline- July 2020.

3. Tender has to be issued. Timline- July 2020.

62/II/7

1. TANGEDCO to replace existing Check-Zone relay with a new one possessing required

performance.

2. TANGEDCO to take steps to provide numerical busbar protection at their 220 kV

Tuticorin TPS. TANGEDCO may also explore providing dual CT’s (on either side) for all

B/S breaakers at the time of commissioning of numerical BBP, if there were no space

constraints.

3. TANGEDCO to take steps to provide for standalone Event Logger (EL) and standalone

Disturbance Recorder (DR) with automatic downloading facility to a centralized server.

Failure of Bus Section-I Y-ph CT resulted in operation of bus-

bar protection for Bus Sections -I & II. Running Units#1, 4

and 5, 230 kV Kayathar, 230kV Kudankulam, 230kV Sterlite,

Station Transformer-1, 2 & 3 got tripped during the incident.

Unit – 2 & 3 were not in service.

Tripping of running Units &

230kV feeders at Tuticorin

TPS of TANGEDCO

(Gen Loss: 640 MW)

Annexure-C

Page 37 of 52

Mail dated 18.07.2019

2) Tender has been lodged two times. New indent was reaised on 06.07.19. and tender floating is expected by August 2019.

3) Tender has been lodged on 15.07.19 and new indent would be raised for the same shortly.

TANGEDCO mail dated 17.12.2019 and 12.02.2020:

2) e - tender has been opened on 26.11.19 and placing of purchase order is expected by January 2020.

3) New Indent was raised on 26.08.19 and procurement is undr progress.


2)For busbar protection relays: Placing of purchase order is expected by the end of this month and delivery period is 80 days from

the date of issuing of PO.After the supplying of materials, the replacement work will be taken up during possible 230kV Bus LC. -

-Pending

3) For Stanalone Disturbance Recorder: Specification approval has been sought from our HQ for floating of the tender on

23.12.2019. Again,Reply was sent on 03.02.2020 for the clarification raised by HQ. After obtaing of the approval from HQ, tender

will be floated. - Pending


2.) 3 nos. electromechanical relays were replaced with M/s Siemens make high impedance differential relays and commissioned on

25.11.2020 in Bus A, Bus B and check zone. Balance 03 nos. of relays will be replaced in due course.

3). e-tender opening date is rescheduled on 05.12.2020 .

TANGEDCO letter/mail dated 06/08.03.2021:

Automate Disturbance Records Collection System & Remote Accessibility System (ADRCS&RAS) was installed and commissioned

at TTPS on 27.02.2021.

All the feeder relays and numerical relays in various equipment of switchyard 1 & 2 (tola of 24 relays) are connected with this

ADRCS & RAS.

All the relays in the switchyard 1&2 are time synchronised with GPS.

DR collection and remote parameterization were checked for all relays.

Remote accessibility from central server ensured.

TANGEDCO Mail dated 01.02.2022

2) Exixting electromechanical type bus bar protection relays has already been replaced with M/s Siemens make ,7SR23 model

numerical relays in 230kV main bus I,II,III,IV & Check zone.Recently, Remaining one relay was repalced in Main bus V on TANTRANSCO Mail received on 19-02-2016 and 24-03-2016:

Revision of Bus Bar Protection setting was carried out. The stabilizing voltage setting was raised from 410 to 450 volts. After

completing the necessary test, the bus bar protection put in to service on 29.12.2015.

Mail Received on 27-04-2016 ,16-06-2016,25-07-2016 & 24-09-2016:

Revision of Bus Bar Protection setting was carried out. After completing the necessary test, the bus bar protection put in to service

on 29.12.2015.

Mail received on 10-11-2016 & 20.12.2016:

Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP

through PSDF.

Numerical relay allotted and being commissioned.


Numerical BBP relay was commissioned on 02.02.2017

Status received vide mail dated 12.04.2017 & 01.06.2017 & 15-06-2017:

Numerical BBP relay was commissioned on 02.02.2017.

Provision of Bus Coupler bay arrangement was included in the Upgradation works proposed and the same was sanctioned by MoP

through PSDF.


Numerical BBP relay was commissioned on 02.02.2017.

Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided.

Status received vide mail dated 18-09-2017 & 31-20-2017:

Numerical BBP relay was commissioned on 02.02.2017. Provision of CT in Bus Coupler bay is arranged and zone segregation will

be provided.

Status received vid email dated 12-12-2017:

Numerical BBP relay was commissioned on 02.02.2017. Provision of CT in Bus Coupler bay has been allotted. Zone segregation will

be provided after commissioning of CT.


TANTRANSCO informed that the recommendation would be complied with by March, 2018.

TANTRANSCO Mail received on 25-01-2018:

Provision of CT in Bus Coupler bay is arranged and zone segregation will be provided. Timeline: March-2018.

TANTRANSCO MAIL DATED 22.05.2018 & 08.06.2018:

Bus coupler bay equipments allotted will be commissioned by Aug 2018

TANTRANSCO MAIL DATED 23.07.2018:

Commissioning of CT in Bus Coupler bay is under progress


Commissioning of CT in Bus Coupler bay is under progress Will be completed by Oct.2018.

TANGEDCO

TANTRANSCO50/I/3

Pending (ii)

Pending

25-01-2017 at 22:36

hrs62/II/7

1. TANGEDCO to replace existing Check-Zone relay with a new one possessing required

performance.

2. TANGEDCO to take steps to provide numerical busbar protection at their 220 kV

Tuticorin TPS. TANGEDCO may also explore providing dual CT’s (on either side) for all

B/S breaakers at the time of commissioning of numerical BBP, if there were no space

constraints.

3. TANGEDCO to take steps to provide for standalone Event Logger (EL) and standalone

Disturbance Recorder (DR) with automatic downloading facility to a centralized server.


Mywadi station of

TANTRANSCO

TANTRANSCO to examine the feasibility of providing two main-zone operation for bus bar

protection by exploring various alternatives like replacing existing bus-coupler CB with a

hybrid bus-coupler CB that comes with inbuilt CT, replacing existing BBP relay with

another suitable relay that supports two main-zone operation, and implement the same.

Busbar protection got operated for a fault in 230kV Mywadi-

Anaikadavu line21-12-2015 at 6:28 hrs

Failure of Bus Section-I Y-ph CT resulted in operation of bus-

bar protection for Bus Sections -I & II. Running Units#1, 4

and 5, 230 kV Kayathar, 230kV Kudankulam, 230kV Sterlite,

Station Transformer-1, 2 & 3 got tripped during the incident.

Unit – 2 & 3 were not in service.

Tripping of running Units &

230kV feeders at Tuticorin

TPS of TANGEDCO

(Gen Loss: 640 MW)

Annexure-C

Page 38 of 52


Civil work completed & CT will be commissioned after strengthening Bus .2 conductor jumpers.Awaiting Bus LC Time line before

January 2019.


Erection under progress will be completed before 31.01.2019


Buscoupler bay will be commissioned by June 2019


Buscoupler bay configuation in BBP will be completed by June 2019. Bus segregation will be ensured by 31.12.2019 after attending

Isolator status feedback.


Buscoupler bay configuation in BBP will be completed by June 2019. Bus segregation will be ensured by 31.12.2019 after attending

Isolator status feedback.


Busbar protection with Zone segregation work have been completed . Double bus operation can be done after strengthening of bus

(Twin Moose to Quad Moose). Time line requested upto 30.06.2020.

TANTRANSCO mail dated 20.05.2020 & 07.07.2020 & 28.09.2020 & 11.11.2020:

Busbar protection with Zone segregation work have been completed . Double bus operation can be done after strengthening of bus

(Twin Moose to Quad Moose). Time line requested upto 31.12.2020.


Strengthening of bus (Twin Moose to Quad Moose) programmed on 24.01.2021 Time line requested upto 31.01.2021. for

implementation of double bus operation

TANTRANSCOmail dated 28.04.2021, 28.05.2021:

Time line requested upto 30.09.2021


Bus coupler Breaker & CT commissioned. In Relay two zone feature enabled. Bus Strengthening & Bus Isolator replacement to be

completed in ICT.1 ( bus isolator) & awaited Line clear for executing the work.

Time line requested upto 31.12.2021.



completed in ICT.1 ( bus isolator) & awaited Line clear for executing the work.

Time line requested upto 30.06.2022.

TANTRANSCO50/I/3 Pending


Mywadi station of

TANTRANSCO

TANTRANSCO to examine the feasibility of providing two main-zone operation for bus bar

protection by exploring various alternatives like replacing existing bus-coupler CB with a

hybrid bus-coupler CB that comes with inbuilt CT, replacing existing BBP relay with

another suitable relay that supports two main-zone operation, and implement the same.

Busbar protection got operated for a fault in 230kV Mywadi-

Anaikadavu line21-12-2015 at 6:28 hrs

Annexure-C

Page 39 of 52

The issue was discussed in PCSC-58 meeting held on 18.10.2016, when PCSC forum agreed to de-link the implementation of the

Item from the scope of Protection Audit Recommendations (PAR), and pursue it as part of PCSC Recommendations.

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 &15-06-2017 & 04.08.2017 & 18.09.2017 & 31-10-

2017& 12-12-2017:

Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner.


TANTRANSCO informed that the recommended works of providing different make Relays for Main-I & Main-II are targeted to be

completed by September, 2018.

TANTRANSCO mail received on 25-01-2018:

Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner. Timeline: September-

2018.


TANTRANSCO informed that the recommended works of providing different make Relays for Main-I & Main-II are targeted to be

completed by September, 2018.


provision of Different make Relays for Main-I & Main-II will be completed by September, 2018.



2018.



2019.

TANTRANSCO MAIL DATED 11-12-2018:


2019



2019.



2019


Different make Relays will be provided for Main-I & II relays at Sunguvarchatram end in a phased manner. Timeline: June 2020.

TANTRANSCO mail dated 20.05.2020 & 15.06.2020 & 28.09.2020 & 11.11.2020, 18.01.2021 & 28.04.2021, 28.05.2021:

Since this subatation is SAS SS, the integration of other make relays attracts huge financial implication.Hence this recommendation

may be dropped. So far there is no missing operation / other issues due to same make reay in this substation.

TANTRANSCO mail date 17.07.2021:






14-09-2016 at

11:13Hrs

Bus Bar Protection (Zone-2) of 230 kV Bus-B got operated at

Alamathy Station during fault in 230 kV Alamathy-Korattur

feeder.


Alamathy Station

1. TANTRANSCO to check the healthiness of BBP relay by conducting stability test, and

take appropriate remedial action like increasing voltage settings, ensuring the healthiness of

CT’s, using CT’s with similar characteristics (equal saturation effects & equal winding

resistances) etc. at their 230 kV Alamathy SS.

2. TANTRANSCO to replace the existing high-impedance BBP relay with its low-

impedance/ numerical variant so as to accommodate variation in CT characteristics at their

230 kV Alamathy SS.

PendingTANTRANSCO

Mail received on 10-11-2016 & 20.12.2016:

1. The Bus Bar Protection scheme will be tested for healthiness including the CT circuits.

2. High impedance BBP relay will be replaced by Numerical relay.

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 & 15-06-2017:

1. The Bus Bar Protection scheme was tested for healthiness including the CT circuits. AREVA make CTs in Alamathy SS are

having different kneepoint voltage for the cores. CT cores of higher knee point voltage has been choosen for BBP in 230kV

Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on 29.11.2016. ---- Completed.

2. High impedance BBP relay will be replaced by Numerical relay. --- Pending,

Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017 & 12-12-2017.

1. ---- Completed

2. High impedance BBP relay will be replaced by Numerical relay. --- Pending


2) TANTRANSCO informed that Numerical BBP would be provided by April, 2018 --- Pending


1. --- Complied.

2. High impedance BBP relay will be replaced by Numerical relay. Timeline: April-2018.

TANTRANSCO MAIL DATED 22.05.2018 & 08.06.2018 & 23.07.2018:

2.Numerical BBP relay will be provided. Timeline: Sep-2018.


1. Complied


TANTRANSCO MAIL DATED 06-10-2021

Numerical relay procurement under progress

58 TANTRANSCO

Pending-

TANTRANSCO

Request to drop the

recommendation was

discussed in PCSC-98.

TANTRANSCO was

requested to comply

with the

recommendation.

Different type and Make of distance protection relays to be provided for Main-I & Main-II protection for 230kV feeders at 400 kV Sunguvarchathiram & 230 kV Sunguvarchathiram Substation [Carry-Over from

Protection Audit Recommendations]

Annexure-C

Page 40 of 52

TANTRANSCO MAIL DATED 11-12-2018 & 23.01.2019:

Numerical BBP relay to procured. Timeline: Sep-2019.


Numerical BBP relay to be procured. Timeline: Sep-2019.


Timeline requested upto July 2020.


Timeline requested upto July 2020.

