Modeling and simulation of the industrial numerical distance ...

Simulation

Simulation: Transactions of the Society for

Modeling and Simulation International

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� 2014 The Society for Modeling and

Simulation International

DOI: 10.1177/0037549714532961

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Modeling and simulation of theindustrial numerical distance relayaimed at knowledge discoveryin resident event reporting

Mohammad Lutfi Othman, Ishak Aris and Noor Izzri Abdul Wahab

AbstractIn the motivation of tapping the strong potential of computational intelligence in discovering knowledge of protectiverelay operations using data mining, modeling and simulation of an actual industrial numerical distance relay and itsrecording facility are a vital requisite. This is justified by the practicality and necessity of divulging the decision algorithmhidden in the recorded relay event report using computational intelligence-based data mining. Thus, this paper studiesthe detailed modeling and simulation of an industrial AREVA MiCOM P441 distance relay, accommodated together withits own simulated event report recording facility. The idea is to provide the flexibility of allowing the simulated eventreport to have sufficiently significant depth and breadth for data mining purposes. The modeled relay has operated cor-rectly and discriminatively in deciding circuit breaker pole(s) to be tripped in stipulated assertion times as per theMalaysian licensee’s requirements for various faults and protected zones along a transmission line. It has subsequentlybeen validated successfully by the performance of the real field AREVA MiCOM P441 distance relay belonging to theMalaysian licensee. With the successful modeling and simulation of the AREVA MiCOM P441 distance relay and itsrecording facility, such subsequent works as data extraction and preparation, computational intelligence-based data min-ing for relay decision algorithm discovery and finally a relay analysis expert system development can certainly be exe-cuted. These subsequent applications are briefly explored as a demonstration of the benefit offered after the successfulmodeling of the relay.

KeywordsDistance protection, numerical protective relay, data mining, computational intelligence, Knowledge Discovery inDatabases, association rule, Rough Set Theory, relay modeling

1. Introduction

Using a suitable data mining strategy, the decision algo-

rithm of a numerical protective relay (such as a distance

relay) in the form of rules of operation logic underpinning

its event report can be intelligently discovered. An intelli-

gent data analysis process called Knowledge Discovery in

Databases (KDD) has been successfully employed to intel-

ligently discover, from the distance relay resident event

report, the hidden relay decision algorithm. This algorithm

is made up of a collection of prediction rules (C)pred

D) and

the subsequently filtered relay association rules (C)assoc

D)

related to the faults the relay has operated on. The single

relay association rule that has been successfully discov-

ered is the ultimate knowledge domain of distance protec-

tive relay behavior to be divulged from each fault. It being

a single rule is in essence the much desired

hypothesization of the relay operation characteristic. This

rule and others can then be collated to form a rule base in

the distance protective relay performance analysis expert

system.1,2

Getting to know the predetermined operation character-

istics is the first step in any analysis of relay performance

of a distance protective relay. These can be identified by a

Center for Advanced Power and Energy Research, Department of

Electrical and Electronic Engineering, Faculty of Engineering, Universiti

Putra Malaysia, Malaysia

Corresponding author:

Mohammad Lutfi Othman, Center for Advanced Power and Energy

Research, Department of Electrical and Electronic Engineering, Faculty of

Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor,

Malaysia.

Email: [email protected]

at PENNSYLVANIA STATE UNIV on September 18, 2016sim.sagepub.comDownloaded from

http://sim.sagepub.com/

process known as hypothesization of expected relay beha-

vior.1–4 Hypothesization of relay behavior can be imple-

mented in a number of ways:

i. soliciting expert knowledge from protection

engineers;

ii. extracting information from manufacturer’s relay

operation manuals and technical specifications;

iii. divulging information hidden in the recorded

relay event report.

The first two strategies are hard to carry out. Engineers’

expertise differs from person to person while operation

manuals usually present information that is too much to

churn out. The third strategy offers a rather challenging

approach. However, with intelligent data mining under the

framework of KDD, hypothesization can be invoked to

discover the expected relay behavior.1,2 This last approach

is more preferable since the hidden knowledge to be dis-

covered is a sure portrayal of exactly how the relay should

or has operated as designed. Othman et al.1,2 laid out a

novel data mining technique employing the integrated

computational intelligence of Rough Set Theory, the

Genetic Algorithm and Rule Quality Measure in deducing

the operation behavior of a distance relay in the form of

association rules (symbolized as C)assoc

D). C denotes the

attribute set of various multifunctional protection elements

that correlate partially or wholly to the decision class D,

that is, attribute for trip assertion status. The KDD process

involves the selection, preprocessing and transformation

of relay data resident in the event report, data mining and

interpretation of discovered knowledge.1,2,5

Data mining is particularly crucial in the overall process

of KDD. It functions as a pattern (model, or decision algo-

rithm) extractor by applying some specific computational

intelligence on data.6 In power system faults and protec-

tion analysis, data mining has gained considerable atten-

tion among protection engineers and researchers.7–9 The

growing volume of data available in digital form has accel-

erated this interest.

