SOUTHERN REGIONAL POWER COMMITTEE - SRPC

Minutes of the Special Meeting on Pending Protection Issues of Puducherry Stations held on 20th July, 2018 Page 1

SOUTHERN REGIONAL POWER COMMITTEE BENGALURU

Minutes of the Special Meeting on the Pending Protection Issues of Puducherry Substations held on 20th July, 2018

A. Introduction

A Special Meeting was held on 20th July, 2018 at PED HQ, Puducherry to deliberate on all outstanding

protection issues involving their substations. The list of participants is enclosed at Annexure-I.

Sh. S.R. Bhat, Member Secretary (MS), SRPC welcomed Officials of PED, NLCIL, PGCIL (SR-II) to the

meeting and thanked Sh. D. Ravi, SE-I & HoD of PED for arranging the meeting at short notice. Then,

outlining the reasons for calling special meeting, he stated that 230 kV substation of PED at Villianur is

an important system element in grid operation. However, of late it was seen that there were three grid

disturbances (30th May, 5th June and 15th June 2018) in Villianur S/S affecting all the loads connected to

it. The adverse effect on the load due to the disturbance was to the extent of 100 -120 MW which is

fairly sizeable and is about 35 % of the total demand of PED system.

He informed that in the aftermath of the grid disturbances of 2012, Central Electricity Authority was

keeping a regular watch on the grid disturbances in the country. Periodic reports were also being

submitted to the Ministry of Power. Hence, three grid disturbances in fairly quick succession in PED

system had attracted attention.

Of the three events, the first two were discussed in the 75th meeting of PCSC held on 28.06.2018.

However, owing to absence of PED representatives, these events, which primarily occurred because of

failure of some substation equipment along with non-operation of required protections, could not be

analysed in detail.

He also stated that recognizing the importance of 230/110 kV Villianur and Bahour substations in

supplying power to Puducherry, comprehensive protection audit of the same was conducted by SRPC

teams in July, 2017, and a no. of measures were suggested for system improvement. However, based on

the status furnished by PED, it was noted that not much progress was observed with regard to

implementation of remedial measures.

In view of the gravity of the matter, it was therefore decided to convene this meeting to analyze these

Grid Disturbances in detail, to review the status of implementation protection audit remarks of Villanur

& Bahour substations, and to identify various short-term and long-term measures for time-bound

implementation in the interest of smooth grid operation.


B. Analysis of the Villianur GD’s on 30.05.2018, 05.06.2018 & 15.06.2018

The Grid Disturbances that occurred on 30.05.2018, 05.06.2018 & 15.06.2018 at 230/ 110 kV Villianur

Substation were thoroughly analysed in the meeting. Their analysis, along with necessary measures

required to be taken by various partied involved, is enclosed at Annexure-II for kind reference. The

details of the tripping events including relevant PMU plots presented by SRLDC in the meeting are also

enclosed at Annexure-V for kind reference.

PED, PGCIL (SR-II) and NLCIL were requested to initiate necessary action to comply with the measures

recommended.

C. Review of status of implementation of Protection Audit Recommendations of Villanur and

Bahour Substations.

Subsequent to a similar GD event at 230/ 110 kV Villianur SS on 19.05.2017 (triggering incident in this

case was failure of CT in 110 kV Villianur-Kurumbapet), comprehensive protection audit of 230/ 110 kV

Villinaur SS and 230/ 110 kV Bahour SS was conducted by SRPC teams in July, 2017, and a no. of

recommendations were given for system improvement.

Based on the status furnished by PED vide their mail dated 10.07.2018, implementation status of above

remarks was reviewed in the meeting, and the same is enclosed at

Annexure-III for kind reference. It was noted that even though implementation of majority of the

remarks is linked with PSDF funding, there is a significant chunk of remarks which have no financial

implications, but solely related to revising existing relay settings, and could have been attended by this

time.

PED was therefore asked to attend the latter set of remarks on priority basis in a month’s time. Further,

since various works had already been commenced through PSDF funding, PED was asked to complete the

remaining remarks also in a phased and time-bound manner.

D. Review of compliance status of the recommendations given in the special meeting held on

3rd January, 2017 w.r.t. Neyveli Grid Disturbance on 25.11.2016

In the meeting, the compliance status of the recommendations given in the Special Meeting held on

3rd January, 2017 w.r.t. Neyveli Grid Disturbance on 25.11.2016 was reviewed, and the same is enclosed

at Annexure-IV for kind reference & necessary action by PED, NLCIL & TANTRANSCO.

It was noted that TANTRANSCO representatives had not come to attend the meeting.


E. Measures identified for time-bound implementation of various protection remarks by PED

While appreciating the steps and constraints expressed by PED, the following measures were

highlighted for time bound and focused implementation:

Since the protection systems in place at Villianur & Bahour substations are not in compliance of

various protection standards & regulations, early & time-bound implementation of the ongoing

schemes for renovation and up-gradation of substations through the Power System Development

Fund was emphasized.

In the Review Meeting of PSDF held in January 2018, Chairperson, CEA had expressed concern over

the slow pace of implementation. PED had also been requested to kindly step up the pace of

implementation.

It was noted that PED is in the process of submitting a revised DPR for additional PSDF funding to

undertake further works for improving protection systems at Villianur & Bahour substations.

However, since considerable time had lapsed since the Review Meeting in January 2018, PED was

asked to expedite the same.

It was noted that at present PED is dependent on external agencies for carrying out testing of

various electrical equipment & relays & protection oriented trouble shooting. Similarly,

over-dependence on TANTRANSCO engineers was hampering the works. PED was therefore

requested to initiate steps to suitably develop manpower of PED in various activities such as relay

setting calculations etc. or alternatively, approach central PSU such as POWERGRID, who would

undertake the works on consultancy basis. The necessity of establishing Standard Testing Lab and

procurement of essential testing equipments to cater to all 230 kV substations under PED control

was high-lighted.

PED was asked to ensure regular participation of their Officers in the Sub-Committee Meetings of

SRPC, especially those relating to Protection.

In view of the criticality of Villianur & Bahour substations, PED was also asked to identify a Nodal

Officer at senior level to make periodic assessment of status of implementation of their protection

audit remarks, and take steps to remove any bottlenecks by bringing them to the notice of their

higher management for efficient redressal.

F. Vote of Thanks

MS, SRPC thanked SE-I & HoD, PED and other Officials from Puducherry ED, NLCIL, PGCIL (SR-II) & SRLDC for participating in the Meeting. He hoped that with active co-operation & due diligence by PED, measures as chalked out would be given priority for improving protection systems at Puducherry Substations, and effective monitoring mechanisms would be put in place to improve their operational performance.

*****

Annexure-I

Analysis of Grid Disturbances at Villianur Substation of Puducherry ED 1/8

Analysis of the Villianur GD’s on 30.05.2018, 05.06.2018 & 15.06.2018

Sl. No.

Details of Event Date &Time Reason Remarks Category

1 Complete outage of 230/ 110 kV Villianur Substation

08:40 hrs on 30-05-2018

Triggering incident was failure of 230 kV side R-ph CT of 230/ 110 kV of ICT -2 at 230/ 110 kV Villianur station. 230 kV Neyveli - Villanur and 230 kV Pondy - Villianur lines tripped from Neyvelli end and Pondycherry end respectively. This led to loss of supply to 230 kV Villianur Station.

Load Loss: 130 MW

GD-1

Stipulated TR formats were not used by PED and NLCIL SLD:

The single line diagram of 230/ 110 kV Villianur SS as furnished by PED is attached at the end. Tripping of 230 kV Villianur – NLC-II line: NLC-II (NLCIL) end:

As per FIR/DR/EL/TR, line tripped at 08:50:00.544 hrs due to operation of SOTF O/C protection.

Time-sync of Protection Relays with GPS needed to be ensured at NLC-II. Villanur (PED) end:

As per FIR, the line was kept holding from Villianur end.