TANTRANSCO MAIL DATED 29.05.2020 & 07.07.2020 & 28.09.2020 & 11.11.2020, 18.01.2021 & 28.04.2021, 28.05.2021

& 17.07.2021:




15-09-2016 at 22:14

hrs


Alamathy Station

1. TANTRANSCO to check the healthiness of BBP relay by conducting stability test, and

take appropriate remedial action like increasing voltage settings, ensuring the healthiness of

CT’s, using CT’s with similar characteristics (equal saturation effects & equal winding

resistances) etc. at their 230 kV Alamathy SS.

2. TANTRANSCO to replace the existing high-impedance BBP relay with its low-

impedance/ numerical variant so as to accommodate variation in CT characteristics at their

230 kV Alamathy SS.

Pending

Bus Bar Protection (Zone1) of 230kV Bus-A got operated at

Alamathy Station during fault in 230 kV Alamathy-OPG-1

feeder.

TANTRANSCO

Mail received on 10-11-2016 & 20.12.2016:

1. The Bus Bar Protection scheme will be tested for healthiness including the CT circuits.

2. High impedance BBP relay will be replaced by Numerical relay.

Status received vide mails dated 10.01.2017 & 12.04.2017 & 01.06.2017 & 15-06-2017:

1. The Bus Bar Protection scheme was tested for healthiness including the CT circuits. AREVA make CTs in Alamathy SS are

having different kneepoint voltage for the cores. CT cores of higher knee point voltage has been choosen for BBP in 230kV

Korattur, 230kV OPG-1 & 230kV OPG-2 feeders on 29.11.2016. ---- Completed.

2. High impedance BBP relay will be replaced by Numerical relay. --- Pending,

Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017 & 12-12-2017.

1. ---- Completed

2. High impedance BBP relay will be replaced by Numerical relay. --- Pending


2) TANTRANSCO informed that Numerical BBP would be provided by April, 2018 --- Pending


1. --- Complied.

2. High impedance BBP relay will be replaced by Numerical relay. Timeline: April-2018.




1. Complied


TANTRANSCO MAIL DATED 06-10-2021


Annexure-C

Page 41 of 52

64/1/4Complete outage of North

Chennai TPS STG-1

26-03-2017

at 23:14hrs

Tripping of evacuating lines due to fault led to tripping of

running Unit at NCTPS Stg-1

1. TANTRANSCO to take steps to complete insulator replacement works on the 230 kV

lines owned by them in NCTPS area within 6 months.

2. TANTRANSCO to take steps to implement A/R on all 230 kV lines emanating from

NCTPS-I at the earliest.

TANTRANSCO

Status received vide mails dated 04.08.2017 & 18.09.2017 & 31-10-2017:

1. All the Porcelain insulators were replaced with Polymer insulators in 230kV NCTPS-I - Tondiarpet feeders - 1 & 2.

---- Completed

2. AR will be implemented on all 230kV lines emanating from NCTPS-I. --- Pending


1. Completed

2. The scheme needs modification to enable AR, since AR was not envisaged for this station during commissioning. AR will be

implemented on all 230kV lines emanating from NCTPS-I within six months. --- Pending


2) TANTRANSCO informed that A/R would be implemented on all 230 kV lines emanating from NCTPS-I by June, 2018.


1. Complied.


implemented on all 230kV lines emanating from NCTPS-I within six months. Timeline:June-2018.

TANTRANSCO mail dated28.05..2021::

1. Insulator replacement (Polymer insulator in place of Porcelain Insulator) in all the 230 kV #s emanating from the NCTPS 230 kV

Switchyard in the vulnerable areas has been completed.

TANTRANSCO mail dated 17.07.2021:,06-10-2021







Pending



implemented on all 230kV lines emanating from NCTPS-I Timeline:Sep -2018.


1. Complied.


implemented on all 230kV lines emanating from NCTPS-I Timeline:Sep -2018.


AR implemented for 4 feeders and remaining lines will be provided with AR subsequently.


1. Complied

2. AR enabled for 3 feeders.


1. Complied

2. AR enabled for 5 feeders.

TANTRANSCO MAIL DATED 11-12-2018:

2. Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem, Tondiarpet & Alamathy feeder . static relay to be

replaced. Timeline - 1 year


Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem, Tondiarpet & Alamathy feeder . static relay to be

replaced. Timeline -Sep 2019



replaced. Timeline -Sep 2019

Annexure-C

Page 42 of 52


1. (i). Polymer insulators has been provided in all the 400 kV evacuation lines from NCTPS end up to 5 KMs. Replacement of

Polymer insulator in 230 kV lines are under progress for the 230 kV lines emanating from NCTPS.

2. Enabling AR pending for 3 feeders. ( Sriperumpudhur end breaker problem, Tondiarpet & Alamathy feeder . static relay to be

replaced. Since the CBs and the Control & Relay Panels (CRP) are very old and commissioned during 1993. The Distance relays

even though are numerical due to ageing its display and resetting keys are faulty. Hence it is proposed to replace the CBs & CRPs

with new CBs and Protection relay panel with SAS. A.R will be put into service after replacing the CB & CRP.

TANTRANSCO mail dated 07.07.2020 & 28.09.2020 & 11.11.2020:


replaced. Since the CBs and the Control & Relay Panels (CRP) are very old and commissioned during 1993. The Distance relays

even though are numerical due to ageing its display and resetting keys are faulty. Hence it is proposed to replace the CBs & CRPs

with new CBs and Protection relay panel with SAS. A.R will be put into service after replacing the CB & CRP.

.

TANTRANSCO mail dated 18.01.2021 & 28.04.2021:

1. Insulator replacement (Polymer insulator in place of Porcelain Insulator) in all the 230 kV #s emanating from the NCTPS 230 kV

Switchyard in the vulnerable areas has been completed. -- Complied

2. Pending


1. At present Duobias relay avaiable I/O configuration could not be carried out.after changing the relay Digital signals will be

configured

2.COMPLIED

3.Provision of Numerical BBP relay covered under R&M work. Tender under progress.

4.out of 30 CTs, 21 No CTs have been replaced with new one.


1. , 3. Timeline requested upto July 2020.

2. Complied

4. Timeline requested upto September 2019.



configured

2.COMPLIED



TANTRANSCO mail dated 11.11.2019 and 12.02.2020:


configured

2.COMPLIED



TANTRANSCO mail dated 20.05.2020 & 07.07.2020 & 11.11.2020:


configured

2.COMPLIED


4.out of 30 CTs, 27 No CTs have been replaced with new one. Time line requested upto 31.12.2020

82/I/1 Sl No. 3 Pending28-01-2019

at 01:15 Hrs


Sriperumbudur stationTANTRANSCO

1) TANTRANSCO to ensure proper legends for DR Digital signals and all required

events(including CB status, Type of protection operated) are captured in Event logger.

2) TANTRANSCO to extend BBP trip from BusBar relay to 86A (with source-1 DC) in

addition to 86B (with source-2 DC), or to provide Common trip relay 96 with redundant DC

supply.

3) TANTRANSCO to inform the action plan with timelines for providing Numerical BBP at

Sriperumbdur SS .

4) TANTRANSCO to check the healthiness of all CT’s in the stationand submit a report

regarding the same to SRPC to prevent any such occurrence in future.

Failure of ‘R-phase’ HV side Current transformer (CT) of

315MVA 400/230kV ICT-3 at 400kV Sriperumbudur

substation (400kV TANTRANSCO switchyard).

Annexure-C

Page 43 of 52

TANTRANSCO maiil dated 18.01.2021:

1. At present Duobias relay avaiable I/O configuration could not be carried out. New relay allotted and awaiting for line clear . Time

line requested upto 31.03.2021.

2.COMPLIED


4.out of 30 CTs, 29 No CTs have been replaced with new one. One no of CT is kept pending due to oil leak.Time line requested upto

31.03.2021.

TANTRANSCO mail dated 28.04.2021, 28.05.2021:

1. At present Duobias relay avaiable I/O configuration could not be carried out. New relay allotted and awaiting for line clear . Time

line requested upto 31.12.2021.

2.COMPLIED


4.out of 30 CTs, 29 No CTs have been replaced with new one. One no of CT is kept pending due to oil leak.Awaiting OEM for

rectification.Time line requested upto 31.12.2021.


1. Complied.

2. Complied.


4.1 No CT pending to be erected . Oil leak attended by OEM.

TANTRANSCO Mail dated 28.12.2021

3.BBP received. Work to be taken up.

85/II/1Tripping of 400/230kV

MANALI ICT-313-05-2019 at 2:42 hrs

ICT-3 got tripped on the activation of HV REF protection.

During test charging of 110 kV Manali-ETPS -1 , the 110 kV

ETPS -1 got tripped on the activation of Back up relay and

Distance relay failed to act

1. TANTRANCO is recommended to sort out the malfunctioning of ICT Ref protection in

consultation with OEM and submit a detailed report regarding the same in 1 month time.

2. TANTRANSCO is recommended to ensure proper labelling of all digital signals in

Disturbance recorders of lines and ICTs at Manali SS.

TANTRANSCO


1. The issue was addressed to OEM reply awaited.

2. Uniform Labelling of Digital signal will be ensured.



2. Proper labeling of D.R has been implemented.

TANTRANSCO mail dated 20.05.2020 & 07.07.2020 & 28.09.2020 & 11.11.2020 & 18.01.2021, 28.04.201 28.05.2021:


2. Complied

TANTRANSCO mail dated 17.07.2021:,06-10-2021, 28.12.2021

reply awaited from OEM

reply awaited from OEM

89/II/2Tripping of 400/230 kV ICT-2

at Sungavarchatram SS of

TANTRANSCO

28-11-2019 at 10:43

Hr.

• 400 kV SVC SS-ICT2- R phase tripped on percentage

Differential & REF protection.

• During test charging of 110 KV Oragdam-SP Koil-1# at 230

KV Oragadam SS the feeder got tripped on SOTF due to R

phase CT blast.

i. TANTRANSCO to test all CTs (secondary voltage measurement and Tandelta

measurement) and replace if CTs found mal-operating. CT cable also needs to be tested.

ii. TANTRANSCO to furnish the OEM findings regarding the tripping at the earliest .TANTRANSCO


will be complied

TANTRANSCO mail dated 14.07.2020 & 28.09.2020 & 11.11.2020 & 18.01.2021:

OEM has reported that the misbehave of LVCT at ICT2 leads tripping. Action is being taken to replace the same. Timeline

requested upto 31.12.2020


OEM has reported that the misbehaviour of LVCT at ICT2 leads to tripping. Action is being taken to replace the same.Time Line

requested upto 31.07.2021


Action is being taken to replace the same.Time Line requested upto 31.12.2021.


CT allotment awaited. For replacement. Time Line requested upto 30.06.2022

Pending

91/I/5

Complete outage of

230kV/110kV Karambyam SS

and Multiple Tripping in

230kV/110kV Thiruvarur SS

of TANTRANSCO

19-04-2020 at

04:14Hrs

• Triggering incident was YN fault in 230kV Karaikudi-

Karambyam line.

• At the same time, bus fault occurred at 230kV Thiruvarur

SS due to snapping of B phase dropper conductor of 230 kV

Thanjavur-Thiruvarur line near Bus-1 side isolator and Bus-1

BBP operated resulting in the tripping of all the elements

connected to 230kV Thiruvarur SS.

• Since 230kV Thiruvarur SS was under single bus operation,

this resulted in de-energization of 230kV bus at Thiruvarur

SS.

• Tripping of 230kV Karaikudi-Karambyam line and 230kV

Thiruvarur-Karambyam line resulted in complete loss of

supply at 230kV Karambyam SS.

i. TANTRANSCO to avoid single bus operation at their Substations where atleast 2 buses

are available.

ii. To share the reasons for SLDC instruction for single bus operation at Tiruvarur.TANTRANSCO

TANTRANSCO vide mail dated 28.09.2020 & 11.11.2020:

Due to Isolator feed back problem, the single bus operation has been maintained


Due to Isolator feed back problem, the single bus operation has been maintained. Action is being taken to implememt the double bus

operation Time line requested upto 30.06.2021



operation. Time line requested upto 31.12.2021



operation.


Pending

92/1/IComplete outage of 230kV

Mywadi substation of

TANTRANSCO

22-06-2020 at 23:47

Hr.

• During antecedent conditions, 230kV Mwyadi SS was under

single bus operation.

• Triggering incident was failure of B phase CT of 230kV

Mywadi-Ponnapuram line-2 at 230kV Mywadi end.

• 230 kV Bus-1 bus bar protection operated resulting in the

tripping of all the connected elements at 230kV Mywadi.

• 400kV/230kV Udumalpet ICT-1, 2 and 3 also tripped during

the event.

i. TANTRANSCO to expedite the process of Bus strengthening at 230kV Mywadi SS, on

priority , in order to restore double bus operation. Healthiness of other CTs in the SS shall

also be ensured.

ii. TANTRANSCO requested to submit equipment failure report to CEA with a copy to

SRPC.