In the motivation of tapping the strong potential of the

integrated computational intelligence of Rough Set

Theory, the Genetic Algorithm and Rule Quality Measure

demonstrated by Othman et al.,1,2 modeling and simula-

tion of the industrial numerical distance relay and its

recording facility are necessary. Looking at the actual pro-

prietary event report retrieved from an SEL-321 digital

distance protective relay device shown in Figure 1,10 for

example, the relay decision system where the relay opera-

tion is recorded is rather concise for data mining manipu-

lation. (The relay decision system is also called relay DT,

essentially taken from ‘decision table’, an alternative term

for event report.) Thus, it is necessary that the relay

recording facility be modeled so that flexibility is gained

in allowing the modeled distance relay to be able to

‘record’ the event report with depth and breadth.

Over the years, many modeling practices have focused

on the functional aspects of relay operations and their

dynamic simulations in power system contingencies.11–13

None has emphasized the modeling of its internal relay

recording facility in order to record every possible multi-

functional protective element and show how its behavior

is dictated by its functional design and protection para-

meter settings.

The strength of data mining strategy in relay knowledge

discovery is tested based on the complexity of the relay

event report.1,2 Thus, the modeling approaches of the relay

and its recording facility must be able to make available

substantial amounts of detail in terms of:

i. number of attributes representing multifunctional

protective elements’ measured/calculated data

and logical operands (i.e. breadth in columns);

and

ii. time-tagged events (i.e. depth in rows).

It is necessary that modeling of the relay and its record-

ing facility be made based on an actual industrial numeri-

cal relay that allows a sufficiently large event report to be

simulated. This is due to the numerously available multi-

functional protective elements in a single device. In this

regard a numerical distance relay is suitable considering its

built-in multiple protection-specific and protection-support

functions.

2. Modeling and simulation of actualindustrial distance relay and itsrecording facility

In order to emulate a real numerical relay, a distance relay

is modeled and simulated using PSCAD/EMTDC to pro-

vide the simulated relay event report and the parameter

recording in a universal IEEE COMTRADE format. This

‘recorded’ relay event report in a raw form can then be

extracted and converted into a pre-data-mining decision

system DT during the KDD process.1,2 The following tasks

shall be carried out.

i. Modeling and simulation of a numerical distance

protective relay and its data recording system

based mainly on the commercial AREVA

MiCOM P441 relay that is used by TNB (Tenaga

Nasional Berhad; the Malaysian power licensee)

in their transmission line protection.14 Where

design details are not explicitly divulged, some

related features from the Schweitzer Engineering

Laboratories Inc.’s SEL321 relay are refered to.15

This cross-referencing approach is merely for

2 Simulation: Transactions of the Society for Modeling and Simulation International



academic purposes so that any desired multifunc-

tional elements of the distance relay can be rea-

sonably modeled, parameters tuned and simulated

results studied. The intended records shall con-

sists of time signals of oscillographic measure-

ments (filtered and secondary), binary signals of

internal protective element states, external input

of various devices and relay trip output, and set-

ting parameters.

ii. Modeling and simulation of a transmission net-

work based on a 500 kV double-sourced parallel

circuit as practiced by TNB and recommended

by Conseil International des Grands Reseaux

Electriques (CIGRE).16,17 The primary instanta-

neous currents and voltages under fault condi-

tions are then applied on the modeled distance

relay (for functional and dynamic tests), and

played back on a real TNB’s AREVA MiCOM

Figure 1. SEL-321 proprietary event report depicting the relay decision system (relay DT).

Othman et al. 3



P441 distance relay (for the purpose of validating

the relay model).

iii. Validation of the functional and dynamic perfor-

mance of the modeled distance relay using

OMICRON’s PC-controlled test set (comprising

TEST UNIVERSE software and CMC 256 test

equipment set18) to playback captured simulated

currents and voltages into TNB’s real AREVA

MiCOM P441 distance relay. If the performance of

the modeled relay is validated, the ‘recording’ of

the simulated IEEE COMTRADE relay event

report and setting files will be used in KDD for dis-

covering the knowledge of distance relay

operations.