It was stated in TR that 230 kV R-ph HV-II CT of 100 MVA Auto Transformer-II failed resulting in tripping of both 230 kV Villanur – NLC2 line and 230 kV Villianur-Pondy line from remote ends. The respective breakers at Villianur 230 KV SS end were holding and only the breakers at Neyveli and Pondy ends got tripped.

Tripping of 230 kV Villanur – Pondicherry line: Pondycherry (PGCIL-SR2) end:

As per FIR/DR/EL/TR, line tripped at 08:42:23.564 hrs due to DPR, Z2 (with Tz2 = 250 msec) operation. Villanur (PED) end:

As per FIR, the line was kept holding from Villianur end.

It was stated in TR that 230 kV R-ph HV-II CT of 100 MVA Auto Transformer-II failed resulting in the tripping of both 230 kV Neyveli - Villanur line and 230 kV Pondy - Villianur line. The respective breakers at Villianur 230 KV SS end was holding and only the breakers at Neyveli and Pondy ends tripped.

Remedial action informed by PED: Failed CT (Year of manufacture:1985, Year of commissioning: 1987) was replaced with R-phase CT

released from 230 kV Pondy-Villianur Line as no spare CT with similar CT ratio 150-300-600-1200/1-1-1-1A was available on hand at Villianur SS. Auto Transformer-II was brought back into service at 01:15hrs on 31.05.2018.

Remaining Y and B-phase CTs of 230KV Pondy Line were released and one set of new CTs with CT ratio 400-800-1000-1200-1600/1-1-1-1A were erected in Pondy line bay on 31.05.2018. After having conducted pre-commissioning tests by P&C wing of TANTRANSCO Limited, Villupuram, 230 kV Pondy-Villianur line was closed at 20:20 hrs on 11.06.2018 and brought the Villianur SS into Grid. However, 230 kV Busbar protection scheme was kept out of service before energizing the Pondy line since CT ratio adopted for Busbar protection to 230 kV Neyveli, HV-I and HV-II (600/1A)

Annexure-II


differed from that of 230KV Pondy Line (1200/1A). Six numbers of new 230 kV CTs with CT ratio 300-600-1000-1200-1600/1-1-1-1A have been

supplied to this department by M/s PGCIL on 04.07.2018 in lieu of CTs borrowed by them. Actions have been initiated to replace the in-service aged 230KV HV-I & HV-II CTs with the newly supplied CTs. After the replacement of CTs, the 230 kV Busbar protection scheme will be brought back into service. P&C wing of TAN TRANSCO Limited, Villupuram has been requested to carry out pre-erection test on the new CTs in order to commence the CT erection work.

Remedial action informed by NLCIL: When enquired about the reasons for SOTF operation at NLCIL end on 230 kV NLC2 – Villianur line,

NLCIL informed that it was due to old setting of SOTF protection (2000 A) implemented from an external relay. As a remedial measure, its setting was now revised to 2800 A.

Deliberations: It was noted that the triggering fault (CT blast) was within zones of differential protection of 230/ 110

kV Autotransformer - II and 230 kV busbar protection. However, non-operation of these primary protections during the incident was suspected/ attributed to the fact that since 110 kV side was radially fed, shorting/ bypassing of the CT from 230 kV side during the incident on account of engulfing arc might have resulted in zero difference current, and their consequent non-operation.

When enquired about the time-line for restoring 230 kV BBP, PED informed that they would be availing shutdowns on 28.07.2018 and 04.08.2018 to complete replacement works of CT’s, hence by the end of first week of August, 2018, they would be able to put 230 kV BBP back into service at Villianur SS. However, considering the frailty of the substation equipment, and the need to avoid delayed clearance of faults during this intermediate time, PGCIL (SR-II) and NLCIL were asked to immediately effect the following changes:

PGCIL (SR-II) to revise Zone-2 time-setting to 150 msec at Pondy end on 230 kV Pondy - Villianur line.

NLCIL to revise Zone-2 time-setting to 150 msec at NLC TS-2 end on 230 kV NLC TS2 - Villianur line.

The above revised settings would be retained till 230 kV Busbar protection is put into service at 230/ 110 kV Villianur SS, which information would be shared by PED with all concerned.

When enquired about why interlock with CB status was not employed for SOTF protection, NLCIL informed that such provision was not available in the external relay. However, after commissioning of Main-II relay in about 6 months time, SOTF protection with CB status interlock would be provided from the same.

In this regard, it was noted that since the same functionality is being provided by the existing O/C & E/F back-up protections of the line from NLC-TS2 end, NLCIL was asked to check if the operating characteristics of SOTF protection implemented from the external relay at NLCIL end on 230 kV NLC TS2 - Villianur line could be changed to IDMT. If so, the same shall be put to use. Else, NLCIL was asked to disable the SOTF protection implemented from the external relay. In the event of disabling SOTF protection, NLCIL was also asked to take steps for providing Main-II relay for the line at the earliest, and implement SOTF protection from it.

In this regard, PED was asked to take steps to comply with the protection audit remarks of 230/ 110 kV Villianur SS in a phased and time-bound manner.

Annexure-II


2 Complete outage of 230/ 110 kV Villianur SS of PED

11:23 hrs on 05-06-2018

Triggering incident was the failure of R-ph breaker of 110 kV Kalappet-Villianur line got failed at Villianur end. Fault was cleared by tripping of the upstream feeders. 230kV NLC St-2 Villianur tripped at NLC end and 230kV Pondy Villianur line tripped at Pondy end on Zone-3 distance operation, resulting in the loss of supply to 230 kV Villianur station.

Load Loss: 120 MW

GD-1

Stipulated TR formats were not used by PED and NLCIL SLD:

The single line diagram of 230/ 110 kV Villianur SS as furnished by PED is attached at the end. Tripping of 230 kV Villanur – NLC-II line: Villianur (PED) end:

As per FIR, line was kept holding. NLC-II (NLCIL) end:

As per FIR/DR/EL/TR, line tripped at 11:23:54.963 hrs due to DEF (Tef =2.15 sec) operation. Tripping of 230 kV Villanur – Pondicherry line: Villianur (PED) end:

As per FIR, line was kept holding. Pondicherry (PGCIL-SR2) end:

As per FIR/DR/EL/TR, line tripped at 11:23:50.052 hrs due to DPR, Z3 operation (observed Tz3 = 0.5 sec).

In the furnished DR & EL, along with Z3_Trip, Z4_Trip was also observed at the same time. As per PED report furnished vide their mail dated 21.06.2018 :

For 110 kV Villianur – Kalapet feeder fault, Main-I distance protection relay of the said feeder picked up the fault, and actuated the trip relay. Due to impact of the fault, B-ph pole column of the breaker failed and hence the feeder breaker failed to open.

HV & LV O/C relays of both Auto-Transformer-I & Auto-Transformer-II acted for R, Y & B phase, but none of the breakers of Auto-Transformers got opened as the terminal fuse of 110 V Station Battery Bank was found to be blown out.

Remedial action informed by PED: Terminal fuse of 110 kV Station Battery Bank was replaced. Cause for the blown out of fuse was

being studied. A work order has been issued to a contractor M/s Ragavi Engineers, Puducherry vide Order

No.05/ED/EE-Auto SS/AEE-M-VASS/2018-19, dated 06.07.2018 at the cost of Rs. 97, 350/- for providing 4 sets of pipe in pipe chemical earthing at the back yard of control room to strengthen the existing earthing of Control & Relay panels, AC & DC Distribution panels and 110 Volt Station and 48 Volt PLCC battery chargers within 15days from the date of work order.

Failed Kalapet feeder breaker (Year of manufacture: 1987, Year of commissioning: 1987) was replaced with new circuit breaker. Also the aged CTS of Kalapet feeder (Year of manufacture: 1986, Year of commissioning: 1987) were also replaced with new CTs as a precautionary measure.