TANTRANSCO


1. Busbar protection with Zone segregation work have been completed . Double bus operation can be done after strengthening of

bus (Twin Moose to Quad Moose). Time line requested upto 31.12.2020

2.


Strengthening of bus (Twin Moose to Quad Moose) programmed on 24.01.2021 Time line requested upto 31.01.2021. for

implementation of double bus operation





completed in ICT.1 ( bus isolator) & awaited Line clear for executing the work. Time line requested upto 31.12.2021.

TANTRANSCO: Mail dated 28.12.2021


completed in ICT.1 ( bus isolator) & awaited Line clear for executing the work. Time line requested upto 30.06.2022.

Pending

82/I/1 Sl No. 3 Pending28-01-2019

at 01:15 Hrs


Sriperumbudur stationTANTRANSCO

1) TANTRANSCO to ensure proper legends for DR Digital signals and all required

events(including CB status, Type of protection operated) are captured in Event logger.

2) TANTRANSCO to extend BBP trip from BusBar relay to 86A (with source-1 DC) in

addition to 86B (with source-2 DC), or to provide Common trip relay 96 with redundant DC

supply.

3) TANTRANSCO to inform the action plan with timelines for providing Numerical BBP at

Sriperumbdur SS .

4) TANTRANSCO to check the healthiness of all CT’s in the stationand submit a report

regarding the same to SRPC to prevent any such occurrence in future.

Failure of ‘R-phase’ HV side Current transformer (CT) of

315MVA 400/230kV ICT-3 at 400kV Sriperumbudur

substation (400kV TANTRANSCO switchyard).

Annexure-C

Page 44 of 52

94/II/13Tripping of 400/230kV ICT#2

at Tiruvalam

01-Nov-20

10:57 hrs

01-Nov-20

12:17 hrs

02-Nov-20

11:32 hrs

25-Nov-20

21:26 hrs

ICT#2 and 400kV Alamathy -Thiruvalam line-2 are in the

same dia at 400kV Thiruvalam end. During antecedent

conditions, Main breaker of ICT#2 at Thiruvalam end was

under outage due to CT replacement works. Triggering

incident was R phase to Earth fault in 400kV Alamathy -

Thiruvalam line-2. A/r operated successfully at both the ends

and line was holding. At Thiruvalam end, A/R of main breaker

only operated and tie breaker tripped. Due to tripping of tie

breaker at Thiruvalm end, ICT#2 also tripped

i. TANTRANSCO to enable A/R for both Main-CB & Tie-CB in all dias where one of the

elements is a transmission line at their 400/ 230 kV Thiruvalam SS.

ii. TANTRANSCO to configure OVR start and OVR trip in DR/ EL of the protection relays of

all 400kV transmission lines emanating from their 400/ 230 kV Thiruvalam SS

TANTRANSCO


Will be ensured after getting concurrence from our R&D wing,


TANTRANSCO R&D wing suggested to get clearence from OEM.


addressed to OEM and reply awaited.

TANTRANSCO mail dated 06-10.2021:

M/s.CG POWER AND INDUSTRIAL SOLUTIONS ( OEM) replied that on two phase condition on ICT/AUTO Tr for minimum of

1.5 sec till auto reclosure / Lockout for each feeder fault, which results in prolonged over voltages in the system and across

Transformer. If this condition persist for longer frequencies which could deteriorate the transformer insulation due to over voltage

transients.The above operating condition is not suitable from transformer perspective and we donot recommend this condition.

Pending


400/230 kV Alamathy SS of

TANTRANSCO

19-02-21

23:49 hrs.

Triggering incident was Y-E fault in the 400kV Alamathy -

NCTPS ST2 line-1. At Alamathy end, fault was sensed in

Zone-1. At NCTPS ST2 end, carrier aided Zone-2 protection

operated. A/R operated and line tripped on persistent fault at

both the ends. At the same time, at Alamathy end, BBP Zone-

1 protection operated at 400 kV Bus-1 and all the elements

connected to 400 kV Bus-1 got tripped. 400/230 kV ICT#3 at

Alamathy also got tripped during this event since Tie C.B was

under LC for new reactor commissioning work during

antecedent.

TANTRANSCO to expedite the process of providing numerical BBP at their 400/ 230kV

Alamathy SS.TANTRANSCO

TANTRANSCO mail dated 28.04.2021, 28.05.2021 & 17.07.2021:,06-10-2021

Numerical relay procurement under progress.



Pending

Annexure-C

Page 45 of 52

99/I/A/13

Complete Outage of

230kV/110kV Karaikal SS of

Pondicherry

29-10-2021

09:39 hrs

As per the report submitted, triggering incident was R-Y-N

fault in 230kV Neyveli-Karaikal and 230kV Bahoor-Karaikal

lines. Both the lines got tripped and this resulted in

complete outage of 230/110 kV Karaikal SS.

PED to consult OEM to sort out the following issues and submit a report regarding the

same:

(i) The difference in fault distance computed by Main relays at Karaikal end of 230kV

Karaikal - Bahour line.

(ii) Sensing of R-Y-E fault as R-E fault at Karaikal end of 230kV Karaikal - Bahour line, even

though Iy was observed to be greater than Ir.

(iii) Tripping of 230kV Karaikal – NLC TS-II line at Karaikal end while A/R was in progress

due to receipt of carrier signal from NLC end.

PED Status received vide PED mail dated 30.01.2022:

230/110KV Karaikal Auto SS was erected and commissioned by PGCIL for Puducherry Electricity Department. Any trouble arising

from this station is being attended with the coordination of PGCIL since the commissioning of this station during the year 2019.

As such, coordination of PGCIl has been requested vide Lr. No.879/ED/EE-EHV/AEE-EHV/F-PGCIL/2021-22, dated 27.01.2022 for

the implementation of SRPC recommendations. Once the recommendations are implemented, a report will be furnished

immediately. Pending

Multiple trippings at 220 kV

Madakathra station

Status received vide mail dated 11-12-2018:

In progress


Status as on 18.03.2019: Estimate sanctioned by CE(Transmission North ) and have prepared the technical specifications.Tendering

procedures are yet to get started.


At the time of bid only one bidder participitated and the work has been retendered.


Retendering process in progress. Time Frame is January 2020 .

Review meeting on 27.06.2019.

work has been awarded

KSEBL mail dated 16.12.2019:

Drawing varification is under progress.Work will be completed by the end of March 2020


MDCC issued for 220 kV BBP Panel to M/s N/R Energy India Ltd. Panel not yet arrived at site.Expecting Panel on or before

25.07.20

Additional Cable laying works in switch yard - 95% completed.

The Bus Bar Protection is expected to be in serrvice on or before 25.09.2020


Work completed . Testing is going on.


Commissioning work is almost completed andit is under observation-----Pending


Numerical Busbar protection put in service during September 2021


The work completed in September 2021----Completed

The work is in progress along with the

replacement of 22kv Control Panels.

Scheduled to be completed by 31.12.2021


Bhramapuram substation of

KSEB

08-02-2019 at 10:28

hrs

Complete outage of 220kV Brahmapuram SS occurred due to

suspected mal operation of Bus Bar protection.

1) KSEBL to furnish detailed report regarding the healthiness of BBP operation at 220kV

Brahmapuram after testing of the same on 12th April 2019.

2) KSEBL to submit the action plan regarding

(i) Replacing of the Static High impedance BBP (using CRM relays) with Numerical BBP.

(ii) Replacement of CRM relays and relays with no Disturbance recording facilitites.

KSEBL

Status received vide mail dated 03.05.2019 & 11.202.2020:

1) Detailed report sent on 02.05.2019…..Completed.

2) As reported earlier in this regard, the permanent solution to this problem is to replace the existing high impedance static relay with

a low impedance numerical relay. The station authorities have already initiated action to implement the same by June 2020.


The work is included in 220kVSAS integration.The work is tendered .To be completed on 31.12.2020.

KSEBL mail date 23.04.2021:

Work will be completed on 31.08.2021.


The work is in progress along with the replacement of 22kv Control Panels. Scheduled to be completed by 31.12.2021


The work is in progress along with the replacement of 220kv Control Panels. Scheduled to be completed by 20.02.2022.

Pending

Kerala

PED

CompliedKSEBLKSEBL to take steps to replace the existing static (high impedance type) 220 kV BBP with

numerical Busbar protection at their 220 kV Madakathara SS.

Triggering incident was Y-phase to ground fault in 220kV

Madakathra – Palakkad_KL (Ellapully) line due to flashover

of pilot insulator string. Auto-reclose was successful at

Madakathra end. At the same time bus differential relay Zone-

C mal-operated resulting in tripping of all elements connected

to the bus.

15-10-2018 at 08:57

Hrs80/II/5

Annexure-C

Page 46 of 52


Edamon SS of KSEB

27-05-2019 at 12:30

hr.

Triggering incident was three phase to earth fault in 220 kV

Edamon Bus 1 and 2. Bus 1 and 2 Bus bar protection operated

resulting in the tripping of all connected elements.

1.KSEBL may develop proper operational code for procedures to be followed while

performing operations in switchyard and sensitize their operators to reduce operational

errors. 2.ksEBL to ensure time synchronization of relays at 220 kV Edamon SS.

KSEBL


1. proper operrational code is avilalable in 220kV SS Edamon

2. All 220KV relays of Edamon substation are synchronized with GPS clock . Out of this, 3 relays are having hardware issues with

time synchronisation switch . This problem will be resolved by August 2019 itself.

KSEBL mail dated 28.08.2019

2. By August 2019, could rectify the hardware issue with 2 relays. Other will be done by September 2019.


Have taken steps to rectify the hardware issue with the 3rd relay and will be completed by end of December 2019


Have taken steps to rectify the hardware issue with the 3rd relay and will be completed by end of March 2020


Have taken steps to rectify the hardware issue with the 3rd relay and will be completed by end of April 2020


The harware issues related to the third relay were rectified in December 2021…Completed

Complied


Have taken steps to rectify the hardware issue with the 3rd relay and will be completed by end of October 2020.


Have taken steps to rectify the hardware issue with the 3rd relay and will be completed by end of August 2021

89/1/5

Complete loss of supply at 220

kV Kanhirode, 220 kV

Ambalathara, 220 kV Mylatty,

220 kV Thaliparamba and 220

kV Orkattery SS of KSEB

08-01-2020 at 14:22

Hr.

• Triggering incident was conductor snapping of 220 kV

Kanhirode – Ambalathara feeder.

• Bus bar protection at 220 kV Kanhirode SS operated

resulting in tripping of all connected elements.

• There was complete loss of supply at 220 kV Ambalathara,

Mylatty, Thaliparamba and Orkattery SS of KSEB since these

station were radially fed from 220 kV Kanhirode station.

KSEBL to replace existing high impedance BBP and mal-operating check Zone relay with

Low impedance BBP at 220kV Kanhirode SS.KSEBL


Work will be completed by the end of December 2020



KSEBL Mail dated 19.11.2021:

Tendering of 220kV low impedance BBP to Kanhirode and Mylatty 220 kv ss will be done by this week.

KSEBL Mail dated 05.02.2022.

Some clarification sought from the lowest bidder participated in tender and PO will be issued soon.

Pending

89/II/1Tripping of Bus-1 and Bus-2 at

220 kV Brahmapuram station

of KSEB

26-11-2019 at 09:04

Hr.

• Bus bar protection of Bus-1 operated resulting in tripping of

all elements connected to Bus-1 at 220 kV Brahmapuram.

KSEBL to expedite the process of providing numerical BBP in place of mal-operating CRM

relays at 220 kV Brahmapuram SS.KSEBL




The work is included in 220kVSAS integration.The work is tendered .To be completed on 31.12.20


Work will be completed on 31.08.2021

KSEBL mail dated 19.112021:

The work is in progress along with the replacement of 22kv Control Panels. Scheduled to be completed by 31.12.2021.


The work is in progress along with the replacement of 220kv Control Panels. Scheduled to be completed by 20.02.2022

Complied

91/I/3


Kattakada SS and Multiple

Tripping in 220kV Pothencode

SS of KSEB

14-04-2020 at

10:32Hrs

• Triggering incident was RN fault in 220kV switchyard of

Kattakada SS.

• Both 220kV Pothencode-Kattakada line-1 & 2 tripped.

• At the same time, 220kV/110kV 200MVA transformers 1, 2

and 3 at Pothencode and 220kV/110kV 200MVA

transformer# 1 at Kattakada also got tripped.

• Tripping of 220kV Pothencode-Kattakada line-1 & 2

resulted in complete loss of supply at 220kV Kattakada SS

since it is radially fed from Pothencode SS.

i. KSEBL to expedite the process of providing BBP and GPS time synchronization of relays

at 220kV Kattakada SS at an early date.

ii. DRs at Pothencode & Kattakada to be configured for all zone pick up and blocking of

DEF on distance pick up to be ensured at Pothencode SS relays.