2.1. Development of the distance relay model

AREVA’s MiCOM P441 is a modern numerical distance

relay that operates using its phase and ground distance

quadrilateral protective elements. The exact emulation of

the AREVA relay and its application in line with TNB’s

practice imply that the modeled relay and its COMTRADE

event recording facility comply with the Institute of

Electrical and Electronics Engineers (IEEE), International

Electrotechnical Commission (IEC), CIGRE, and TNB

guidelines and standards stipulated in Monseu,17

IEEE,19,20 IEC21 and TNB.22

The quadrilateral type of distance relay as opposed to

the mho distance relay is preferably used by TNB in high-

voltage (HV) and extra high-voltage (EHV) transmission

line protection particularly because of the following:

i. the quadrilateral type is more flexible in provid-

ing sufficient resistive coverage to faults with

high resistance, particularly in ground faults;

ii. the mho type must be provided with a blinder for

load restriction on impedance, whereas the resis-

tive reach settings in the quadrilateral type can

act as a blinder at the same time;23

iii. the quadrilateral type provides high-speed tripping

of resistive faults when a pilot channel is not

present.

iv. the quadrilateral type is fairly immune to in-line

load switching.24

The disadvantages of using the quadrilateral type as

compared to the mho distance relay are as follows:

i. the quadrilateral type is affected by errors in the

current and voltage measurements when the resis-

tive reach is much greater than the reactive reach;

ii. the quadrilateral type is affected by system non-

homogeneity (i.e. unequal source and line impe-

dance angles);

iii. the quadrilateral type is affected by zero-

sequence mutual coupling in parallel lines.24

From the survey, no detailed modeling of modern

AREVA MiCOM P441 distance relay has ever been made.

Modeling this protective relay using PSCAD/EMTDC

involves creating numerous modules/submodules, each of

which is designated for either protection-specific or

protection-support function. The features imbedded in the

modeled distance relay are summarized in Table 1 and

shown in Figure 2.

The Basic Distance Protection comprises the following:

i. Quadrilateral Phase–Phase Distance Elements

(21P, i.e. 21AB, 21BC and 21CA) that measure

the positive sequence impedance of the faulted

line for phase–phase faults (AB, BC, and CA),

phase–phase–ground faults (ABG, BCG and

CAG) and three-phase faults (ABC);

ii. Quadrilateral Phase–Ground Distance Elements

(21G, i.e. 21AG, 21BG and 21CG) that measure

the positive sequence impedance of the faulted

line for phase–ground faults (AG, BG, and CG)

and three-phase faults (ABC).

Since both types of distance elements have four-zone

directional quadrilateral operation characteristics, there are

a total of:

i. twelve measuring elements in 21P; and

ii. twelve measuring elements in 21G.

The aforementioned Basic Distance Protection schemes

are suitable for standalone applications where no signaling

channels are available. As illustrated in Figure 3, the Basic

Distance scheme is suitable for single or double circuit

lines fed from one or both ends. In general, zones 1 and 2

provide main protection for the line in times Z1onT and

Z2onT, respectively, with zone 3 reaching further to pro-

vide backup protection in time Z3onT for faults on adja-

cent circuits and zone 4 in providing the reverse protection

in time Z4onT for faults behind the relay.

The phase–phase fault quadrilateral characteristics illu-

strated in Figure 4 are used in conjunction with the phase-

to-phase impedance loop measurement, the model of

which is represented in the equations shown in Table 2

that are derived according to Figure 5.

The phase–ground fault quadrilateral characteristics

illustrated in Figure 4 are used in conjunction with the

phase-to-ground impedance loop measurement, the model

of which is represented in the equations shown in Table 3

that are derived according to Figure 5.

The coordination between zones is determined to satisfy

the following conditions:




i. zone reaches: ImpedanceZone1-fwd \ImpedanceZone2-fwd \ ImpedanceZone3-fwd (each

zone operation can be manually enabled or dis-

abled as desired);

ii. time coordination: TimeZone1-fwd \ TimeZone2-fwd\ TimeZone3-fwd (each of these zone operation

times is initiated as soon as the relay picks up

when the impedance measurement enters the

above corresponding zone operation characteristic);

iii. ImpedanceZone4-rev is independent;

iv. TimeZone4-rev = TimeZone3-fwd;

v. resistive reaches of 21P elements: R1g(Zone1)

\ R2g(Zone2) \ R34g(Zone3/4) \ minimum

load impedance of the heaviest load;

vi. resistive reaches of 21G elements: R1ph(Zone1)

\ R2ph(Zone2) \ R34ph(Zone3/4) \ mini-

mum load impedance of heaviest load (i.e.

(Vnom. ph-ph(min) / O3) / (1.2 3 Inom. load(max)),

where 1.2 factor is to approximate the heaviest

load);

Table 1. Features of the distance relay model for various protection-specific or protection-support functions.

Basic distance • Phase–Phase Quadrilateral Distance Elements (21G): Measure Z1 of faulted line forphase–phase faults (3), phase–phase–ground faults (3) and three-phase fault (1).