Switch yard earthing was measured during the total shutdown availed in Villianur SS on 30.06.2018. Individual and combined earth pit value of Kalapet feeder bay was observed to be

Annexure-II


3 ohm. However, other earth pit values are observed on higher sides, actions have been initiated to strengthen earthing of switch yard.

Deliberations: It was noted that even though the triggering cause of the GD had to do with the failure of operating

mechanism of the 110 kV CB on 110 kV Villianur – Kalapet line at Villianur end, the main cause for the GD was the failure of 110 kV Protection DC which led to non-opening of the HV and LV breakers of Autotransformers on O/C & E/F protections. Here it was also noted that the claim of PED that O/C & E/F protections had operated but the corresponding HV & LV breakers of Autotransformers – I & II could not be sustained given the fact that same DC was energizing both relays and breakers. Thus, it was suspected that failure of 110 kV protection DC could be due to issues relating to improper earthing of various equipment in the substation, which was also corroborated by the measured high earth-resistance values of various pits.. As informed by PED, since steps had already been initiated in the direction of improving earth-pit resistances, they were also asked to carry out station earth-mat integrity test covering both 230 kV & 110 kV voltage levels.

In this regard, it was also noted that since 110 kV sides of Villianur and Bahour Sations are radially fed, PGCIL (SR-II) and NLCIL were asked to revise Zone-3 timing on 230 kV lines emanating from 230 kV Pondy and 230 kV NLC TS-2 to 0.8 sec as mentioned below:

PGCIL (SR-II) to revise Zone-3 time-setting to 800 msec at Pondy end on 230 kV Pondy - Villianur line & 230 kV Pondy – Bahour line.

NLCIL to revise Zone-3 time-setting to 800 msec at NLC TS-2 end on 230 kV NLC TS2 - Villianur line & 230 kV NLC TS@ - Bahour line.

PGCIL (SR-II) was also asked to examine the reasons for Zone-4 trip, and correct the same. In this regard, PED was also asked to take steps to comply with the protection audit remarks of

Villianur SS in a phased and time-bound manner.

Annexure-II


3

Complete outage of 230/ 110 kV Villianur SS of PED

07:29 hrs on 15-06-2018

Triggering event was failure of B-phase 230 kV Current Transformer (Make: TELK) of HV-I Breaker of 230/110 kV 100 MVA Auto Transformer-I at Villianur substation. Fault was cleared by tripping of source feeders i.e. 230 kV Neyveli-Villianur Line breaker at NLC TS-II and 230KV Pondy-Villianur Line Breaker at 400KV Pondy S/S. Fault was cleared in 350 ms as observed from PMU data plot. This in-turn resulted in loss of supply to 230 kV Villinanur station.

Load Loss: 102 MW

GD-1

Stipulated TR formats were not used by PED and NLCIL Tripping of 230 kV Villanur – NLC-II line: Villianur (PED) end:

As per FIR/TR, line was kept holding.

It was stated in FIR/TR that Failure of B-phase 230KV Current Transformer (Make: TELK, Sl. No.:230116-39, Year of Manufacture: 1985) of HV-I Breaker of 230/110 kV 100MVA Auto Transformer-I at 07:29 hrs on 15.06.2018 due to ageing, resulted in tripping of 230 kV Neyveli-Villianur Line breaker at TS-II, Neyveli and 230 kV Pondy-Villianur Line Breaker at 400 kV Pondy SS. Due to this, supply to 110/ 22 kV substations, viz., Marapalam SS, Venkata Nagar SS, Kalapet SS, and Villianur SS fed from this station got affected.

NLC-II (NLCIL) end:

As per FIR, line tripped at 07:29 hrs due to DPR operation. (Type of fault and type of protection operated were not mentioned).

TR not furnished (In place of TR, EL furnished.)

As per EL, line tripped (in 3-ph) at 07:29:50.522 hrs on Relay Definitive Trip/ 86T operation.

As per DR, line tripped (in 3-ph) at 07:29:50.522 hrs on 86T operation.

Time-sync of PR’s with GPS needed to be ensured. Tripping of 230 kV Villanur – Pondicherry line: Villianur (PED) end:

As per FIR/TR, line was kept holding.

It was stated in FIR/TR that Failure of B-phase 230KV Current Transformer (Make: TELK, Sl. No.:230116-39, Year of Manufacture: 1985) of HV-I Breaker of 230/110 kV 100MVA Auto Transformer-I at 07:29 hrs on 15.06.2018 due to ageing, resulted in tripping of 230 kV Neyveli-Villianur Line breaker at TS-II, Neyveli and 230 kV Pondy-Villianur Line Breaker at 400 kV Pondy SS. Due to this, supply to 110/ 22 kV substations, viz., Marapalam SS, Venkata Nagar SS, Kalapet SS, and Villianur SS fed from this station got affected.

Pondicherry (PGCIL-SR2) end:

As per FIR/DR/EL/TR, line tripped at 07:29:25.733 hrs on B-E fault due to DPR, Z2 (tz2 = 250 msec) operation.

Remedial action informed by PED: Failed CT (Year of manufacture: 1985, Year of commissioning:1987) was replaced with Y-phase CT

released from 230 kV Pondy-Villianur Line as no spare CT with similar CT ratio 150-300-600-1200/ 1-1-1-1A was available on hand at Villianur SS. Auto Transformer-I was brought back into service at

Annexure-II


19:31 hrs on 15.06.2018. Six numbers of new 230 kV CTs with CT ratio 300-600-1000-1200-1600/1-1-1-1A have been

supplied to this department by M/s PGCIL on 04.07.2018 in lieu of CTs borrowed by them. Actions have been initiated to replace the in-service aged 230KV HV-I & HV-II CTs with the newly supplied CTs to avoid any more failure of 230KV CTs due to ageing.

Deliberations: It was noted that the triggering fault (CT blast) was within the zone of differential protection of 230/

110 kV Autotransformer – I (230 kV BBP had been kept out of service at the time of occurrence of this GD). However, non-operation of these primary protections during the incident was suspected/ attributed to the fact that since 110 kV side was radially fed, shorting/ bypassing of the CT from 230 kV side during the incident on account of engulfing arc might have resulted in zero difference current, and their consequent non-operation.

When enquired about the time-line for restoring 230 kV BBP, PED informed that they would be availing shutdowns on 28.07.2018 and 04.08.2018 to complete replacement works of CT’s, hence by the end of first week of August, 2018, they would be able to put 230 kV BBP back into service at Villianur SS. However, considering the frailty of the substation equipment, and the need to avoid delayed clearance of faults during this intermediate time, PGCIL (SR-II) and NLCIL were asked to immediately effect the following changes:

PGCIL (SR-II) to revise Zone-2 time-setting to 150 msec at Pondy end on 230 kV Pondy - Villianur line.

NLCIL to revise Zone-2 time-setting to 150 msec at NLC TS-2 end on 230 kV NLC TS2 - Villianur line.

The above revised settings would be retained till 230 kV Busbar protection is put into service at 230/ 110 kV Villianur SS, which information would be shared by PED with all concerned.

When enquired about the type of protection that resulted in 86T operation from NLC TS2 end, NLCIL informed that they would look into the same and revert soon. Since the protection had acted almost instantaneously, NLCIL was asked to take necessary steps to rectify the same and inform the remedial action taken.

In this regard, PED was also asked to take steps to comply with the protection audit remarks of Villianur SS in a phased and time-bound manner.

Annexure-II


Single line diagram of 230/ 110 kV Villianur SS of Puducherry ED (Ref: 1)

Annexure-II


Single line diagram of 230/ 110 kV Villianur SS of Puducherry ED (Ref: 2)

Annexure-II

Sl. No. Status of Implementation of Protection Audit Recommendations Remarks

1 Mail dated 30.01.2018 & 13.03.2018 & 10.07.2018:

Existing Control & Relay Panels installed with static relays are proposed to be replaced with new control panels

installed with numerical relays under the project of Upgradation of existing static relays and replacement of sub-

station equipments at 230KV Villianur and Bahour Auto Sub-Station at the cost of Rs.10,56,16,191/- through

PSDF funding. Tendering process for award of work on labour contract basis for the above said work is almost

over and waiting for the approval of Puducherry Government to place order at the lowest tenderer.