KSEBL


1)BBP Work will be completed by end of March 2021---- Pending

GPS time synchronization issue resolved at 220kV SS Kattakada--Completed

2) DRs at Pothencode & Kattakada configured for all zone pick up-- Completed

KSEBL vide mail dated 11.09.2020 informed that:

i. Pending

ii. DEF at Katakada is configured in external relay and time delay is set as back up to 2nd zone of protected line and hence possibility

of maloperation is very less. It will not act before distance protection.


i) Work retenderd.Work will be completed on 31.12.2021


Work to be retendered again with review specifications. Expected to be completed by March 2022.

Pending


Sabarigiri GS of KSEB

01-Oct-20

18:06 hrs

Triggering incident was failure of R-phase CT connected to

220kV Sabaigiri - Edamon feeder-2. As reported LBB

operated and all connected elements tripped at Sabarigiri end

only resulting in complete outage of 220kV Sabarigiri station.

i. KSEBL to submit Equipment failure report for the failed CT to CEA with a copy to

SRPC.

ii. KSEBL to revise LBB timings for all feeders at 220kV Sabarigiri GS to 200msec

(existing 250msec) and configure LBB operation for sending of DT to remote end.

iii.End zone protection shall also be configured for all 220 kV lines at their 220 kV

Sabarigiri GS.

KSEBL


1)Equipment Failure Report mailed on 09.03.2021.......Completed.

ii) LBB timings revised for all feeders at 220kV Sabarigiri GS to 200msec-----pending

iii)End zone protection configured for all 220 kV lines at 220 kV Sabarigiri GS .....Completed


ii)LBB time of all the bays revised and the new time is 200msec.

KSEBL Mail dated 05.02.2022:

ii)Configure LBB operation for sending of DT to remote end-- pending

Pending (ii)

PGCIL

(SR-I &

II)

Annexure-C

Page 47 of 52

90/I/4


Kolar, 220kVMalur, 220kV

Sarjapur and 220kV VTP SS of

KPTCL

09-05-2020 at

22:41Hr.

During antecedent conditions, 220kV Kolar(Kar), 220kV

Malur, 220kV Sarjapur and 220kV VikasTech Park (VTP) SS

are radially fed from 220kV Kolar PG SS. Triggering incident

was YB fault in220kV Kolar PG- Kolar(Kar) line-1. After

tripping of 220kV Kolar PG-Kolar(Kar) line-1, 220kV Kolar

PG-Kolar(Kar) line-2 got overloaded and tripped at

Kolar(Kar) end due to operation of non-directional OC

protection. Due to tripping of 220kV Kolar(PG)-Kolar(Kar)

line-1 and 2, there was complete loss of supply at220kV

Kolar(Kar), 220kV Malur, 220kV Sarjapur and 220kV Vikas

Tech Park (VTP) SS

PGCIL-SR-2 to submit justification regarding adopting Zone-2 timing of 100msec and Zone-

3 timing of 200msec on 220kV Kolar_PG Kolar_KA line.PGCIL-SR-II

PGCIL mail dated 02.07.2021:, 04-10-2021

Any prolonged fault in the 220 KV system is effecting the HVDC operation issue needs to be delibrated in SRPC forum.Pending

Others

Response from MAPS Latest Status The AR

scheme is implemented in 230 kV SPKoil-1

line. The performance will be observed

during line transients and based on the

satisfactory results it is proposed to

implement in other three lines

Annexure-C

Page 48 of 52

NPCIL(MAPS) email dated 01.09.2020:

Necessary approvals were taken for the scheme from station management for implementing the AR for all the 230kV lines. The AR

will be implemented before 31-10-2020.

NPCIL (MAPS) email dated 02.11.2020:

The Auto Reclose (AR) scheme is being tested at Relay Testing lab. The AR will be implemented, for all the 230kV lines of MAPS,

before 31-12-2020.

NPCIL (MAPS) email dated December 2020:

The Auto Reclose (AR) scheme is tested at Relay Testing lab. The test results are being reviewed by NPCIL, HQs. The AR will be

implemented, for all the 230kV lines of MAPS, before 31-03-2021. This is for your information.


TPCIL station

25-10-2017 at 19:33

hrs

400 kV TPCIL-Nellore PS line-1 got tripped from TPCIL end

during fault in 400kV Nellore-Nellore PS line-2. Running units

at TPCIL got tripped due to loss of evacuating line. 400kV

Nellore PG - Nellore PS line-2 and 400kV TPCIL - Nellore

PS line-1 were under shutdown.

TPCIL to configure DEF protection such that it remains in blocked condition as long as

Distance Protection is active, and becomes active only when distance protection does not

pickup.

TPCIL


It was noted that no TPCIL representatives had come to attend the meeting

Review meetinmg on 27.06.2019:

No representative from the utility attended meeting and it is requested to submit status regrading the recommendation at athe earliest.

Pending

Response from MAPS Latest Status The AR

scheme is implemented in 230 kV SPKoil-1

line. The performance will be observed

during line transients and based on the

satisfactory results it is proposed to

implement in other three lines

02-04-2016 at 17:08

hrs


S.P.Koil Station of

TANTRANSCO

54/I/1

Status revided vide MAPS mail dated 06.12.2016;

1. The settings given by M/s TANTRANSCO were adopted for Main –I & Main- II relays for both the lines. The same settings were

verified to be same. Subsequently calibrated was done and no drift was observed. --- Completed

2. From May 2016 onwards, the DR, EL and trip report are being sent by mail to SRLDC, Bengaluru by MAPS. --- Completed

3. Monthly maintenance of PLCC equipments is being done by M/s TANTRANSCO. At present PLCC telephone is not working, it is

being followed up. --- Completed

4. CVTs are planned to be procured from M/s TANTRANSCO by the end of February 2017 and A/R will be implemented for all the

lines emanating from MAPS by July-2017 as discussed in the current SRPC meeting on 25/11/2016. --- Pending

Status received vide MAPS mail dated 06.12.2016 & Review Meeting dated 19.12.2017;

The CVTs procurement is in progress and the scheme (A/R) would be implemented before 31-03-2018.

Status revided vide MAPS mail dated 11.12.2018

The new CVTs were provided in all the three phases (R & B phases, CVTs were replaced and Y ph CVT was provided) of Line-1,2

& 4. Replacement of CVTs in line-3 is in progress. Each phase CVT supply was extended to Main 1 & Main -2 relays. Bus PT

supply is extended for Sync.Check.

Time Delayed Auto Reclose (TDAR) scheme with Sync. Check, is being worked out and will be implemented for the four lines, on

by one, before 31-03-2019.



NPCIL (MAPS) mail dated 30.10.2019:

The validation of the PSL logics in the spare relay is in progress. Hence Auto reclose will be implemented by 30th November 2019.


Response from MAPS Latest Status The AR scheme is implemented in 230 kV SPKoil-1 line. The performance will be observed

during line transients and based on the satisfactory results it is proposed to implement in other three lines

PendingNPCIL (MAPS)

1.MAPS to furnish a detailed report on the tripping of SP Koil – MAPS lines 1 & 2 at

MAPS end with focus on the correctness of the settings of Main-I & Main-II relays (for

primary & back-up protections) on both the lines.

2.MAPS to take steps to provide down-loading facility for DR & EL from Main-I & Main-II

relays on all 230 kV lines emanating from MAPS.

3.MAPS, in co-ordination with SP Koil, to carry out PLCC end-to-end testing, on SP Koil –

MAPS lines 1 & 2, and ensure healthiness of PLCC communication & carrier-aided

protection.

4.MAPS to put in service Auto-Reclosure feature on all four 230 kV lines emanating from

MAPS by June, 2016.

B-phase CT failure occurred in 230 kV S.P.Koil - MAPS line-

1. Busbar protection got operated at SP.Koil station. All

elements except 230kV Oragadam and 230kV Kalivandapattu

got tripped at 230kV S.P.Koil station. ‘Y’ phase CT and

support insulators also got damaged.

Annexure-C

Page 49 of 52

78/II/2Tripping of 400 kV Neyveli

TS2Exp -Pugalur line

01-08-2018

at 11:56 hrs

Triggering incident was failure of R-ph tension insulator

string/ flashover in 400 kV Bus-1 at NLC TS2Exp end.

Busbar protection had operated resulting in tripping of all

main breakers connected to 400kV Bus-1 at Neyveli TS2 Exp.

In 400kV NLC TS2Exp - Pugalur line, fault was sensed in

Zone-1, R-N at Pugalur end resulting in a single phase trip.

Direct Trip was received at Pugalur end due to operation of

over voltage Stg-2 at NLC TS2Exp.

1. NLCIL to furnish a report along with a suitable SLD on the tripping event explaining the

observed discrepancies [DPR, Z1 operation, instantaneous operation of OVR-II operation],

and remedial action taken to attend the same.

2. NLCIL to configure DR’s & EL’s of all protection relays at their NLC TS-IIExp station

for all mandated protections & signals.

NLCIL


NLCIL was asked to furnish the status of implementation of the recommendation given at the earliest.



Pending

79/II/8Tripping of 400 kV NLC TS-2

(Exp) – Pugalur line

10-09-2018 at 20:57

hrs

Line tripped on B-N fault. Auto-reclose was not attempted at

Pugalur end due to DT receipt from NLC TS2Exp end. At

NLC TS2Exp end, V>2 trip was observed in DR. Analog

voltages recorded in DR were observed to be less than that

required for O/V Stage-II operation.

NLCIL to furnish a detailed report on tripping event explaining the observed discrepancies ,

and proper reasons for tripping of the line considering both the Main-relays including

remedial action taken w.r.t. healthiness/ replacement of Main protection relays on 400 kV

NLC TS2Exp–Pugalur line.

NLCIL


NLCIL was asked to furnish the status of implementation of the recommendation given at the earliest.


it is requested to submit status regrading the recommendation at athe earliest.

Pending

80/II/17Tripping of 400 kV Nellore PS

– SGPL line-1

14-11-2018 at 20:20

hrs

Y- ph to earth fault occurred in line due to snapping of GIS to

Air bushing conductor at SGPL switchyard. The conductor

got grounded such that the fault was being fed by NPS bus

and there was earth fault and broken conductor start at SGPL

end. NPS end got tripped in Zone-2 due to non-receipt of

carrier resulting in a 3-ph trip at NPS. After 500ms, earth fault

occurred at SGPL end resulting in Zone-1 operation and 3

phase trip. A/R was not attempted at SGPL end

SGPL to examine the reasons for no-operation / failure of Auto-reclosure from their end for

the subject tripping, and furnish an action taken report detailing remedial measures taken to

PCSC forum.

SGPLReview meetinmg on 27.06.2019:

No representative from the utility attended meeting and it is requested to submit status regrading the recommendation at athe earliest.Pending

80/III/6Tripping of 400 kV Neyvelli

TS2 (Exp) - Pugalur line

07-11-2018 at 05:50

Hrs

400 kV Neyvelli TS2Exp - Pugalur tripped on

B-phase to ground fault due to DPR, Z1 operation. Auto-

reclose was successful at Pugalur end and the line tripped at

Neyveli TS2Exp end only. Auto-reclose was not attempted at

Neyveli TS-2(Exp) end

NLCIL to furnish a detailed report on the reasons for A/R non-operation for the subject

tripping at their NLCTS2Exp station including remedial measures taken to PCSC forum. NLCIL


No representative from the utility attended meeting and it is requested to submit status regrading the recommendation at athe earliest.Pending


NLC1 Expansion(NLC1EXP) 05-06-2019at 18:51 hr. Triggering incident was failure of Y-phase CT of GT-1 (Generator Transformer) at 400kV NLC1EXP. Bus-1 Bus bar protection operated resulting in the tripping of NLC1EXP U#1 and 400kV NLC1EXP- Nagapattinam line

1. NLCIL to check the healthiness of R & B ph CT of Unit-1 at NLC TS1(Exp) and if

found unhealthy replace the same alongwith replacement of Y-ph CT. CT replacement plan

and timeframe shall be informed to SRPC.

2.NLCIL in coordination with PGCIL(SR-II) to resolve the time syncronisation issues in

230kV NLC TS1(Exp) – Nagapattinam line.

3. NLCIL was also requested to investigate the reason of unwarranted DT sent to NLC TS1

(Exp) end from NLC TS2 end and resolve the same.

NLCIL

NLCIL mail dated 09.07.2019:

AT TS2 Side Siemens 7SA52 & Micromho relay are used for distance protection. During the incident Micromho has sensed the CT

blast as a Zone-1 fault and tripped the feeder. Adt signal was send to TS1 Exp end. The relay will be tested during the next shut

down.