• Phase–Ground Quadrilateral Distance Elements (21P): Measure Z1 of faulted line forphase–ground faults (3) and three-phase fault (1)

• The two types of impedance measurement element consist of:- Zone 1 forward directional instantaneous- Zone 2 forward directional time-delayed zone- Zone 3 forward directional time-delayed zone- Zone 4 reverse directional time-delayed zone

Schemes • Basic Distance schemes (21P/21G)• Channel-aided Distance schemes:

- Permissive Underreach Transfer Trip Protection accelerating Z2 (PUP Z2)- Permissive Underreach Transfer Trip Protection via forward start (PUP Fwd)- Permissive Overreach Transfer Trip Protection with overreaching Z2 (POP Z2)- Permissive Overreach Transfer Trip Protection with overreaching Z1 (POP Z1)- Blocking Overreach Transfer Trip Protection with overreaching Z2 (BOP Z2)- Blocking Overreach Transfer Trip Protection with overreaching Z1 (BOP Z1)- Current Reversal Guard to prevent maloperation of POP Z1, POP Z2, BOP Z1 and

BOP Z2- Weak Infeed scheme (WI) to supplement permissive overreach:

- Weak Infeed activation- Weak Infeed Echo

Standby (backup) DirectionalEarth Fault (DEF) protection

• Element 1: Definite-Time (DT) or Inverse-Definite-Minimum-Time (IDMT) time delayedDEF scheme

• Element 2: Definite-Time (DT) time delayed DEF scheme• Channel-aided DEF scheme:

- Permissive Overreach Transfer Trip Protection DEF (POP DEF)- Blocking Overreach Transfer Trip Protection DEF (BOP DEF)- Weak Infeed scheme (WI) to supplement permissive overreach DEF:

- Weak Infeed DEF activation- Weak Infeed DEF echo

Features • Pole Dead Supervision (PDS)• Directional Negative Sequence Overcurrent Supervision (NSOC, 67Q)• Negative Sequence Directional Element (NSD, 32Q)• Current Transformer Supervision (CTS)• Voltage Transformer Supervision (VTS)• Load Encroachment Supervision (LES)• Fault Type Identification Scheme (FTIS)• Power Swing Blocking (PSB)• Phase Distance Overcurrent Supervision (PPOC, 50P)• Ground Distance Overcurrent Supervision (PGOC, 50G)• Trip Decision Logic Module• Trip Setting/Resetting Logic Module• Switch Onto Fault Protection (SOTF)• Trip On Reclose (TOR)

Non-protection features • Event reports- Fault records- Oscillography records

• Setting records

Othman et al. 5



Figure 2. Part illustrations of various protection-specific or protection-support functions featured in the distance relay model.




vii. the protection tripping time varies according to

the zone of operation as practiced by TNB.

Determining the four-sided polygon shape of the quad-

rilateral distance elements of both phase and ground units

requires using the zone and resistive reaches. Figure 6

illustrates the PSCAD-derived vertexes of the polygonally

shaped quadrilateral distance elements, the derivations of

which are shown in Figure 7. The calculated polygon ver-

texes can then be used to set the operation characteristics

of the quadrilateral distance elements.

The power system that the modeled distance relay is to

protect is a 500 kV double-sourced transmission system, as

shown in Figure 8. This transmission system layout is used

by TNB in their dynamic performance evaluation of the dis-

tance relay using a real-time digital simulator, RTDS,16 which

is adopting from CIGRE’s guidelines.17 The pertinent trans-

mission system parameters, models for current transformers

(CTs) (2000A/1A), capacitor coupled voltage transformers

(CCVTs) (500 kV/110 V), and the circuit breaker auxiliary

contacts are as shown. With these parameters, the zone

reaches used in Figure 7 are derived as shown in Figure 9.

The resistive reaches are set independently of the impe-

dance reach along the protected line. Rph defines the maxi-

mum amount of fault resistance additional to the line

impedance for which a phase-distance zone will trip,

regardless of the location of the fault within the zone. The

resistive reach setting of the ground distance elements, Rg,

is set to cover the desired level of earth fault resistance,

but to avoid operation with minimum load impedance.

Fault resistance would comprise arc-resistance and tower

footing resistance.

(a)

(b)

Z1onT

Relay1 Relay2

R1-Z1

R1-Z2

R2-Z1R2-Z2

Total line impedance

R1-Z3

R2-Z3

R1-Z4

R2-Z4

time

time

Z2onT

Z3onTZ4onT

Z1onT

Z2onT

Z3onTZ4onT

R1-Z1

Z1onT

R1-Z2

Z2onT

R1-Z3

Z3onT

R1-Z4

Z4onT

Trip CB1

Relay 1

R2-Z1

Z1onT

R2-Z2

Z2onT

R2-Z3

Z3onT

R2-Z4

Z4onT

Trip CB2

Relay 2

CB1

Bus1

CB2

Bus2

Relay 1 Relay 2

Figure 3. (a) Main and backup protections in the basic distance scheme where no signaling channels are needed. (b) Trip logic.