Pending PSDF

2 Mail dated 30.01.2018 & 13.03.2018:

As per the recommendation of Protection Audit Team, a Detailed Project Report at the cost of

Rs.14,85,42,653.21 has been prepared to replace the existing aged equipments and provide additional

equipments at 230KV Villianur and Bahour Auto Sub-Station and sent to higher authority to obtain sanction under

PSDF funding. (copy enclosed)

Mail dated 10.07.2018:

A tender has been floated on 15.05.2018 to invite e-tender to replace the existing aged outdoor equipments

along with deteriorated RCC supporting structure. Provision has been given to provide Line CVTs in all phases in

the fore said tender. The e-tender has been opened and Technical evaluation is under process.

Pending PSDF

3 Mail dated 30.01.2018 & 13.03.2018:

Existing aged Two sets of 110Volt Station Batteries have been replaced with two sets of new 110Volt Station

Batteries. Further, in addition to the existing one set of 48Volt PLCC battery, one more 48Volt PLCC Battery has

been provided. All the above three batteries have been commissioned in the last week of January 2018. Wiring

has to be done to segregate the existing single circuit into two circuits.

Pending

4 Mail dated 30.01.2018 & 13.03.2018:






Pending PSDF

5 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Protection & Communication wing of TAN TRANSCO Limited, Villupuram has been requested vide Lr.

No.347/ED/EE-Auto SS/AEE-M-VASS/F-4/2017-18, dated 21.09.2017 for revision of existing relay settings as per

the recommendations of Protection Audit Team.

Pending Settings

6 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

Deficiences/Nonconformity observed

Redundant DC suppy for protection (110 V) and communication (48 V)

applications to be provided with requisite segregation in wiring.

For 230 kV feeders, the present single-zone BB protection is to be reviewed and

provided with two-zone operation & Check-zone operation.

Z4 (reverse) is to be provided in all distance relays of 230 kV & 110 kV feeders

Z2 and Z3 (reactive & resistive) reaches & time settings were observed to be

not in line with Ramakrishna Committee guidelines, which may be reviewed

appropriately.

Puducherry ED

1) 230/ 110 kV Villianur SS [10 - 12 July, 2017]

Status of Implementation of New Protection Audit Recommendations (as on 20.07.2018)

Directional O/C & E/F protections to be provided for 230 kV & 110 kV feeders

where Main-II is not provided; Directional E/F protection to be provided for 230

kV & 110 kV feedes where Main-I & Main-II are provided

Line CVT's to be provided in all phases for all 230 kV lines.

1/11

Annexure-III

Page 1 of 11

7 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

8 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

9 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

10 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

11 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:





Pending

12 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

13 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

14 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

Steps to be taken to ensure that Main-I & Main-II protections or Main & back-up

protections of feeders are fed from different DC supplies.

REF protection to be provided for 100 MVA, 230/ 110 kV ICT-1 & ICT-2.

Directionality to be provided for O/C protection of 100 MVA, 230/ 110 kV ICT-1

& ICT-2.

Directional E/F protection to be provided for 100 MVA, 230/ 110 kV ICT-1 & ICT-

2.

Power Swing Philosophy (Z1 --> Unblock; Higher Zones --> Block for 2 sec) is

to be adoped unfiromly across all 230 kV feeders.

Load encroachment feature may be appropriately kept enabled in 230 kV & 110

kV feeders.

For 230 kV Pondy feeder POR may be used in place of the existing PUR.

Auto-reclosure dead-time and reclaim-time for 230 kV feeders may be revised to

1 sec and 25 sec respectively.

2/11

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Page 2 of 11

15 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

16 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:





Pending

17 Mail dated 30.01.2018:

Various possible ways to connect the 110/22KV Villianur Sub-Station with nearby 110/22KV Korkadu SS by 22KV

feeder is being explored.

Mail dated 13.03.2018 & 10.07.2018:

Division-EHV of this department has been requested vide Lr. No.714/Ed/EE-Auto SS/AEE-M-VASS/F-4/2017-18,

dated 27.02.2018 (Copy enclosed) to explore the possibilities of providing another 200KVA, 22KV/440V station

transformer I nearby 110/22KV Villianur SS that is charged by a 22KV feeder either from 110/22KV Korkadu SS

or Kurumbapet SS for providing AC auxiliary supply to 230KV Villianur Auto SS.

Pending

18 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

19 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

20 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

21 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




PSDF funding. (copy enclosed)

Pending PSDFIt was observed that existing 100 MVA transformers had not been provided with

fire protection. Steps may be taken to provide the same in accordance with the

relevant standards.

Steps to be taken to ensure that Group-A & Group-B protections or Main & back-

up protections of ICT's are fed from different DC supplies.

Steps may be to taken provide DR's with facility for automatic fault record

downloading to a central PC/ server.

Standalone Event Logger may be provided.

Overflux protection to be provided for 100 MVA, 230/ 110 kV ICT-1 & ICT-2.

At present AC auxiliary supply is being provided from 440 Volt, 3phase, 50 Hz

LT supply from 200 kVA, 22 kV/440 V Transformer connected directly on the

main bus of the nearby 110/22 kV Villianur SS. Since this substation is fed from

230/ 110 kV Villianur substation, steps may be taken to provide redundant AC

auxiliary supply by providing another 200 kVA, 22 kV/ 440 V transformer in the

110/ 22 kV SS that is charged from 22 kV Korkadu feeder, and laying another

440 V cable from its secondary to thr AC supply changeover panel at 230/ 110

kV Villianur SS.

GPS based time-synchronization equipment may be provided for synchronizing

various 230 kV & 110 kV protection relays.

3/11

Annexure-III

Page 3 of 11

22 Mail dated 30.01.2018 & 13.03.2018:




PSDF funding. (copy enclosed). In that DPR, replacement of existing deteriorated RCC supporting structures have

been proposed to be replaced with G.I. lattice structure.




the fore said tender.

Pending PED

23 Mail dated 30.01.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to provide chemically treated PCC flooring,

and then covering it with suitable blue metal spreading in switchyard area.

Mail dated 13.03.2018 & 10.07.2018:

Vegetation & weeds grown in the switch yard area were manually cleared and now the switch yard is kept clean.

However, as a permanent measure, Detailed Project Report at the cost of Rs.14,85,42,653.21 has been prepared

to replace the existing aged equipments and provide additional equipments at 230KV Villianur and Bahour Auto

Sub-Station and sent to higher authority to obtain sanction under PSDF funding. (copy enclosed). In that DPR,

provision has been given to provide chemically treated PCC flooring, and then covering it with suitable blue metal

spreading in switchyard area.

Pending PSDF

24 Mail dated 30.01.2018 & 13.03.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to replace the existing dilapidated gantry &

equipment supporting (RCC) structures with G.I. lattice / tubular structures.




the fore said tender

Pending PSDF

25 Mail dated 30.01.2018 & 13.03.2018:

Action has been initiated to bring down the earth resistance value to less than 1ohm


Earth resistance values have been measured in the last total shutdown availed in this station on 30.06.2018.

Action has been initiated to bring down the earth resistance value to less than 1ohm

Pending

26 Mail dated 30.01.2018:

Action has been initiated to Equipment labeling for proper phase-sequence

Mail dated 13.03.2018 & 10.07.2018:

The work of Equipment labeling for proper phase-sequence was completed on 13.03.2018.

compliedEquipment labeling for proper phase-sequence may be provided.

It was observed that supporting structures and equipment such as breakers,

CT's, isolators, etc. In 110 kV switchyard had served thier full life. Steps may be

taken to refurbishing of 110 kV switchyard appropriately.

Vegetation & weeding was observed in switchyard area. Steps may be taken to

provide chemically treated PCC flooring, and then covering it with suitable blue

metal spreading in switchyard area.