NLCIL mail dated 11.01.2020:

3. Michro mho Relay Testing was carried out at TS2 end on 15/11/19 and found the relay was normal.Proposal has already been

initiated to replace distance relays with line differential relays. It is also proposed to replace the PLCC panels at both ends. --

Completed

Pending

85/II/19Tripping of 400kV JSW-Guttur

line

02-06-2019 at 18:17

hrs

Line tripped due to OV St-1 protection operation at JSW end

and DT was sent to Guttur end. At Guttur end B ph voltage

was observed to be lesser comparing to R ph and Y ph(Vr-

249kV, Vy-255kV and Vb-230kV).

JSWEL is recommended to monitor the B-ph CVT of 400kV JSWEL-Guttur line (due to

lower B-ph voltage compared to other two phases). The same shall be replaced if the issue

persists.

JSWEL Yet to be informed Pending

85/II/21Tripping of 400kV JSW -

Guttur line and 400 kV Kaiga -

Guttur line-2

05-06-2019 at 18:27

hrs

Y-phase to earth fault occurred in 400kV Kaiga-Guttur line-2.

A/r was successful at Guttur end. At Kaiga end A/r was not

attempted and breakers got tripped due to operation of Pole

discrepancy (1.65 Sec). 400kV JSW-Guttur line tripped on

operation of over-voltage at Guttur and direct trip was

received at JSW. From DR of Guttur, it is observed that there

was swell in R & Y phase voltage for few cycles

1. NPCIL (KGS) is recommended to identify the issue related to unsuccessful A/R attempt

of 400kV Kaiga – Guttur line and non-opening of R-pole CB. It is recommended to check

the healthiness of all breakers including breaker timing.

2. Time synchronization of DR and EL at Kaiga end shall be ensured.

NPCIL (KGS)

NPCIL mail dated 13.12.2019:

During the event Distance Protection Main-2 detected Y-ph fault and opened the Y-ph pole and initiated A/R to process.

subsequent to that IN> started for B-ph. Actuation of IN> during the dead time leads to A/R lockout. So pole discrepancy operated at

kaiga end as per the scheme.

DR and EL are already GPS synched at Kaiga end.


Event is forwarded for Designer review


Event was reviewed by Designer.Consulted OEM and Recomendation of OEM implemented to resolve the problem.

85/IV/7Tripping of 400kV Ramadugu-

Singareni line

11-06-2019 at 08:24

hrsLine tripped due to Direct Trip receive at Ramadugu end

Singareni STPP is recommended to submit a detailed report regarding sending of DT from

singareni end that resulted in tripping of 400kV Ramadugu-Singareni line.Singareni TPP Yet to be informed Pending

86/III/2 Tripping of Kaiga-Gutur line -2 22-07-2019 at 17:47hr.Line tripped on B-phase to earth fault. Line did not auto-

reclose. NPCIL (KGS) to ensure time sync between DR and EL at Kaiga end. NPCIL


DR and EL are already GPS synched at Kaiga end.

During the event Auto reclose was successful from KGS end. Due to existence of fault on B-phase, within 9 mili sec of closure, line

CB-2B again tripped. As per information from Guttur end, insulator flash over took place at tower No:103.


DR and EL are already GPS synched at Kaiga end

Annexure-C

Page 50 of 52

87/III/4Tripping of 400 kV Kaiga-

Narendra line-206-09-2019 at 4:33 hr.

Line tripped on Zone-1 distance protection operation due to R-

phase to Y phase fault. At Kaiga end line auto-reclosed.

NPCIL (KGS) to review A/R scheme at Kaiga GS. As per A/R logic, any phase to earth

fault detection should lead to opening of the faulted phase and reclosing after dead time. But

during dead time if any subsequent fault occurs it should block A/R and 3-ph trip should be

extended.

NLCIL (KGS)


Distance protection of Main-2 detected R-ph fault and opened the R-ph pole, initiated A/R to process.Subsequent to that Y-ph fault

detected by Main-1 distance protection within 71 m.sec of Rph fault and opened the Yph-pole.

Since Y-pole opened within the dead time and main-2 relay extended the close command to both the pole after laps of dead time as

per scheme


Distance protection of Main-2 detected R-ph fault and opened the R-ph pole, initiated A/R to process.Subsequent to that Y-ph fault

detected by Main-1 distance protection within 71 m.sec of Rph fault and opened the Yph-pole.

Since Y-pole opened within the dead time and main-2 relay extended the close command to both the pole after laps of dead time as

per scheme

88/III/7Tripping of 400kV NLC TS-2

Exp- Pugalur line

29-10-2019 at 16:43

hr.

Triggering incident was Y phase to Earth fault in the line. At

Pugalur end, fault was detected in Zone-1 and A/R operated

successfully. At Neyveli TS-2 Exp end, fault was detected in

Zone-1 and A/R not operated.

NLCIL to submit a detailed report regarding the reason for failure of A/R in consultation

with OEM.NLCIL Yet to be informed Pending


Ramagundam - Malkaram

07-03-2020 at 04:38

Hr.

Triggering incident was Y N fault in the line. At Ramagundam

end, fault was sensed in Zone-1, A/r operated and line tripped

due to persistent fault. As per the report submitted at

Malkaram end, it was mentioned that line was in service; the

same needs review.

As per the report submitted by Ramagundam it was mentioned

that, analog module of relay maloperates intermittently and

the same needs review.

NTPC (Rmgdm) to sort out the issue regarding maloperation of Main-1 relay and send a

report after replacement of the same. DR and EL at Ramagundam end for the subject line

also need to be time synchronized

NTPC(RMGDM) Yet to be informed Pending

90/II/21Tripping of 400kV Vallur –

NCTPS line-1

19-Mar-2020 at 12:05

Hr.

Shutdown for 400kV Vallur- NCTPS line-1 was planned from

09 hr. -1700 hr. on 19.03.2020. While closing NCTPS line 1

Earth switch at NTECL end, heavy voltage dip was

experienced and all the three running units of Vallur tripped

on Low Forward Power Protection at 12:05 hr. Earth switch

of the line was closed at Vallur end without opening of remote

end breaker, which resulted in three phase to ground fault in

400kV Vallur - NCTPS line-1 at Vallur end. Gen Loss: 1893

MW.

i. NTECL-Vallur to ensure proper communication regarding remote end isolation before

closing of earth switch in their switchyard to prevent recurrence of such faults in future.

ii. NTECL-Vallur, in coordination with TANGEDCO, to restore communication channel

between the NTECL-Vallur and NCTPS and submit a report to SRPC regarding healthiness

of the same.

NTECL-Vallur Yet to be informed Pending

90/IV /3Tripping of 400kV Neyvelli 2

(Exp) - Pugalur line

30-03-2020 at

15:10Hr.

Triggering incident was Y-phase to ground fault in the line.

Line tripped on Zone-1 distance protection.Auto reclose

attempted but locked out due to persistent fault. At Pugalur

end, DT was received resulting in 3phase trip.

DT sent from Neyvelli end needs review.

NLCIL to submit a detailed report regarding A/R non-operation and sending of DT at

Neyvelli 2 (Exp) end for the subject line. NLCIL Yet to be informed Pending

91/III/3

Tripping of 400kV

JSW-

Guttur line

07-04-2020

at 16:10Hrs

• Triggering incident was B –N fault in the line.

• At JSW end, line tripped on operation of Z1 distance

protection and A/r not operated.

• At Guttur end, A/r operated successfully and line tripped due

to subsequent fault during reclaim time.

JSWEL to furnish detailed report regarding A/R non-operation at their end for the subject

line and the remedial measures taken for the same.JSWEL Yet to be informed Pending

91/IV/1Tripping of 400kV

Ramagundam Dichipally line

18-04-2020

at 13:10Hrs

16-05-2020

at 12:25Hrs

Line tripped only at Ramagundam end on DT receive.

Suspected PLCC maloperation.

Line tripped only at Dichipalli end on DT Receive due to

suspected maloperation of PLCC during PLCC checking by

TSTRANSCO at both the ends .

NTPC (Rmgdm) to submit a report regarding DC leakage in their switchyard and

healthiness of PLCC channel.NTPC (Rmgdm) Yet to be informed Pending

92/I/3Complete outage of 220/33kV

KSPDCL SS-5 (Thirumani)

29-06-2020 at 18:01

Hr.

• Triggering incident was tripping of 220kV Pavagada -

Thirumani line due to overvoltage at Thirumani end (only).

Line did not trip at Pavagada end.

• This resulted in complete outage of 220/33kV KSPDCL SS-

5 since the only connected feeder tripped.

i. The SPDs were requested to maintain voltage and prevent injection of reactive power to

grid, especially during night.

ii. SPDs requested to install suitable reactors, if they were not absorbing reactive power, as

the issue would escalate in future with injection of more RE

KSPDCL Yet to be informed Pending

92/II/15

Multiple Tripping in 400kV

NLC TS-2 GS on 28-06-2020

at 15:25Hr.

28-06-2020 at 15:28

Hr

• Triggering incident was failure of R-ph CT of 400kV

NNTPP -Neyveli_TS-II Line at Neyveli_TS-II end. Line

tripped on operation of Differential protection at both the

ends.

• After the tripping of 400kV NNTPP -Neyveli_TS-II Line,

400kV/230kV,ICT - 1 and 2 at Neyveli_TS-II got over loaded

and tripped on operation of overload protection.

• Running units# 2 and 4 at Neyveli_TS-II end and U#1 at

NNTPP also tripped during this event.

i. NLCIL in consultation with TANTRANSCO to avoid overloading of ICTs at NLC

complex.

ii. NLCIL to ensure time synchronization of relays at Neyveli complex. NLCIL

NLICIL mail dated 02.06.2021:

1) Neyveli TS2 ICT Loading is still under discussion between TANTRANSCO,SRPC,SRLDC & NLCIL

2) All realys at Neyveli TS2 all relays are time Synchronized.

Pending

92/III/1Tripping of 400kV JSW

Toranagallu-Guttur line

01-06-2020 at 03:09

Hr.

• Triggering incident was Y -N fault in the line. At JSW end,

line tripped on operation of Z1 distance protection and A/r not

operated.

• At Guttur end, A/r operated successfully and line tripped due

to occurrence of subsequent fault, during reclaim time.

JSWEL to submit a report regrading non-operation of A/R at their end for the subject

tripping incident. JSWEL Yet to be informed Pending

Annexure-C

Page 51 of 52

92/III/2Tripping of 400kV

Ramagundam – Dichippalli line

04-06-2020 at 08:26

Hr.

• Triggering incident was Y-N fault in the line. At

Ramagundam end, fault was sensed in Zone-1, initially Y pole

opened, subsequently R and B poles also opened in 120ms.A/r

not operated.

• At Dichipalli end, fault was sensed in Zone-2, CAT

protection operated and A/r operated. After A/r, line tripped

on operation of Zone-2 due to non-receipt of carrier on

persistent fault.

NTPC(Ramagundam) to submit a report regrading non-operation of A/R at their end for the

tripping. NTPC(RMGDM) Yet to be informed Pending

92/IV/3Tripping of 400 kV

Ramagundam– Dichippalli Line

06-07-2020 at 12:17

Hr.

• Line tripped only at Ramagundam end due to suspected

maloperation of PLCC.

• Line was holding at Dichipalli end.NTPC (Ramagundam) to check the issue of PLCC maloperation at their end for the line. NTPC(RMGDM) Yet to be informed Pending

93/II/15Multiple Tripping at 400/220

kV Ramagundam GS

02-08-2020 at 13:07

Hr.

• Triggering incident was R-N fault in 220 kVRamagundam-

Malayalapalli line-3. At the same time, 400 kVRamagundam -

Dichipalli line tripped only at Ramagundam end on OV Stage

2 operation.

i. NTPC- Ramagundam to submit a report after thoroughchecking of CVT circuit, to sort

out the issue of faultyCVT secondary voltage measurement.

ii. NTPC- Ramagundam in coordination with TSTRANSCO to perform PLCC end-to-end

testing for 400 kV Ramagundam – Dichipalli line.

NTPC-Rmgdm Yet to be informed Pending

94/I/11Complete Outage of 230 kV

BHAVINI

25-Nov-20

22:53 hrs

As per the information received, all connected lines tripped

only at Bhavini end due to Over voltage resulting in complete

loss of supply. Details are awaited.

Bhavini to ensure that DR’s and EL’s of all protection relays are configured properly with

all required protection (digital & analog) signals.Bhavini Yet to be informed Pending

97/III/12Tripping of 400 kV Neyveli TS

2 - Pugalur line

04-Jun-2021,

19:27:00 hrs.

Triggering incident was R-N fault in the line. At Neyveli TS-2

end, the Pugalur feeder was connected to Transfer Bus. Due

to fault in R phase, all the three phases of the Transfer bus

breaker got tripped. At Pugalur end, fault was sensed in Zone-

1, A/R operated and line was holding.