Othman et al. 7



No distance elements may operate in situations where

faults occur with high fault resistance. In this case, such

backup protections as channel-aided Directional Earth

Fault (DEF) protection and Negative Sequence

Overcurrent (NSOC) protection are modeled as submo-

dules that provide greater sensitivity to high resistivity, as

identified in Table 1.

In the case of power swing (oscillation in power flow)

following a power system disturbance, the impedance pre-

sented to a distance relay may move away from the normal

load area and into one or more of its tripping (start-up)

characteristics. The Power Swing Blocking (PSB) element

is thus modeled as a protection-support feature, as stated

in Table 1 that indentifies power swings following a power

system disturbance. There are basically trip-blocking and

trip-unblocking modes that are implemented with respect

to the different nature of the power swing, that is:

i. the relay should be blocked from tripping in the

event of a stable power swing;

ii. the relay should also be blocked from tripping

during loss of stability (loss of synchronism/out

of step condition) since there may be a utility

strategy for a controlled system break up during

such an event;

iii. the relay should be unblocked for tripping

(allowed to trip) in the case of faults evolving

during the occurrence of a power swing.

The PSB element detects a stable power swing or loss

of synchronism condition when all three phase–phase

measured impedances (Zab, Zbc and Zca) take longer than

at least 5 milliseconds to pass through the DR (resistive)

and DX (reactive) impedance band that surrounds the

entire phase-distance fault trip characteristic defined by

zones 3 and 4, as shown in Figure 10. In this case the dis-

tance relay should be blocked from tripping provided that

the thresholds of Ir, I2 and Iph are not exceeded, which are

indications of imminent faults. In the modeling, the inner

boundary of the DR-DX band that is made up of zones 3

and 4 is renamed zone 5 while the outer boundary is

named zone 6.

When high-speed fault clearance of all transient or per-

manent faults is required over the entire length of a pro-

tected line, a Channel-aided Distance Protection scheme

can be employed if selected in the simulation run.

Fault type identification is particularly important in

single-pole tripping schemes. Pole tripping involving

either one or all of the three phases requires that proper

phase selection is made so as to select the correct phase

and ground distance elements.25 Thus, the Fault Type

Identification Scheme (FTIS) element is modeled to deter-

mine the types of fault involved (phase–ground, phase–

phase–ground, phase–phase or three-phase) and to assist

Figure 4. Operation characteristics and resistive reaches ofphase–phase and phase–ground quadrilateral distance elements.

Table 2. Models used for the phase-to-phase impedance loopmeasurements.

Description Formula usedin the modeling

Fault impedance seen by distance relay Vαβ / (Iα– Iβ)Measured phase–phase faultimpedance loop

ZF = Z1+ (RFph / 2)

Fault resistance reach RFph / 2Quadrilateral start element angle θSE = :Z1

Vαβ : voltage of phases A-to-B, B-to-C or C-to-A; Iα or Iβ : current of

phase A, B or C; Z1: positive sequence impedance of line; RFph: fault arc

(flashover) resistance.




the Trip_Decision_Module (trip decision logic) in decid-

ing the faulted phase and setting the correct single-pole or

three-pole tripping according to TNB’s requirements,22

shown in Table 4.

In some power system configurations, an earth fault

relay may not be able to detect residual current, and phase

overcurrent elements may not operate because they have

been set higher than the maximum load current, thereby

Figure 5. Phase-to-phase and phase-to-ground impedance loops.

Othman et al. 9



limiting the relay’s sensitivity. Therefore, a NSOC element

is modeled to provide time-delayed backup protection for

any uncleared asymmetrical (phase–phase, phase–ground

and phase–phase–ground) faults downstream where nega-

tive sequence currents are always present. The NSOC ele-

ment gives greater sensitivity to resistive phase–phase

faults, where phase overcurrent elements may not operate.

In order to emulate a real numerical relay event record-

ing, the modeled distance relay is provided with a relay

event report and parameter recording in a universal IEEE

COMTRADE format, as shown in Figure 11. The record-

ing time step is based on the common 16 samples-per-

cycle, which is settable in the AREVA MiCOM P441 relay

and the SEL321 relay. This ‘recorded’ relay event report

in a raw form is then extracted and converted into a pre-

data-mining decision system DT by a data management

software, DIAdem, from National Instruments.26 In the

DIAdem environment, Visual Basics scripts are coded to

run the whole process of importing, selecting, preproces-

sing, transforming and finally converting and saving the

relay data, as shown in Figure 12.

2.2. Validation of the distance relay model

The modeled distance relay’s operations are validated by

comparing them with results found in the real AREVA

MiCOM P441 distance relay. The COMTRADE transient

records of the transmission system model that have been

applied to the modeled relay are played back in the actual

AREVA relay using OMICRON’s PC-controlled test set

comprising TEST UNIVERSE software and the CMC 256

test equipment set, as shown in Figure 13.