It was observed that most of the existing gantry & equipment supporting (RCC)

structures are in dilapidated state. Steps may be taken to replace them with

suitable lattice/ tubular structures.

Earth-resistance values for various earth-pits seem to be on higher side. Steps

may be taken to bring it down to less than 1 ohm.

4/11

Annexure-III

Page 4 of 11

27 Mail dated 30.01.2018:

Action has been initiated for Earthing of equipment including door-to-panel earthing.

Mail dated 13.03.2018 & 10.07.2018:

The work of Earthing of various equipment including door-to-panel earthing was completed on 13.03.2018.

Complied

28 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Suitable canopy has been fabricated and kept on hand awaiting for shutdown to provide over Buchholz relays

Pending

29 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Steps have been initiated to establish Standard Testing Lab and procurement of essential testing equipments to

cater to all 230 kV substations.

Pending

30 Mail dated 30.01.2018:

Detailed scope of the works included in proposed R & U works has already been furnished vide Lr.256/ED/EE-

MRT&MMC/F-SRPC/2017-18, dated 14.08.2017. (copy enclosed)

Mail dated 13.03.2018 & 10.07.2018:



Complied

31 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

Sl. No. Status of Implementation of Protection Audit Recommendations Remarks

1 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

2 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Control & Relay Panels installed with static relays are proposed to be replaced with new control panels installed

with numerical relays under the project of Upgradation of existing static relays and replacement of sub-station

equipments at 230KV Villianur and Bahour Auto Sub-Station at the cost of Rs.10,56,16,191/- through PSDF

funding. Tendering process for award of work on labour contract basis for the above said work is almost over

and waiting for the approval of Puducherry Government to place order at the lowest tenderer.

Pending PSDFDirectional O/C & E/F protections to be provided for 230 kV & 110 kV feeders

where Main-II is not provided; Directional E/F protection to be provided for 230

kV & 110 kV feedes where Main-I & Main-II are provided

In view of radial operation of 110 kV feeders, Zone-1 reach may be increased to

90 % of line length, and Zone-2 time-setting may be reduced to 150 msec.

2) 230/ 110 kV Bahour SS [10 - 12 July, 2017]

Deficiences/Nonconformity observed

It is observed that main protections of feeders (230 kV as well as 110 kV) and

trasformers are being provided from static relays. Steps may be taken to replace

the same with suitable numerical relays.

Earthing of various equipment including door-to-panel earthing to be properly

ensured.

Buccholtz relays may be provided with suitable canopy to prevent unwarranted

trippings due to moisture ingress.

At present, PED is dependent on external agencies for carrying out testing of

various electrical equipment & relays & protection oriented trouble shooting.

Steps may be taken to establish Standard Testing Lab and procurement of

essential testing equipments to cater to all 230 kV substations under its control.

PED informed that they had already initiated steps for Renovation & Upgradation

(R&U) of grid stations in Pondycherry region (230/ 110 kV Villianur SS & 230/

110 kV Bahour SS) under PSDF funding, covering most of the above works. In

this regard, PED is requested to furnish detailed scope of the works included in

proposed R & U works.

5/11

Annexure-III

Page 5 of 11

3 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

4 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

5 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

6 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

7 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

8 Mail dated 30.01.2018 & 13-03-2018 & 10.07.2018

Co-ordination of Protection & Communication wing of TAN TRANSCO Limited, Villupuram has been requested to

bring the 230KV and 110KV Bus Bar Protection scheme into service.

Pending

9 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




Pending Settings

10 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

One set of existing aged 110Volt Station Battery has been replaced with a new battery bank during the last week

of January 2018. Action has been initiated for necessary wiring to segregate Main-I and Main-II Protection to fed

from different DC source.

Pending

11 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

Load encroachment feature may be appropriately kept enabled in 230 kV & 110

kV feeders.

It is observed that busbar protection relays have been provided for both 230 kV

& 110 kV buses. However, the same have been kept out of service since

commisssioning. PED shall take steps to put these into operation.

For 230 kV Pondy feeder POR may be used in place of the existing PUR.

Steps to be taken to ensure that Main-I & Main-II protections or Main & back-up

protections of feeders are fed from different DC supplies.

REF protection to be provided for 80 MVA, 230/ 110 kV Transformers -1 & 2.

Z4 (reverse) is to be provided in all distance relays of 230 kV & 110 kV feeders

Z2 and Z3 (reactive & resistive) reaches & time settings were observed to be

not in line with Ramakrishna Committee guidelines, which may be reviewed

appropriately.

Auto-reclosure dead-time and reclaim-time for 230 kV feeders may be revised to

1 sec and 25 sec respectively. Accordingly Pole Discreancy time-delay may be

kept at 1.5 sec.

Power Swing Philosophy (Z1 --> Unblock; Higher Zones --> Block for 2 sec) is

to be adoped unfiromly across all 230 kV feeders.

6/11

Annexure-III

Page 6 of 11

12 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

13 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

14 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

15 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

One set of existing aged 110Volt Station Battery has been replaced with a new battery bank during the last week

of January 2018. Action has been initiated for necessary wiring to segregate Group-A and Group-B Protection of

Transformer fed from different DC source.

Pending

16 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

17 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

18 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:






Pending PSDF

Steps may be to taken provide DR's with facility for automatic fault record

downloading to a central PC/ server.

Stand-alone Event Logger may be provided.

Directionality to be provided for O/C protection of 80 MVA, 230/ 110 kV

Transformers -1 & 2.

Directional E/F protection to be provided for 80 MVA, 230/ 110 kV Transformers

-1 & 2.

Overflux protection to be provided for 80 MVA, 230/ 110 kV Transformers -1 &

2.

Steps to be taken to ensure that Group-A & Group-B protections or Main & back-

up protections of Transformers are fed from different DC supplies.

GPS based time-synchronization equipment may be provided for time-

synchronizing various 230 kV & 110 kV protection relays.

7/11

Annexure-III

Page 7 of 11

19 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to provide Line CVTs in all phases for all

230KV Lines..

Pending PSDF

20 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to provide Surge Arrestors for 230KV

feeders at gantry entry point.

Pending PSDF

21 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Budgetary offer has been called for from a reputed contractor for arresting oil leakage observed in the

Transformers. Work will be commenced shortly on obtaining expenditure sanction from the competent authority

on the estimate prepared with the rate offered by the contractor.

Pending PED

22 Mail dated 30.01.2018 & 13-03-2018:

the recommendation of Protection Audit Team, a Detailed Project Report at the cost of Rs.14,85,42,653.21 has

been prepared to replace the existing aged equipments and provide additional equipments at 230KV Villianur and

Bahour Auto Sub-Station and sent to higher authority to obtain sanction under PSDF funding. (copy enclosed). In

that DPR, provision has been given to provide fire protection system to 80MVA Auto Transformer-I&II.





PSDF funding. (copy enclosed). In that DPR, provision has been given to provide fire protection to transformers.

Pending PSDF

23 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

OEM M/s.Crompton Greaves Limited has been requested to offer rate to bring back the 230KV Bus Coupler

Breaker into service. As per the recommendation of Protection Audit Team, a Detailed Project Report at the cost

of Rs.14,85,42,653.21 has been prepared to replace the existing aged equipments and provide additional


PSDF funding. (copy enclosed). In that DPR, provision has been given to provide attendant CTs to make way to

two-zone busbar protection.

Pending PSDF

24 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Action has been initiated to segregate the wiring for extending supply from DC1 and DC2 to trip coil of 230KV

and 110KV Breakers.

Pending

It is observed that existing 80 MVA transformers have not been provided with

fire protection. Steps may be taken to provide the same in accordance with

relevant standards.

It is observed that 230 kV & 110 kV Bus-Coupler breakers are not in working

condition, and have been kept out of service. Also they have no attendant CT's.

PED may therefore take steps to replace them with attendant CT's to make way

for two-zone busbar protection.

Segregation in wiring for extending supply from DC1 and DC2 to trip coils of 230

kV & 110 kV feeders to be carried out.