NLCIL to take steps to restore Main Bus immediately at their NLC TS2 station, and enable

A/R on 400 kV NLC TS2 – Pugalur line.NLCIL Yet to be informed

Annexure-C

Page 52 of 52

Sl.No ID ELE_NAME Outage_Date Outage_time Revival_Date Revival_Time REASON SENDER / RECEIVER Remedial_measures RM by constituents

145692621

230KV-TIRUNELVELI-UDAYATHOOR 02-01-2022 01:54:00 02-01-202202:25:00

Y PHASE TO GROUNG FAULT TANTRANSCO

210

400KV-YELHANKA-NELAMANGALA-1 04-01-2022 15:45 04-01-202223:17:00

R-N FAULT KPTCL

311

400KV-YELHANKA-NELAMANGALA-1 04-01-2022 15:45 04-01-202223:17:00

R-N FAULT KPTCL

412

400KV-GAZUWAKA-JEYPORE-2 05-01-2022 13:37 05-01-202215:54:00

R-N FAULT APTRANSCO/PGCIL SR-I

513

400KV-NCTPS_STAGE_II-VALLUR-2 06-01-2022 19:39

A PHASE, ZONE 1 TRIP, @

NCTPS END, 29.16KA, TANTRANSCO/NTECL/TANGEDCO

614

400KV-URAVAKONDA-MEHBOOBNAGAR-1 08-01-2022 00:11

Y PHASE TO GROUNG FAULT APTRANSCO/TSTRANSCO

715

400KV/220KV GOOTY-ICT-1 08-01-2022 19:46 08-01-202222:20:00

220kv bus bar protection

operated PGCIL SR-l

816

400KV/220KV GOOTY-ICT-2 08-01-2022 19:46 08-01-202222:22:00

220kV Bus bar operated PGCIL SR-l

917

400KV/220KV GOOTY-ICT-3 08-01-2022 19:46 08-01-202222:21:00

220kV Bus bar operated PGCIL SR-l

1024

HVDC 800KV PUGALUR HVDC Pole 1 11-01-2022 10:51 11-01-202217:30:00

DC line faultPGCIL SR-ll

1125

HVDC 800KV PUGALUR HVDC Pole 3 11-01-2022 10:51 11-01-202212:40:00

DC line faultPGCIL SR-ll

1226

HVDC 500KV TALCHER Pole 1 11-01-2022 15:43

DC Busbar Protection TripPGCIL SR-l

1327

220KV-THENI-SABARIGIRI-1 11-01-2022 14:19 11-01-202214:40:00

R-N FAULTTANTRANSCO/KSEBL

1428

HVDC800KV-RAIGARH HVDC-PUGALUR HVDC-1 11-01-2022 10:51 11-01-202212:25:00

Line fault 1176.4 kms from

pugalur PGCIL SR-ll

1556

400KV-HINDUJA-KV_KOTA-2 14-01-2022 05:40 14-01-202205:55:00

Tripped only at KV KOTA; No

relay indications HNPCL/APTRANSCO

1659

400KV-CUDDAPAH-KOLAR_AC-1 16-01-2022 02:00

TRIPPED ON OVPGCIL SR-l/PGCIL SR-ll

1760

400KV-SALEM-UDUMALPET_PG-2 19-01-2022 19:38 20-01-202201:17:00

Y-PHASE LA FAILURETANTRANSCO/PGCIL SR-II TSTRANSCO: Substations does

not belongs to TSTRANSCO.

1861

400KV/220KV GOOTY-ICT-1 20-01-2022 20:12 20-01-202221:26:00

TRIPPED DUE TO DOWN

STREAM FAULT PGCIL SR-l/APTRANSCO

1962

400KV/220KV GOOTY-ICT-2 20-01-2022 20:12 20-01-202221:28:00

TRIPPED DUE TO DOWN

STREAM FAULT PGCIL SR-l/APTRANSCO TSTRANSCO: Substations does


2063

400KV/220KV GOOTY-ICT-3 20-01-2022 20:12 20-01-202221:30:00

TRIPPED DUE TO DOWN

STREAM FAULTPGCIL SR-l/APTRANSCO

2164

400KV-NCTPS_STAGE_II-MANALI-1 20-01-2022 13:11 20-01-202217:59:00 B-N FAULT TANTRANSCO/TANGEDCO TSTRANSCO: Substations does


2266

400KV-NCTPS_STAGE_II-MANALI-1 20-01-2022 19:42

TRIPPED ON R-N FAULT, If-

32kA 0.1kms from North

chennai end

TANTRANSCO/TANGEDCO TSTRANSCO: Substations does


Pending Remedial Measures/ Actions taken for the Critical Tripping Incidents (as on 24.02.2022)

Annexure-D

Page 1 of 6

2369

132KV-KASUMANCHI-CHILLAKALLU-1 21-01-2022 21:39 21-01-202221:53:00

tripped on r-n fault, 2.9ka

from chilakkallu endTSTRANSCO/APTRANSCO Fault location of 32.8Km falls in

TSTRANSCO juridiction.

2474

230KV-KALVENDAPATTU-VEERAPURAM 22-01-2022 12:43 22-01-202218:35:00 R-B FAULT TANTRANSCO TSTRANSCO: Substations does


2576

400KV-KAIGA-GUTTUR-1 22-01-2022 11:03 22-01-202214:11:00 auto reclosure unsuccessful KPTCL/NPCIL-KGS TSTRANSCO: Substations does


2678

220KV-HASSAN-MRS SHIMOGA-1 23-01-2022 15:17 23-01-202217:25:00 Tripped on Y-B Fault KPTCL TSTRANSCO: Substations does


2780

230KV-KALVENDAPATTU-THARAMANI 25-01-2022 17:13 25-01-202218:10:00

220KV bus failure at

Ambewadi S/sTANYTRANSCO TSTRANSCO: Substations does


2882

230KV-KUDANKULAM-S R PUDUR 26-01-2022 22:35 27-01-202200:29:00 R-N FAULT TANTRANSCO/KKNPP TSTRANSCO: Substations does


2983

765KV-CHILAKALURIPETA-VEMAGIRI_PG-2 26-01-2022 12:54DISTANCE PROTECTION APGENCO/TSTRANSCO TSTRANSCO: Substations does


3084

220KV-HASSAN-GOPALPURA-1 28-01-2022 15:02 28-01-202221:24:00

THREE PHASE TO GROUND

FAULTKPTCL

3185

220KV-HASSAN-YECHANAHALLI-1 28-01-2022 15:02 28-01-202221:29:00 B-N FAULT KPTCL

3289

220KV-AMBEWADI-XELDEM-1 30-01-2022 13:09 30-01-202217:57:00 B-C PHASE FAULT KPTCL/GED

3392

220KV-EDAMON-EDAPPON-1 01-02-2022 07:34 01-02-202212:54:00

Tripped due to DC Bus

differential protectionKSEBL

3493

220KV-SRISAILAM_RIGHT_BANK-DINDI-1 02-02-2022 20:14 02-02-202222:15:00 220 kV BUS BAR OPERATED APGENCO/TSTRANSCO

3594

220KV-SRISAILAM_RIGHT_BANK-NAGARJU .. 02-02-2022 20:14 02-02-202222:18:00 220 kV BUS BAR OPERATED APGENCO/TSTRANSCO

3695

220KV-DOMALAPENTA-SRISAILAM_RIGHT_ .. 02-02-2022 20:14 02-02-202222:16:00 220 kV BUS BAR OPERATED TSTRANSCO/APGENCO

3796

230KV-TIRUNELVELI-UDAYATHOOR 02-02-2022 06:28 02-02-202214:53:00 R-N FAULT TANTRANSCO

3897

423 Tie Bay (423) of 400KV-SATTENPALLY-CHILAKALURIPETA-2 AND SATTENPALLY - 400KV B/R 1 @SATTENPALLY - 400KV02-02-2022 13:07 02-02-202220:55:00