Table 5 shows that the actual relay has to be set appro-

priately to operate in the expected transmission system

similar to the settings made on the modeled relay. The

AREVA MiCOM P441 relay accepts phase-to-neutral sec-

ondary voltage injections and not those of phase-to-phase

voltages. It is important to note that during the recordings

for the playback procedure, the modeled relay is disabled

Table 3. Comparison of models used in the modeling and in the AREVA relay for the phase-to-ground impedance loopmeasurements.

Description Formula used in the modeling Formula used in AREVA relay

Fault impedance seen by distance relay VαG / (Iα+ I0k0), I0 iszero-sequence current

VαG / (Iα+ IResk0), IRes isresidual current (= 3I0)

Measured phase–ground fault impedance loop ZF = Z1+ RFg / (1 + (k0/3)) ZF = Z1+ RFg / (1 + k0)Fault resistance reach RFg / (1 + (k0/3)) RFg / (1 + k0)Residual compensation factor k0 = (Z0–Z1) / Z1 k0 = (Z0–Z1) / 3Z1Quadrilateral start element anglea θSE = : ((2Z1+Z0) / 3) θSE = : (2Z1+Z0)

aBoth equations are essentially equal; VαG: voltage of phase A-to-ground, B-to-ground or C-to-ground; Iα: current of phase A, B or C; Z1: positive

sequence impedance of line; Z0: zero-sequence impedance of line; RFg: ground fault resistance.

Figure 6. Vertexes of phase and ground quadrilateral distanceelements.




so that any measurements are without signal changes in

response to modeled relay operations. The reaction of the

AREVA MiCOM P441 distance protective relay tested

with such signals should generate the following relay resi-

dent COMTRADE records logged in its own internal non-

volatile RAM or EEPROM, ready for retrieval:

i. event records;

ii. fault (type and location) records;

iii. disturbance (oscillographic analog/digital wave-

form) records, compressed or uncompressed; and

iv. setting (configuration data) files.

3. Results and discussion

In order to understand the novel supervised learning tech-

nique of hypothesizing expected relay behavior within the

purview of integrated computational intelligence of Rough

Set Theory, the Genetic Algorithm and Rule Quality

Measure as desired by Othman et al.,1,2 the modeled dis-

tance protective relay has been subjected to the following

fault characteristics. In these cases, communication-aided

protection of the remote relay (Relay 2) is not simulated.

i. AG fault: 40 km forward (20% B2-B3, zone 1),

simulation time 1 s, fault inception at 0.5 s, fault

duration 0.1 s. For other faults such as the follow-

ing, different recording duration settings are used

to correspond to various fault durations and fault

clearance times.

ii. AB fault: 40 km forward (20% B2-B3, zone 1),


duration 0.1 s.

iii. ABG fault: 40 km forward (20% B2-B3, zone 1),


duration 0.1 s.

iv. ABC fault: 40 km forward (20% B2-B3, zone 1),


duration 0.1 s.

Figure 7. Calculations for determining vertexes of quadrilateral distance elements (only those for ground distance elements areshown).

Othman et al. 11



v. AG fault: 205 km forward (103% B2-B3, zone

2), simulation time 2 s, fault inception at 0.5 s,

fault duration 0.7 s (0.5 s also ok).

vi. AG fault: 250 km forward (125% B2-B3, zone

3), simulation time 5 s, fault inception at 0.5 s,

fault duration 3.5 s.

vii. AG fault: 32 km reverse (40% B2-B1, zone 4),


duration 3.5 s.

Table 6 summarizes the results of the modeled relay’s

(i.e. Relay 1) behavior in response to various fault condi-

tions. Figures 14–16 illustrate some sample plots in

response to AG, ABG and ABC faults in 40 km forward

(20% B2-B3, zone 1).

It is obvious that the corresponding Phase–Phase

Quadrilateral Distance Elements (21AB, 21BC or 21CA)

have correctly picked up a phase–phase fault in the faulted

zone of the B2-B3 section of the transmission system:

i. AB phase–phase fault by I_Z1PhDist_TripLogic

module as demonstrated by the attribute

Dist_pp_Z1 (i.e. specifically Dist_ab_Z1);

ii. ABG phase–phase–ground fault by

I_Z1PhDist_TripLogic module as demonstrated

by the attribute Dist_pp_Z1 (i.e. specifically

Dist_ab_Z1); and

iii. ABC three-phase fault by I_Z1PhDist_TripLogic

module as demonstrated by the attribute

Dist_pp_Z1 (i.e. specifically Dist_ab_Z1,

Dist_bc_Z1, and Dist_ca_Z1 together).

The corresponding Phase–Ground Quadrilateral

Distance Elements (in this case only 21AG) have also cor-

rectly picked up phase–ground faults in various faulted

zones of the transmission system:

i. AG phase–ground fault by

I_Z1GndDist_TripLogic module as demonstrated

by the corresponding attributes Dist_pg_Z1 (i.e.

specifically Dist_ag_Z1), Dist_pg_Z2 (i.e.