Line CVT's to be provided in all phases for all 230 kV lines.

Surge Arrestors to be to be provided for 230 kV feeders at gantry entry point.

Oil leakage is being observed in both 80 MVA, 230/ 110 kV Tranformers.

Suitable action may be taken to arrest the same.

8/11

Annexure-III

Page 8 of 11

25 Mail dated 30.01.2018:

In addition to the existing 48Volt PLCC battery, one more 48Volt PLCC Battery bank has been erected and

commissioned during the last week of January 2018. Wiring will be done to segregate Source-1 & II.

Mail dated 13.03.2018 & 10.07.2018:

In addition to the existing 48Volt PLCC battery, one more 48Volt PLCC Battery bank has been erected and

commissioned as a redundant DC supply for communication during the last week of January 2018 with requisite

segregation in wiring.

Complied

26 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Action has been initiated to earth all gantry towers (metallic structures) including lightning mast.

Pending

27 Mail dated 30.01.2018:

Action has been initiated to Equipment labeling for proper phase-sequence

Mail dated 13.03.2018 & 10.07.2018:

The work of Equipment labeling for proper phase-sequence was completed on 13.03.2018.

complied

28 Mail dated 30.01.2018:

Action has been initiated for Earthing of equipment including door-to-panel earthing.

Mail dated 13.03.2018 & 10.07.2018:

The work of Door-to-panel earthing in various switchyard marshalling panels was completed on 13.03.2018.

complied

29 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Suitable canopy has been fabricated and kept on hand awaiting for shutdown to provide over Buchholz relays

Pending

30 Mail dated 30.01.2018:

Exploring all the possible ways to provide another dedicated redundant AC auxiliary supply from nearby

110/22KV Sub-Station which is being fed by other 230KV Sub-Stations.

Mail dated 13.03.2018 & 10.07.2018:

Division-EHV of this department has been requested vide Lr. No.714/Ed/EE-Auto SS/AEE-M-VASS/F-4/2017-18,

dated 27.02.2018 (Copy enclosed) to explore the possibilities of arranging an alternate 22KV supply fed from

110/22KV Sub-Stations those are either fed from 230KV Villianur Auto SS or 230KV Thondamanatham Auto SS for

the existing 22KV/440V Distribution Transformer installed in the campus of 230KV Bahour Auto SS, presently

being fed by 22KV Pandasozhannlur feeder from 110/22KV Bahour SS.

Pending

31 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

DC earth leakage being observed in the battery charger will be attended in the forthcoming total shutdown.

Replacement of existing DC Distribution Panels have been included in the DPR.

Pending

Equipment labeling for proper phase-sequence may be provided.

Door-to-panel earthing in various switchyard marshalling panels to be properly

ensured.

Buccholtz relays may be provided with suitable canopy to prevent unwarranted

trippings due to moisture ingress.

At present AC auxiliary supply is being obtained from 22 kV Bahour

(Pandasozhanallur) feeder from nearby 110/ 22 kV Bahour SS. Since this 110/

22 kV SS is being fed from the present 230/ 110 kV SS, in the event of supply

failure at the latter, the former will also lose supply. PED shall take steps to

provide another dedicated redundant AC auxiliary supply feeder.

DC earth leakage is being observed in both 110 V DC Sources. Also the

corresponding DC Earth-fault relays in soruce end DCDB panels are observed to

be not in working-condition. Steps shall be taken to rectify the same at the

earliest.

Redundant DC suppy for communication (48 V) application to be provided with

requisite segregation in wiring.

All gantry towers (metallic structures) including lightning masts to be earthed

properly as per relevant standards.

9/11

Annexure-III

Page 9 of 11

32 Mail dated 30.01.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to provide chemically treated PCC flooring,

and then covering it with suitable blue metal spreading in switchyard area.

Mail dated 13.03.2018 & 10.07.2018:

Vegetation & weeds grown in the switch yard area were manually cleared and now the switch yard is kept clean.

However, as a permanent measure, Detailed Project Report at the cost of Rs.14,85,42,653.21 has been prepared

to replace the existing aged equipments and provide additional equipments at 230KV Villianur and Bahour Auto

Sub-Station and sent to higher authority to obtain sanction under PSDF funding. (copy enclosed). In that DPR,

provision has been given to provide chemically treated PCC flooring, and then covering it with suitable blue metal

spreading in switchyard area.

Pending PSDF

33 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:




PSDF funding. (copy enclosed). In that DPR, provision has been given to replace the existing dilapidated gantry &

equipment supporting (RCC) structures with G.I. lattice / tubular structures.

Pending PSDF

34 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Actions have been initiated for Testing of various relays and measurement of earth-resistance values for various

earth-pits periodically as per relevant standards and record them properly

Pending

35 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Protection and Communication wing of TAN TRANSCO Limited, Villupuram has been requested to furnish the

existing relay settings for future reference.

Pending Settings

36 Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Steps have been initiated to establish Standard Testing Lab and procurement of essential testing equipments to

cater to all 230 kV substations.

Pending PED

37 Mail dated 30.01.2018:



Mail dated 13.03.2018 & 10.07.2018:



Complied

Settings

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Fault level of the station has been requested from EHV division of this department. Details will be furnished as

soon as received from the said division.

38 Pending

PED informed that they had already initiated steps for Renovation & Upgradation

(R&U) of grid stations in Pondycherry region (230/ 110 kV Villianur SS & 230/

110 kV Bahour SS) under PSDF funding, covering relay & control panel

replacement works. In this regard, PED is requested to furnish detailed scope of

the works included in proposed R & U works for the 230/ 110 kV substation.

PED has not provided the following data as part of protection audit:

(i) Fault level of the Substation for 3-ph-Ground and 1-ph-Ground faults at both

230 kV and 110 kV levels

Vegetation & weeding is observed in switchyard area. Steps may be taken to

provide chemically treated PCC flooring, and then covering it with suitable blue

metal spreading in switchyard area.

It is observed that most of the existing gantry & equipment supporting

structures have been of RCC. PED may take steps to replace them with suitable

lattice/ tubular structures when R & M works for the substation are propsoed.

Testing of various relays and measurement of earth-resistance values for

various earth-pits should be undertaken periodically as per relevant standards,

and records properly maintained.

It is observed that relay settings for various protection relays have been set by

TNEB at the time of commissioning. However, records relating to the same have

not been made available to PED. Steps may be taken (by PED/ TNEB) to

maintain proper records w.r.t. Implemented relay settings at Substation level.

At present, PED is dependent on external agencies for carrying out testing of

various electrical equipment & relays & protection oriented trouble shooting.

Steps may be taken to establish Standard Testing Lab and procurement of

essential testing equipments to cater to all 230 kV substations under its control.

10/11

Annexure-III

Page 10 of 11

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Protection and Communication wing of TAN TRANSCO Limited, Villupuram has been requested to furnish the

existing relay settings. Relay settings will be furnished as soon as received from the said corporation.

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Details are being collected from the source available at 230KV Bahour Auto Sub-Station. Details will be furnished

shortly.

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Action has been initiated to measure the Earth-mats and Earth-Pits value. Measurements will be submitted

shortly.

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Will be submitted shortly.

Mail dated 30.01.2018, 13.03.2018 & 10.07.2018:

Details have been called for from TAN TRANSCO Limited. Will be submitted shortly on receipt of the same.

(iv) Details of Measurement of Station Earth-Mat & Earth-Pits

(v) AC Supply Changeover Scheme

(vi) Details of 110 kV CT's Ratios and Errors

(ii) Adopted Relay Settings (given by Head Quarters/ Corporate Office and

implemented in field)

(iii) Details on Periodicity of Relay Testing and latest Relay Test Reports

11/11

Annexure-III

Page 11 of 11

Compliance Status of the Recommendations given in the Special Meeting on Neyveli GD held on 03.01.2017

Sl. No.