Trip relay operated due to

wiring issueAPTRANSCO/PGCIL SR-l

39102

220KV-KOCHI-BRAHMPURAM-2 04-02-2022 08:53 04-02-202209:32:00 INTER TRIP RELAY ACTED PGCIL SR-II/ KSEBL

4098

400KV/220KV GAZUWAKA-ICT-2 04-02-2022 10:45 04-02-202213:45:00

due to bus bar operation at

220kV VSSPGCIL SR-l

4199

220KV-KADAKOLA-KANIYAMPETTA 04-02-2022 06:13 04-02-202216:09:00 R-N FAULT KPTCL/KSEBL

42100

220KV-MYSORE-GOPALPURA-1 04-02-2022 21:55 04-02-202222:45:00

220 kV BusBar Operated at

gopalpuraKPTCL

43101

220KV-IDDUKI-UDUMALPET-1 04-02-2022 13:44 04-02-202220:52:00 TRIPPED ON Y-N FAULT TANTRANSCO/ KSEBL

44103

220KV-KOCHI-BRAHMPURAM-2 04-02-2022 15:54 04-02-202216:48:00

Line 2 tripped while charging

line 1PGCIL SR-II/ KSEBL

45104

220KV-HASSAN-GOPALPURA-1 04-02-2022 21:56 04-02-2022


gopalpuraKPTCL

46143

400KV/220KV GAZUWAKA-ICT-2 04-02-2022 10:45 04-02-202213:45:00

due to bus bar operation at

220kV VSSPGCIL SR-l

Annexure-D

Page 2 of 6

47144

220KV-KADAKOLA-KANIYAMPETTA 04-02-2022 06:13 04-02-202216:09:00 R-N FAULT KPTCL/KSEBL

48145

220KV-MYSORE-GOPALPURA-1 04-02-2022 21:55 04-02-202222:45:00


gopalpuraKPTCL

49146

220KV-IDDUKI-UDUMALPET-1 04-02-2022 13:44 04-02-202220:52:00 TRIPPED ON Y-N FAULT TANTRANSCO/ KSEBL

50147

220KV-KOCHI-BRAHMPURAM-2 04-02-2022 08:53 04-02-202209:32:00 INTER TRIP RELAY ACTED PGCIL SR-II/ KSEBL

51148

220KV-KOCHI-BRAHMPURAM-2 04-02-2022 15:54 04-02-202216:48:00

Line 2 tripped while charging

line 1PGCIL SR-II/ KSEBL

52149

220KV-HASSAN-GOPALPURA-1 04-02-2022 21:56 04-02-2022


gopalpuraKPTCL

53105

400KV-KAIGA-GUTTUR-1 05-02-2022 05:17 06-02-2022TRIPPED ON B-N FAULT NPCIL/ KPTCL

54106

400KV/110KV KANARPATTI-ICT-3 05-02-2022 14:19 05-02-202216:03:00

at 110 KV PUDUR SS, 33 KV Y

Phase LAS got burstTANTRANSCO

55107




56108

220KV-KADAKOLA-KANIYAMPETTA 05-02-2022 13:11 05-02-202215:09:00 R-G FAULT KPTCL/KSEBL

57150

400KV-KAIGA-GUTTUR-1 05-02-2022 05:17 06-02-2022TRIPPED ON B-N FAULT NPCIL/ KPTCL

58151




59152




60153

220KV-KADAKOLA-KANIYAMPETTA 05-02-2022 13:11 05-02-202215:09:00 R-G FAULT KPTCL/KSEBL

61 109 400KV-KAIGA-GUTTUR-1 06-02-2022 19:40 06-02-2022 TRIPPED ON Y-N FAULT NPCIL/ KPTCL

62 154 400KV-KAIGA-GUTTUR-1 06-02-2022 19:40 06-02-2022 TRIPPED ON Y-N FAULT NPCIL/ KPTCL

63 110 220KV-THENI-SABARIGIRI-1 07-02-2022 15:39 07-02-2022 16:37:00

tripped due to DC FAILURE

and TRANSFORMER OF

BATTERY CHARGER FAILED TANTRANSCO/ KSEBL

64 111 400KV-GOOTY-NELAMANGALA-1 07-02-2022 13:07 07-02-2022 13:43:00 R-N FAULT PGCIL SR-I/ KPTCL

65 155 220KV-THENI-SABARIGIRI-1 07-02-2022 15:39 07-02-2022 16:37:00

tripped due to DC FAILURE

and TRANSFORMER OF

BATTERY CHARGER FAILED TANTRANSCO/ KSEBL

66 156 400KV-GOOTY-NELAMANGALA-1 07-02-2022 13:07 07-02-2022 13:43:00 R-N FAULT PGCIL SR-I/ KPTCL

67 112 220KV-SRISAILAM_RIGHT_BANK-DINDI-1 08-02-2022 15:52 08-02-2022 17:20:00

bus bar protection operated

at 220kv Srisailem right bank APGENCO/ TSTRANSCO

Annexure-D

Page 3 of 6

68 113 220KV-SRISAILAM_RIGHT_BANK-NAGARJU .. 08-02-2022 15:52 08-02-2022 17:15:00

Bus bar protection operated

at 220kV Srisailam Right

bank APGENCO/ TSTRANSCO

69 114 220KV-HIRIYUR_OSTRO-HIRIYUR-1 08-02-2022 16:15 08-02-2022 17:09:00

Due to overcurrent relay

protection KPTCL/ OSTRO KANNADA

70 115 220KV-DOMALAPENTA-SRISAILAM_RIGHT_ .. 08-02-2022 15:52 08-02-2022 17:19:00


at 220kv Srisailem right bank TSTRANSCO/ APGENCO

71 116 400KV-GUTTUR-HIRIYUR-1 08-02-2022 14:52 08-02-2022 16:00:00 TRIPPED ON C-N FAULT KPTCL/ PGCIL SR-ll

72 157 220KV-SRISAILAM_RIGHT_BANK-DINDI-1 08-02-2022 15:52 08-02-2022 17:20:00


at 220kv Srisailem right bank APGENCO/ TSTRANSCO

73 158 220KV-SRISAILAM_RIGHT_BANK-NAGARJU .. 08-02-2022 15:52 08-02-2022 17:15:00

Bus bar protection operated

at 220kV Srisailam Right

bank APGENCO/ TSTRANSCO

74 159 220KV-HIRIYUR_OSTRO-HIRIYUR-1 08-02-2022 16:15 08-02-2022 17:09:00

Due to overcurrent relay

protection KPTCL/ OSTRO KANNADA

75 160 220KV-DOMALAPENTA-SRISAILAM_RIGHT_ .. 08-02-2022 15:52 08-02-2022 17:19:00


at 220kv Srisailem right bank TSTRANSCO/ APGENCO

76 161 400KV-GUTTUR-HIRIYUR-1 08-02-2022 14:52 08-02-2022 16:00:00 TRIPPED ON C-N FAULT KPTCL/ PGCIL SR-ll

77 162 220KV-WARANGAL-NAGARAM-1 09-02-2022 23:01 09-02-2022 23:20:00 R-N FAULT TSTRANSCO

78 117 220KV-WARANGAL-NAGARAM-1 09-02-2022 23:01 09-02-2022 23:20:00 R-N FAULT TSTRANSCO

79 118 HVDC 800KV PUGALUR HVDC Pole 2 10-02-2022 17:33 10-02-2022 18:41:00

Pole blocked with Protection

action initiated from Raigarh

end PGCIL SR-ll




end PGCIL SR-ll

81 120 220KV-HIRIYUR-SIRA-2 10-02-2022 10:59 10-02-2022 12:53:00

tripped due to DC failure in

main-1 relay at Sira KPTCL

82 121 HVDC800KV-RAIGARH HVDC-PUGALUR HVDC-2 10-02-2022 17:33 10-02-2022 18:41:00

Line outage due to tripping

of Pole 2 & 4 at both ends PGCIL SR-ll




end PGCIL SR-ll




end PGCIL SR-ll

85 165 220KV-HIRIYUR-SIRA-2 10-02-2022 10:59 10-02-2022 12:53:00

tripped due to DC failure in

main-1 relay at Sira KPTCL

86 166 HVDC800KV-RAIGARH HVDC-PUGALUR HVDC-2 10-02-2022 17:33 10-02-2022 18:41:00

Line outage due to tripping

of Pole 2 & 4 at both ends PGCIL SR-ll


Spurious triggering of events

caused tripping of Pole 4 PGCIL SR-ll

88 123 400KV-RTPS-BTPS-1 11-02-2022 07:50 11-02-2022 12:01:00 tripped due to cb flash over KPCL

89 124 400KV-RAICHUR_PG-RTPS-1 11-02-2022 06:42 11-02-2022 11:21:00

BUS BAR PROTECTION

OPERATED PGCIL SR-l/ KPCL


Spurious triggering of events

caused tripping of Pole 4 PGCIL SR-ll

91 168 400KV-RTPS-BTPS-1 11-02-2022 07:50 11-02-2022 12:01:00 tripped due to cb flash over KPCL

Annexure-D

Page 4 of 6

92 169 400KV-RAICHUR_PG-RTPS-1 11-02-2022 06:42 11-02-2022 11:21:00

BUS BAR PROTECTION

OPERATED PGCIL SR-l/ KPCL

93 125 400KV/220KV GUTTUR-ICT-2 12-02-2022 18:53 12-02-2022 22:22:00

TRIPPED ON BUCCHOLZ

RELAY OPERATION KPTCL

94 170 400KV/220KV GUTTUR-ICT-2 12-02-2022 18:53 12-02-2022 22:22:00

TRIPPED ON BUCCHOLZ

RELAY OPERATION KPTCL

95 127 132KV-WADAPALLI-PIDUGURALLA-1 13-02-2022 05:22 R-N FAULT TSTRANSCO/ APTRANSCO

96 128 220KV-AMBEWADI-XELDEM-1 13-02-2022 13:43 13-02-2022 14:15:00 B-N FAULT KPTCL/ GED

97 126 132KV-GUNTAKAL-HAMPI-1 13-02-2022 02:55 13-02-2022 03:14:00 R phase to ground fault APTRANSCO

98 129 400KV-JULURUPADU-MANUGURU-2 13-02-2022 15:03 13-02-2022 22:37:00 B-N FAULT TSTRANSCO/ TSGENCO

99 171 132KV-GUNTAKAL-HAMPI-1 13-02-2022 02:55 13-02-2022 03:14:00 R phase to ground fault APTRANSCO

100 172 132KV-WADAPALLI-PIDUGURALLA-1 13-02-2022 05:22 R-N FAULT TSTRANSCO/ APTRANSCO

101 173 220KV-AMBEWADI-XELDEM-1 13-02-2022 13:43 13-02-2022 14:15:00 B-N FAULT KPTCL/ GED

102 174 400KV-JULURUPADU-MANUGURU-2 13-02-2022 15:03 13-02-2022 22:37:00 B-N FAULT TSTRANSCO/ TSGENCO

103 130 400KV/220KV GAJWEL-ICT-1 14-02-2022 07:35 14-02-2022 09:04:00

220kv bus bar operated due

to breaker lockout in

medchal line TSTRANSCO

104 131 400KV/220KV GAJWEL-ICT-1 14-02-2022 10:39 14-02-2022 16:20:00

220KV bus1 bus bar

protection operated TSTRANSCO

105 132 400KV/220KV GAJWEL-ICT-2 14-02-2022 07:35 14-02-2022 10:38:00




106 133 400KV/220KV GAJWEL-ICT-3 14-02-2022 07:35 14-02-2022 08:45:00




107 134 400KV/220KV GAJWEL-ICT-3 14-02-2022 10:39 14-02-2022 11:24:00

220KV bus1 bus bar


108 135 400KV/220KV GAJWEL-ICT-4 14-02-2022 07:35 14-02-2022 17:25:00




109 175 400KV/220KV GAJWEL-ICT-1 14-02-2022 07:35 14-02-2022 09:04:00




110 176 400KV/220KV GAJWEL-ICT-1 14-02-2022 10:39 14-02-2022 16:20:00

220KV bus1 bus bar


111 177 400KV/220KV GAJWEL-ICT-2 14-02-2022 07:35 14-02-2022 10:38:00




112 178 400KV/220KV GAJWEL-ICT-3 14-02-2022 07:35 14-02-2022 08:45:00




113 179 400KV/220KV GAJWEL-ICT-3 14-02-2022 10:39 14-02-2022 11:24:00

220KV bus1 bus bar


114 180 400KV/220KV GAJWEL-ICT-4 14-02-2022 07:35 14-02-2022 17:25:00




115 136 132KV-KUZHITHURAI-PARASSALA-1 15-02-2022 22:38 15-02-2022 23:17:00

tripped and no indication on

realy TANTRANSCO/ KSEBL

Annexure-D

Page 5 of 6

116 181 132KV-KUZHITHURAI-PARASSALA-1 15-02-2022 22:38 15-02-2022 23:17:00

tripped and no indication on

realy TANTRANSCO/ KSEBL

117 137 400KV/220KV RAYADURG-ICT-2 17-02-2022 12:20

DIFFERENTIAL PROTECTION

OPERATED TSTRANSCO

118 138 220KV-YERRAANDAHALLI-HOSUR-1 17-02-2022 14:02 17-02-2022 14:50:00

Tripped at Yerandahalli due

to Y-N fault KPTCL/ TANTRANSCO

119 182 400KV/220KV RAYADURG-ICT-2 17-02-2022 12:20

DIFFERENTIAL PROTECTION

OPERATED TSTRANSCO

120 183 220KV-YERRAANDAHALLI-HOSUR-1 17-02-2022 14:02 17-02-2022 14:50:00

Tripped at Yerandahalli due

to Y-N fault KPTCL/ TANTRANSCO

121 139 400KV/220KV MARADAM-ICT-2 18-02-2022 16:35 18-02-2022 18:04:00

tripped due to DT Received

signal from kalpaka end bay

(410 and 411 bays ) got APTRANSCO

122 184 400KV/220KV MARADAM-ICT-2 18-02-2022 16:35 18-02-2022 18:04:00

tripped due to DT Received

signal from kalpaka end bay

(410 and 411 bays ) got APTRANSCO

123 140 765KV-KURNOOL_PG-RAICHUR_PG-2 19-02-2022 19:58 20-02-2022 00:08:00 TRIPPED ON Y-N FAULT PGCIL SR-l

124 185 765KV-KURNOOL_PG-RAICHUR_PG-2 19-02-2022 19:58 20-02-2022 00:08:00 TRIPPED ON Y-N FAULT PGCIL SR-l

125 141 230KV-HOSUR_PG-TIRUPATTUR 20-02-2022 12:49 20-02-2022 14:13:00 R-G FAULT TANTRANSCO/ PGCIL-SR-2

126 142 230KV-TIRUNELVELI-VEERANAM-2 20-02-2022 13:48 20-02-2022 19:26:00 Tripped on Y-B Fault TANTRANSCO

127 186 230KV-HOSUR_PG-TIRUPATTUR 20-02-2022 12:49 20-02-2022 14:13:00 R-G FAULT TANTRANSCO/ PGCIL-SR-2

128 187 230KV-TIRUNELVELI-VEERANAM-2 20-02-2022 13:48 20-02-2022 19:26:00 Tripped on Y-B Fault TANTRANSCO

129 188 400KV-KALPAKKA-ASUPAKA-1 22-02-2022 11:19 22-02-2022 18:42:00 R-N FAULT APTRANSCO/TSTRANSCO

130 189 400KV-MARADAM-KALPAKKA-1 22-02-2022 12:01 22-02-2022 12:08:00 DT RECEIVED APTRANSCO

131 190 400KV-MARADAM-KALPAKKA-2 22-02-2022 12:01 22-02-2022 12:09:00 DT RECEIVED APTRANSCO

132 191 400KV-DONI-GUTTUR-1 22-02-2022 15:16 22-02-2022 19:07:00 R-N FAULT KPTCL

133 192 400KV-KALVENDAPATTU-NNTPP-1 22-02-2022 06:30 Y phase to Ground fault TANTRANSCO/ NNTPP

134 196 400KV-RAICHUR_PG-RTPS-1 23-02-2022 09:42 23-02-2022 10:40:00 DT RECEIVED KPTCL/ PGCIL_SR-1

135 193 KALPAKKA - 400KV B/R 2 23-02-2022 07:41 23-02-2022 19:01:00 Tripped on PRD operation APTRANSCO

136 194 400KV/220KV MEHBOOBNAGAR-ICT-1 23-02-2022 08:44 R-ph HV Limb failure TSTRANSCO

137 195 220KV-RAMAGUNDAM-MALYALAPALLI-3 23-02-2022 06:04 23-02-2022 16:52:00 R-N FAULT NTPC/ TSTRANSCO

138 197 400KV-KHAMMAM_PG-ASUPAKA-1 23-02-2022 13:09 23-02-2022 13:39:00 B-N FAULT PGCIL SR-I/TSTRANSCO

139 198 400KV-KALVENDAPATTU-NNTPP-1 23-02-2022 13:14 R-N FAULT TANTRANSCO/ NNTPP

Annexure-D

Page 6 of 6

Complete Outage of 400kV RYTPP Generating Station of APGENCO on 09-12-2021 at 23:25 Hrs

I.A.1

Brief Analysis : During antecedent conditions, 400kV Kalikiri RYTPP Line -1 was under outage. Triggering incident was hand tripping of 400kV Kalikiri RYTPP Line -2 to contain over voltage at RYTPP end. Since both the lines connected to RYTPP got tripped, this resulted in complete outage of 400kV RYTPP generating station. There was no generation in RYTPP during this event.

Generation Loss = 0 MW Load Loss = 0 MW

Annexure-E

Page 1 of 36


I.A.1

PMU Analysis

Annexure-E

Page 2 of 36

Complete Outage of 220kV/66kV Kolar_KA SS, 220kV/66kV Chintamani SS, 220kV/66kV Malur, 220kV/66kV Sarjapura and

220kV/66kV VTP SS of KPTCL at 14:52hrs on 12-12-2021

I.A.2

Brief Analysis : 220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS are radially fed from 400kV/220kV Kolar_PG. Since 220kV Malur-Hoody line was kept open for Circuit Breaker replacement work at 220kV Malur station, 220kV/66kV Malur, 220kV/66kV Sarjapur and 220kV/66kV VTP SS were radially fed from 220kV Kolar SS during the incident. During antecedent conditions, all poles of Pugalur HVDC were under shutdown. Triggering incident was maloperation of Pugalur HVDC SPS, while doing a software update in Pugalur HVDC PCs. Immediately, backup protection initiated and SPS operated tripping 220kV Kolar_PG Kolar_KA Line-1&2 and 220kV kolar_PG Chintamani Line-1&2. This resulted in complete outage of 220kV/66kV Kolar_KA SS and 220kV/66kV Chintamani SS, 220kV/66kV Malur, 220kV/66kV Sarjapur and 220kV/66kV VTP SS of KPTCL.


Annexure-E

Page 3 of 36

Complete Outage of 220kV/66kV Kolar_KA SS, 220kV/66kV Chintamani SS, 220kV/66kV Malur, 220kV/66kV Sarjapura and

220kV/66kV VTP SS of KPTCL at 14:52hrs on 12-12-2021

I.A.2

PMU Analysis

Annexure-E

Page 4 of 36

Complete Outage of 220kV Kadra PH, 220kV Kodasalli PH of KPCL and 220kV/110kV Karwar SS of KPTCL on 26-12-2021 at 08:56 Hrs

I.A.3

Brief Analysis : During antecedent conditions, 220 kV Kaiga-Kadra and 220 kV Kaiga-Kodsalli were in idle charged condition. As per the report submitted, Y-phase pole discrepancy relay operated while de synchronising unit-2 at Kodasally. At the same time, Unit-1 LBB operated and all the elements connected to 220kV Bus got tripped. This resulted in complete outage of 220kV Kadra PH, 220kV Kodasalli PH of KPCL. This also resulted in complete outage of 220kV/110kV Karwar SS due to incoming supply failure from 220kV kodsalli PH.


Annexure-E

Page 5 of 36

Complete Outage of 220kV Kadra PH, 220kV Kodasalli PH of KPCL and 220kV/110kV Karwar SS of KPTCL on 26-12-2021 at 08:56 Hrs

I.A.3

PMU Analysis

Annexure-E

Page 6 of 36

Complete Outage of 220kV Gooty _SWS of APTRANSCO on 08-01-2022 at 19:46 Hrs

I.A.4

Brief Analysis : As per the report submitted, Y-phase insulator string of 220kV Gooty_SWS Bus-1 got failed and fell on 220kV Boyareddipalli line R-phase Jumper at 220kV Gooty_SWS end. Immediately, BBP of 220kV Bus 1 & 2 operated and all the elements connected to the buses got tripped. This resulted in complete outage of 220kV Gooty_SWS.


Annexure-E

Page 7 of 36

Complete Outage of 220kV Gooty _SWS of APTRANSCO on 08-01-2022 at 19:46 Hrs

I.A.4

PMU Analysis

Annexure-E

Page 8 of 36


I.A.5

Brief Analysis : During antecedent conditions, 400kV Kalikiri RYTPP Line -2 was under outage. Triggering incident was tripping of 400kV Kalikiri RYTPP Line -1 on over voltage stage-1 protection at RYTPP end and DT was received at Kalikiri end. Since both the lines connected to RYTPP got tripped, this resulted in complete outage of 400kV RYTPP generating station. There was no generation in RYTPP during this event.


Annexure-E

Page 9 of 36


I.A.5

PMU Analysis

Annexure-E

Page 10 of 36

Complete Outage of 220kV Gooty_SWS and Multiple Trippings in 220kV/132kV Gooty_RS of APTRANSCO on 20-01-2022 at

20:12 Hrs

I.A.6

Brief Analysis : As per the report submitted, triggering incident was failure of B-ph CT of 220kV Gooty_SWS Gooty_RS line at 220kV Gooty_RS end. At 200kV/132kV Gooty_RS, 220kV side BBP operated and all the connected elements got tripped. 132kV Gooty_RS was intact during this event. At 220kV Gooty_SWS, Gooty_RS feeder was not tripped and all the connected source feeders got tripped at remote ends including 400kV/220kV Gooty_PG ICT#1,2, and 3. This resulted in complete outage of 220kV Gooty_SWS.


Annexure-E

Page 11 of 36

Complete Outage of 220kV Gooty_SWS and Multiple Trippings in 220kV/132kV Gooty_RS of APTRANSCO on 20-01-2022 at

20:12 Hrs

I.A.6

PMU Analysis

Annexure-E

Page 12 of 36

Complete Outage of 230kV/110kV Taramani SS of TANTRANSCO on 25-01-2022 at

17:14 Hrs

I.A.7

Brief Analysis : As per the report submitted, trigering incident was operation of 230kV Bus- A and Bus-B BBP while charging 230kV Bus- B at 230kV/110kV Taramani SS. All the feeders connected to 230kV bus bars got tripped and this resulted in complete outage of 230kV/110kV Taramani SS.


Annexure-E

Page 13 of 36

Complete Outage of 230kV/110kV Taramani SS of TANTRANSCO on 25-01-2022 at

17:14 Hrs

I.A.7

PMU Analysis

Annexure-E

Page 14 of 36

Complete Outage of 220kV/132kV Parawada SS of APTRANSCO on 28-01-2022 at

06:49 Hrs

I.A.8

Brief Analysis : During antecedent conditions, 220kV/132kV Parawada SS was radially fed from 220kV VSS due to outage of 220kV Parawada Anrak line. As per the report submitted, triggering incident was R-phase jumper failure in 220kV Parawada VSS line and the line got tripped at both the ends on operation of Earth Fault protection. Due to tripping of only connected line, there was complete loss of supply at 220kV/132kV Parawada SS.


Annexure-E

Page 15 of 36

Complete Outage of 220kV/132kV Parawada SS of APTRANSCO on 28-01-2022 at

06:49 Hrs

I.A.8

PMU Analysis

Annexure-E

Page 16 of 36

Complete Outage of 220kV/33kV Ostro Kannada Wind Plant on 03-12-2021 at 19:16 Hrs

I.B.1

Brief Analysis : As per the report submitted, triggering incident was tripping of a 33kV feeder at Ostro end due to 3-phase fault. At the same time, 220kV Hiriyur Ostro Kannada line and 220kV/33kV 160MVA Transformer tripped on suspected maloperation of Over current relay at Ostro kannada end. 220kV Hiriyur Ostro Kannada line was holding at Hiriyur end. Due to tripping of the only connected line, there was complete outage of 220kV/33kV Ostro Kannada Wind Plant.


Annexure-E

Page 17 of 36

Complete Outage of 220kV/33kV Ostro Kannada Wind Plant on 03-12-2021 at 19:16 Hrs

PMU Analysis

I.B.1 Annexure-E

Page 18 of 36

Tripping of 230kV Bus-1&2 of 400kV/230kV Kudankulam Nuclear GS of NPCIL on 06-12-2021 at

21:41 Hrs

II.1

Brief Analysis : As per the report submitted, triggering incident tripping of all the elements connected to 230kV Bus-1 and 2 of 400kV/230kV Kundankulam Nuclear Generating Station due to operation of 230kV Bus-1 and Bus-2 BBP.


Annexure-E

Page 19 of 36

Tripping of 230kV Bus-1&2 of 400kV/230kV Kudankulam Nuclear GS of NPCIL on 06-12-2021 at

21:41 Hrs

II.1

PMU Analysis

Annexure-E

Page 20 of 36

Tripping of HVDC VSC 320KV- PUGALUR THRISSUR Pole -1 on 17-12-2021 at 07:46 Hrs

II.2

Brief Analysis : Pole-1 tripped due to CWC (convertor water cooling) trip. AC supply fault was in UPS which results in both UPS going into battery operation and pump change over didn't take place. Findings and remedial actions taken shall be furnished.


Annexure-E

Page 21 of 36


II.2

PMU Analysis

Annexure-E

Page 22 of 36


II.2

PMU Analysis

Annexure-E

Page 23 of 36

Tripping of 400/220kV ICT-1 at RAICHUR on 18-12-2021 at 10:16 Hrs

II.3

Brief Analysis : As per the report submitted, triggering incident was operation of 33KV side ZIGZAG transformer Earth fault relay. Tripping is not in order as the zigzag transformer was not in service. Tripping needs review. Findings and remedial actions taken shall be furnished.


Annexure-E

Page 24 of 36

Tripping of 400/220kV ICT-1 at RAICHUR on 18-12-2021 at 10:16 Hrs

II.3

PMU Analysis

Annexure-E

Page 25 of 36

Tripping of 400kV RAICHUR - BTPS on 23-12-2021 at 03:45 Hrs

II.4

Brief Analysis : As per the report submitted, the triggering incident was RN fault in the line. A/r is in non-auto mode since both the ends are connected to generators. The fault was sensed in Zone-1 at both ends. At Raichur end, line tripped on 3ph Zone-1 distance protection. At BTPS end, as per DR, even after 3 phase trip, after 100ms from the opening of breakers, the fault was observed and the same needs review.


Annexure-E

Page 26 of 36

Tripping of 400kV RAICHUR - BTPS on 23-12-2021 at 03:45 Hrs

II.4

PMU Analysis

Annexure-E

Page 27 of 36

Tripping of 400kV- PAVAGADA- TUMKUR-2 on 24-12-2021 at 10:41 Hrs

II.5

Brief Analysis : During antecedent conditions, while test charging, 400kV Pavagada Tumkur Line-1 was under charged condition at Pavagada end and open at Tumkur end. Triggering incident was, R-N fault in Pavagada Tumkur line-1. At Pavagada end of 400kV Pavagada Tumkur Line-1, fault was sensed in zone-2 and line got tripped with a delay of 480ms. At Tumkur end of 400kV Pavagada Tumkur Line-2, the same fault was sensed as R-B fault in zone-2 and line got tripped with a delay of 360ms. Zone-2 clearance time of Tumkur of 400kV Pavagada Tumkur Line-2 is less than Pavagada end of 400kV Pavagada Tumkur Line-1 and this led to tripping of 400kV Pavagada Tumkur Line-2 at Tumkur end. Tripping is not in order and needs review.


Annexure-E

Page 28 of 36

Tripping of 400kV- PAVAGADA- TUMKUR-2 on 24-12-2021 at 10:41 Hrs

II.5

PMU Analysis

Annexure-E

Page 29 of 36

Tripping of 110kV Bus-1 at 220kV/110kV Madakathara SS of KSEB on 20-01-2022 at 11:37 Hrs

II.6

Brief Analysis : As per the report submitted, all the elements were connected to 110kV Bus-1 at 220kV/110kV Madakathara SS since 110kV Bus-2 was under planned outage. Triggering incident was R phase fault in 110kV Bus-1. Due to non-operation of 110kV Bus-1 BBP, fault was cleared by tripping of transfomers and feeders at remote ends. This resulted in 110kV side bus de-energization of 220kV/110kV Madakathara SS.


Annexure-E

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Tripping of 110kV Bus-1 at 220kV/110kV Madakathara SS of KSEB on 20-01-2022 at 11:37 Hrs

II.6

PMU Analysis

Annexure-E

Page 31 of 36

Tripping of 220kV ASUPAKA - LOWER_SILERU-1 on 20-01-2022 at 22:48 Hrs

II.7

Brief Analysis : As per the report submitted, triggering incident was Y-N fault in the line at a distance of 21KM from Asupaka end. At both the ends, fault was sensed in zone-1. At Asupaka end, A/R operated line tripped on persistent fault in zone-1. At Lower Sileru end, A/r operated and line tripped on operation of zone-1 with a delay of 400ms after reclose. Delayed fault clearance at Lower Sileru end needs review.


Annexure-E

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II.7

PMU Analysis

Annexure-E

Page 33 of 36


II.7

PMU Analysis

Annexure-E

Page 34 of 36

Tripping of 400kV KAIGA - GUTTUR 1 on 22-01-2022 at 11:03 Hrs

II.8

Brief Analysis : As per the report submitted, line tripped at Kaiga end on operation of OV St-2 protection instantaneously.


Annexure-E

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Tripping of 400kV KAIGA - GUTTUR 1 on 22-01-2022 at 11:03 Hrs

II.8

PMU Analysis

Annexure-E

Page 36 of 36

26 February 2022 - Southern Regional Power Committee

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Transcript of 26 February 2022 - Southern Regional Power Committee