Recommendation Puducherry ED (furnished vide their mail dated 10.07.2018)

NLCIL (furnished vide their mail dated 13.10.2018)

TANTRANSCO (furnished vide their mail dated

23.02.2017)

1 Provision of GPS/ Time synchronization facility in all 220 kV & above substations/ generation switchyards [PED, TANTRANSCO, NLCIL, ST-CMS]

1. Existing Control & Relay panels installed with static relays are proposed to be replaced with new control panels installed with numerical relays under the project of PSDF in both 230KV Villianur and Bahour Auto Sub-Stations. Tendering process for award of work on labour contract basis for the above work is almost over and awaiting for the approval of Puducherry Government to place order to the lowest tenderer.

2. A tender has been floated on 15.05.2018 to invite e-tender to replace the existing aged outdoor equipments along with deteriorated RCC supporting structure in the above said substations. The e-tender was opened and Technical evaluation is under process.

3. In the event of completion of the above said works, both of the substations would be equipped with GPS / time synchronization facility. [PENDING]

In order to provide GPS connectivity to numerical relays of Generator and feeder, OEM of relay and probable suppliers were addressed. M!s. ABB, OEM of GRP relays, after exten sive fi eld study informed that Time Synchronisation facility is not possible fo r the old version relays in service at TPS-1. TPS 1 is likely to be phased out within a year. All the connected 220KV feeders emanating from TPS 1 Switchyard will be diverted to the upcoming TANGEDCO 230/ 110 KV SS near NNTPP. In view of the above and considering the remaining life period of TPS 1 , the proposal to implement GPS connectivity is under scrutiny for in principle approval. However, built-in clocks of 220KV feeder protection relays are being updated periodically, using a Laptop whose system clock is set to GPS time. Considering the phasing out proposal of TPS 1 from April 2019, 220KV feeders at TPS 1 may be exempted from implement at ion of GPS time synchronisation facility. [PENDING w.r.t. NLC TS2]

Tender has been opened for provision of GPS, DR & EL and procurement is under progress. [PENDING]

Annexure-IV

Page 1 of 5

2 TANTRANSCO was recommended to get the functionality (including power supply) of the DCPC’s [between MLDC and Tiruvannamalai/ Villupuram/ NLC TS-I/ ST-CMS] checked and ensure their healthiness all the time. [TANTRANSCO]

The Digital Events (Breaker status) is programmed for RTU time stamping and the same was tested in Alundur and Trichy 230 kV Sub-Stations. [PENDING] During the tripping of the generation Unit-B on 25-11-2016 (17:27:09 hrs) in O/C protection and subsequent tota l generations/ feeder tripping, the 4BV, BOA Carrier Communication charger AC fuse failed (maintained by NLC) and 4BV, 100Ah battery source drained due to aging (DoC of Battery was 1996 & served for more than 20 years) and all Voice & data channels through PLCC equipments at Neyveli TS-I, (Viz., Cuddalore, T.V.Malai and Villupuram and ST_CMS PLCC in TS-I & II link feeder) disturbed and no data migration from their respective RTUs to DCPC equipment reporting to MLDC Chennai. It is also noted that there is no redundant OFC path ready for data migration to Back-up Control Center at Madurai LDC through Kadalangudi, Thiruvarur towards Trichy provided by PGCIL/Tejas Ltd. under fiber expansion project for ULDC scheme. However as per the ULDC up-gradation scheme, data through Neyveli DCPC (Main & Stand-by) are configured in such a

3 Migrating to RTU time-stamped SoE at the stated stations/substations [Bahour, Villianur, NLC TS-II, NLC TS-I, ST-CMS, Alundur, Trichy, Tiruvannamalai, Villupram, Singarapet and Deviakurichi] [PED, TANTRANSCO, NLCIL, PGCIL (SR-II)]

[PENDING] [PENDING]

Annexure-IV

Page 2 of 5

way to report to MLDC SCADA at Chennai. M/s.PGCIL/Tejas Ltd. will be informed to test and commission the OFC link between Neyveli and Trichy through Kadalangudi, Thiruvarur,Thanjavur & Trichy to extend the communication channel for ULDC SCADA Back-up Control Center at Madurai. [PENDING]

4 Review settings adopted for O/C protection and other relevant protections for Unit-8. [NLCIL]

Reviewed [COMPLIED]

5 NLCIL was recommended to check integrity of Static Excitation System of Unit-1 for proper operation. OEM’s help may also be taken in this regard, if required. [NLCIL]

Settings recommended by M/s BHEL-EDN (OEM), are adopted for Static Excitation System in all the 9 Units of TPS 1. [COMPLIED]

6 Review of AVR’s excitation limiter settings of all generating Units appropriately at NLC TS-I so that unwarranted tripping of generating Units is prevented in fit-cases where GT/ ICT/ feeder O/C protections could have acted first. OEM’s help may also be taken in this regard,

In order to ascertain the integrity of SES of UNIT-1, a committee with three senior executives of NLCIL was constituted. The committee scrutinised the SES settings in all aspects and conducted necessary field tests. OEM was also consulted during the study. The committee has stated that the adopted settings are intact. [COMPLIED]

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if required. [NLCIL]

7 Puducherry was recommended to take appropriate steps for attending to suspected hot-spots in time, which is also mandated as per Regulation 26 of CEA (Grid Standards) Regulations, 2010. [PED]

Total shutdowns are being availed periodically at 230KV substations in Puducherry Electricity Department and carried out maintenance works to avoid any breakdown due to hot-spots. [COMPLIED]

8 TANTRANSCO was recommended to provide at least one more thermo-vision scanning camera so that each circle would have their exclusive thermo-vision scanning camera to attend to hot-spots in time. [TANTRANSCO]

Procurement of Thermo-vision Camera is under progress. [PENDING]

9 Puducherry was recommended to carry out load-rearrangement by shifting some loads from Bahour/ Villianur to Thondamanatham and distribute them more evenly across these substations. [PED]

Load to the tune of 67 MW being so for availed from 230 kV Villianur Auto Sub-Station by 110/22 kV Kurumbapet Substation was transferred to 230KV Thondamanatham SS on 13.04.2018. Now, load at all three 230KV substations are at evenly distributed. [COMPLIED]

10 TANTRANSCO was recommended to undertake holistic review of all such lines, which are mostly kept

open (like Acharapakkam –

It is prudent to maintain the open condition of Acharapakkam Villupuram feeder to avoid the tripp ing of 230 KV Maps - Achrapakkam feeder on overloading. Otherwise if

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Villupurram, Alundur –

Algarkoil, Kadalangudi – Tiruvaroor) for suitable system strengthening measures, and implement them in a phased manner in the interest of grid security and operational flexibility. [TANTRANSCO]

the feeder is tripped, 230 KV MAPS - Echur, SPDR - Arni & MAPS - S.P.Koil # 1 & 2 feeders trip cascadingly on overload. Also, MAPS units will pull out, the cascade disturbance would have been imparted to certain areas of Chennai city i.e. S.P.Koil, Oragadam, Siruseri & Arni. Similarly, the open condition of Alundur - Alagarkoil feeder have saved the cascaded tripping in Madurai, Pugalur and Myvadi areas during the recent disturbance. [COMPLIED] However, review will be done in a phased manner for suitable system strengthening measures for ensuring Grid security. [PENDING]

11 Furnishing of tripping details in compliance of Regulation 5.2 (r) of IEGC [PED, TANTRANSCO, NLCIL, PGCIL (SR-II)]

Tripping events are being uploaded by Puducherry Electricity Department in SRLDC’s web-portal within 24hours of occurrence. [COMPLIED]

COMPLIED [COMPLIED]

The Tripping details are being furnished then and there in the POSOCO website. [COMPLIED]

*****

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Special Meeting on Pending Protection Issues of Puducherry

Substations

20-07-2018

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• Failure of switchyard equipment leading to complete station outage

• Delayed clearance of fault

• Non operation of primary protection at Villianur station

• Load Loss in Pondicherry control area > 100MW (each time)

Complete outage of 230kV Villianur substation

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Event Details of tripping Remedial actions taken by Puducherry

Points for discussion

Complete outage of 230KV Villianur Sub-Stationat 08:40hrs on 30.05.2018

Failure of R-phase 230KV CT of 230/110KV 100MVA ICT-2 at 230KV Villianur Station.

230KV Neyveli-Villianur and 230KV Pondy-Villianur lines tripped from Neyveli end and Pondicherry end respectively. This led to loss of supply to 230KV Villianur Station.

Fault clearing time – 360ms

Failed CT replaced with R-phase CT from 230KV Pondy-VillianurLine. Auto Transformer-II brought back into service on 31.05.2018.

One set of new CT’s (CT ratio 400-800-1000-1200-1600/1A) were erected in Pondycherryline bay on 31.06.2018.

Bus bar protection taken out of service

Actions initiated to replace the in service aged 230KV HV-I & HV-II CTs with the newly supplied CTs. (Six numbers of new 230KV CTs with CT ratio 300-600-1000-1200-1600/1A)

Non-operation of protection at Villianur

Action plan for replacement plan of CT’s for 230KV HV-I & HV-II CT’s

Bus bar protection out of service

Complete outage on 30.05.2018

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Event Details of tripping Remedial actions atkenby Puducherry


Complete outage of 230KV Villianur Sub-Station at11:23hrs on 05.06.2018

Failure of B-phase pole of breaker of 110KV Villianur – Kalapet line at Villianur end

HV & LV back up over Current relaysof both Auto Transformer-I & IIacted for R, Y & B-phase. ProtectionDC failed as the terminal fuse of110 Volt Station Battery bank.

230KV Neyveli-Villianur and 230KV Pondy-Villianur lines tripped from Neyveli end and Pondicherry (zone-3) end respectively.


1. Failed Kalapet feeder CB wasreplaced with spare new CB. CT’sof Kalapet feeder replaced withnew CT’s as a precautionarymeasure.

2. Provision of 4sets of pipe inpipe chemical earthing at theback yard of control room

3. Switch yard earthingmeasurement (30.06.2018). Individual and combined earthpit value of Kalapet feeder bay –3 ohm.

Other earth pit values observedon higher sides, actions initiatedto strengthen earthing of switchyard.

Healthiness status of remaining equipments in 132kV switchyard

Switchyard earth resistance higher than permissible limits.


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Event Details of tripping Remedial actions atkenby Puducherry


Complete outage of 230KV Villianur Sub-Station at07:29 Hrson 15-06-2018

failure of B-phase 230KV CurrentTransformer (Make: TELK) of HV-IBreaker of 230/110KV 100MVAAuto Transformer-I at Villianursubstation

230KV Neyveli-Villianur and 230KVPondy-Villianur lines tripped fromNeyveli end and Pondicherry (zone-2) end respectively.


Failed CT replaced with Y-phase CT from 230KV Pondy-VillianurLine. Auto Transformer-I brought back into service on 15.06.2018.

One set of new CT’s (CT ratio 400-800-1000-1200-1600/1A) were erected in Pondycherryline bay on 31.06.2018.

Bus bar protection taken out of service

Actions initiated to replace the in service aged 230KV HV-I & HV-II CTs with the newly supplied CTs. (Six numbers of new 230KV CTs with CT ratio 300-600-1000-1200-1600/1A)

Reason for non-operation of protection at Villianur.

Action plan for replacement plan of CT’s for 230KV HV-I & HV-II CT’s

Bus bar protection out of service


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1. Complete Outage of 230kV Villianur station at 08:42 Hrs on 30-05-2018

• Triggering Incident: Failure of R-ph CT of HV side 100MVA 230/110kV transformer 2.

• Transformer protection did not operate.• Following feeders tripped:

• 230kV NLC st-2 - Villianur tripped at NLC end on over current protection.• 230kV Pondy - Villianur line tripped at Pondy end on zone 2 distance operation.

• Load loss: 130 MW

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DR/30_05_2018_220kV Villianur/Neyvelli end_NEYVELI TS2_VILLIANUR_LINE_DR.pdf

DR/30_05_2018_220kV Villianur/Neyvelli end_NEYVELI TS2_VILLIANUR_LINE_DR.pdf

DR/30_05_2018_220kV Villianur/Neyvelli end_NEYVELI TS2_VILLIANUR_LINE_EL.pdf

DR/30_05_2018_220kV Villianur/Neyvelli end_NEYVELI TS2_VILLIANUR_LINE_EL.pdf

DR/30_05_2018_220kV Villianur/Pondy end_PONDY_VILL_DR.pdf

DR/30_05_2018_220kV Villianur/Pondy end_PONDY_VILL_DR.pdf

DR/30_05_2018_220kV Villianur/Pondy end_PONDY_VILL_EL.pdf

DR/30_05_2018_220kV Villianur/Pondy end_PONDY_VILL_EL.pdf

PMU Plots:

Dip in B-phase voltage indicate fault in B-phase.

Fault Clearance time: 360 msecs

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SLD of 230kV Villianur station Annexure-V

Page 8 of 13

2. Complete Outage of 230kV Villianur station at 11:23 Hrs on 05-06-2018

• Triggering Incident: Failure of R-ph breaker of 110kV Kalappet - Villianur line at Villianur

end.• Fault was cleared by tripping of the upstream feeders.• Following feeders tripped:

• 230kV NLC st-2 - Villianur tripped at NLC end on Z3, distance protection.• 230kV Pondy - Villianur line tripped at Pondy end on Z3 distance protection.


Villianurend

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DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_NLC end DR.pdf

DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_NLC end DR.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Pondy end DR.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Pondy end DR.pdf

DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_NLC end EL.pdf

DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_NLC end EL.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Pondy end EL.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Pondy end EL.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Villianur end EL.pdf

DR/05_06_2018_230kV Villianur/PONDY_VILL_Villianur end EL.pdf

DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_Villianur end EL.pdf

DR/05_06_2018_230kV Villianur/NEYVELI TS2_VILLIANUR_Villianur end EL.pdf

PMU Data Plots

Dip in B voltage was observed in all the

phases of 400kV Sriperumpudur bus

during the event for 720ms.

Remedial measures taken:

Terminal fuse of 110V battery bank replaced.

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SLD of 230kV Villianur station Annexure-V

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3. Complete Outage of 230kV Villianur station at 07:29 Hrson 15-06-2018

• Triggering Incident: B-phase CT (Make: TELK) of HV-I Breaker of 230/110KV 100MVA Auto

Transformer-I got failed • Fault was cleared by tripping of the upstream feeders.• Following feeders tripped:

• 230kV NLC st-2 - Villianur tripped at NLC end on operation of 86T.• 230kV Pondy - Villianur line tripped at Pondy end on distance protection zone 2.


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DR/15_06_2018_VILLIANUR/16070_SENDEL-NEYVELI TS2_VILLIANUR_LINE_EL.pdf

DR/15_06_2018_VILLIANUR/16070_SENDEL-NEYVELI TS2_VILLIANUR_LINE_EL.pdf

DR/15_06_2018_VILLIANUR/16073_SENDEL-PONDY_VILL_EL.pdf

DR/15_06_2018_VILLIANUR/16073_SENDEL-PONDY_VILL_EL.pdf

DR/15_06_2018_VILLIANUR/16070_SENDDR-NEYVELI TS2_VILLIANUR_LINE_DR.pdf

DR/15_06_2018_VILLIANUR/16070_SENDDR-NEYVELI TS2_VILLIANUR_LINE_DR.pdf

DR/15_06_2018_VILLIANUR/16073_SENDDR-PONDY_VILL_DR.pdf

DR/15_06_2018_VILLIANUR/16073_SENDDR-PONDY_VILL_DR.pdf

PMU Plots:

Dip in B voltage was observed in

400kV Sriperumpudur bus

during the event for 350ms.

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SOUTHERN REGIONAL POWER COMMITTEE - SRPC

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