Dist_ag_Z2), Dist_pg_Z3 (i.e. Dist_ag_Z3) and

Dist_pg_Z4 (i.e. Dist_ag_Z4).

In the case of the ABG phase–phase–ground fault and

ABC three-phase fault, from the plots of ground impe-

dance versus ground distance characteristics in Figures 15

and 16, the Phase–Ground Quadrilateral Distance

Elements seem to have wrongfully picked up the faults

as shown by the measured trajectory locus of the

Auxillary contacts of Breaker CB1

CRZ1CRZ2CRZ4

CB52a

VI

CSZ1

CSZ2CSZ4

Distance Relay R1

WI_CS

WI_CR

VTmcb_aux

DEF_CR

DEF_CS

CB52b

DEF_WI_CR

DEF_WI_CS

Trip_PhATrip_PhBTrip_PhC

I_Relay_R1

CB1A_CB1B_CB1C_

V_CB1secI_CB1sec

VTmcb1

CB52a_1CB52b_1

CSZ1_CB1CSZ2_CB1CSZ4_CB1

WI_CS_CB1DEF_CB1

DEF_WI_CS_CB1


WI_CS_CB2DEF_CB2

DEF_WI_CS_CB2

CRZ1CRZ2CRZ4

CB52a

VI

CSZ1

CSZ2CSZ4

Distance Relay R2

WI_CS

WI_CR

VTmcb_aux

DEF_CR

DEF_CS

CB52b

DEF_WI_CR

DEF_WI_CS


II_Relay_R2

CB2A_CB2B_CB2C_

V_CB2secI_CB2sec

VTmcb2

CB52a_2CB52b_2


WI_CS_CB1DEF_CB1

DEF_WI_CS_CB1


WI_CS_CB2DEF_CB2

DEF_WI_CS_CB2

VB_CB1

CB52a_1A

CB52a_1BCB52b_1A

CB52b_1B

123

IC_CB1IB_CB1

IA_CB1

VC_CB1

1

V_CB1

3

2

VA_CB1

Auxillary contacts of Breaker CB2CB52a_2A

CB52a_2B

CB52a_2C

CB52b_2A

CB52b_2B

CB52b_2C

1 2 3

VA_CB1(sec)VB_CB1(sec)VC_CB1(sec)

IA_CB1(sec)IB_CB1(sec)IC_CB1(sec)

V_CB1sec

I_CB1sec

IC_CB2IB_CB2

IA_CB2

VC_CB2

VB_CB2

1

V_CB2

3

2

VA_CB2

1 2 3

VA_CB2(sec)VB_CB2(sec)VC_CB2(sec)

IA_CB2(sec)IB_CB2(sec)IC_CB2(sec)

I_CB2sec

V_CB2sec

VTmcb1 VTmcb2

123

123

CB52a_1CCB52b_1C

CB52a_1 CB52b_1

123

123

CB52a_2 CB52b_2

CT

VT

2000/1A

500kV/110V

CT

VT

2000/1A

500kV/110VI_CB1 I_CB2

B_CB1

C_CB1

A_CB2

B_CB2

C_CB2

VTmcb2_AVTmcb2_BVTmcb2_C

VTmcb1_AVTmcb1_BVTmcb1_C

0Simulating healthy VT

00

123

0Simulating healthy VT

00

L

L

L

L

L

L

Z1 = 59.63 [ohm] /_ 88.08 [deg]

VPh

500.0 [kV], 50.0 [Hz]100.0 [MVA]

Z1 = 39.92 [ohm] /_ 87.90 [deg]

V Ph

500.0 [kV], 50.0 [Hz]100.0 [MVA]

Ph

Angl

e

Volta

ge

Ph Angle

Voltage

B3B2

VA

CB1 CB2

CB3 CB4

B1

S22T

S12T

B4

S32T

S31T

S21T

Fault Zone 120% B2-B3

LINE 1, 80km

LINE 2, 200km

LINE 3, 60km

LINE 4, 200km

S41T

Fault Zone 2103% B2-B3 (8.3% B3-B4)

S11T

Fault Zone 440% B2-B1

Power Source 1 Power Source 2

VA

VA

VA

CB6

VA

CB5 CB7

VA

CB8

F1tpF2tpF1tmF2tm

F5tpF5tm

32km48km

200km

160km40km

VA

VA

Relay 1 Relay 2

5km 45km

A_CB1

S33T

Fault Zone 496%(B2-B3 + B3-B4) or (83% B3-B4)

F7tmF7tp

10km

V Ph

Bx

CBx

VA

SxyT- Three-phase power

source model

- Variable input slider

- Bus (substation)

- Three-phase circuit breaker

- Transmission line (e.g from bus x to bus y)

- Multimeter

- fault

LEGEND:

L- CCVT (Capacitor coupled voltage transformer)

- CT (Current transformer)

Source positive sequence impedance:Z1GA = 39.92/_87.90deg ohmZ1GB = 59.63/_88.08deg ohmSource negative sequence impedance:Z2GA = Z1GASource zero sequence impedance:Z0GA = 31.92/_88.03deg ohmZ0GB = 71.54/_87.99deg ohmLine positive sequence impedance:Z1L = 7.9982e-5 + j 2.7299e-4 ohm/mLine positive charging susceptance:B1L = 4.1692e-9 S/m, orX1L = 239.854e6 ohm.mLine zero sequence impedance:Z0L = 3.0917e-4 + j 9.2995e-4 ohm/mLine zero charging susceptance:B0L = 2.3231e-9 S/m, orX0L = 430.459e6 ohm.mZero sequence mutual impedance:Z0mL = 2.3005e-4 + j 6.2796e-4 ohm/m

Figure 8. Double-sourced transmission system single line and distance relay models (500 kV).




Zone 1 (forward) = 0.8 x Z1sec = 0.8 x [7.0384 + j24.0231 Ω (or 25.0329∡73.67º Ω)] = 5.6307 +j19.2185 (or 20.0263∡73.67 º Ω)

Zone 2 (forward) = 100% (B2-B3 line 2) + 50 %( B3-B4 line 3) = (200km + 50%.60km) x Z1sec Ω/m = (200km + 30km) x (Z1prim Ω/m x CT/VT) = 230km x (Z1prim Ω/m x CT/VT) = 230km x (7.9982e-5 + j 2.7299e-4 Ω/m) x 0.44 = 8.0942 +j27.6266 Ω (or 28.7879∡73.67º Ω)

Zone 3 (forward) = 100% of the protected line + 120% of the longest adjacent line = 100 %( B2-B3 line 2) + 120 %( B3-B4 line 4) = (100%200km + 120%200km) x Z1sec Ω/m = 440km x (Z1prim Ω/m x CT/VT) = 440km x (7.9982e-5 + j 2.7299e-4 Ω/m) x 0.44 = 15.4845 + j52.8509 Ω (or 55.0726∡73.67º Ω)

Zone 4 (reverse) ≥ ((Remote zone 2 reach (i.e. relay 2 at CB2)) x 120%) minus the protected line impedance. ≥ [(100% (B3-B2 line 2) + 50 %( B2-B1 line 1)) x 120%] - 100%(B3-B2 line 2) ≥ [(100%200km + 50%80km) x 1.2) - 100%200km] x Z1sec Ω/m ≥ 88km x (Z1prim Ω/m x CT/VT) ≥ 88km x (7.9982e-5 + j 2.7299e-4 Ω/m) x 0.44 ≥ 3.0970 + j 10.5702 Ω (or 11.0145∡73.67º Ω) i.e. ≤ -3.0970 - j 10.5702 Ω (reverse)

Z1 = R1 + jX1 (secondary +ve seqimpedance, ohm)

Z1 = Z1m(/_Z1p) (secondary +veseq impedance, ohm)

X1secperm

R1secperm*

N

D

N/D

*

R1prim/m

X1prim/m

R1sec_ProtL

CT/VT

*

*

R1prim/m x CT/VT= R1sec/m

X1prim/m x CT/VT= X1sec/m

R1sec_ProtL

X1sec_ProtL

ZONE 1 PHASE REACH SETTINGS

Zone1 % of TL_ProtL (eg, 80%)

*

*

R1_Zone1

X1_Zone1

TL_ProtL

X1sec_ProtL

R1sec_ProtL

X1sec_ProtLR1_Zone1

X1_Zone1

I_DistProt_Settings_...R1_Zone1

5.63073

X1_Zone1

19.2185

CT

VT

R1primperm

X1primperm

I_DistProt_Settings_Module ...

54321

Zone1 % of TL_ProtL (eg, 80%)

0.8

Y

X

MP

M

PY

X Z1m

Z1p

I_DistProt_Settings_Module : Contr...R1sec_ProtL

7.03842

X1sec_ProtL

24.0231

Z1p

73.6702

Characteristic angle of transmission line(Same angle repeated for all zones)

Z1p

X1sec_ProtLR1sec_ProtL

CHARACTERISTIC IMPEDANCEOF TRANSMISSION LINE


D +

F

+

Length of shortest adjacent line (eg. 60km)

TL_ShrtAdjL

% of TL_ShrtAdjL, (eg, 50%)

*% TL_ShrtAdjL

*

*

R1sec_ProtLX1sec_ProtL

D +

F

+

R1_Zone2

X1_Zone2

R1secperm

X1secperm

R1_Zone2

X1_Zone2

I DistProt Settings ...R1_Zone2

8.09418

X1_Zone2

27.6266

I DistProt Settings Module ...

500000

0

Length of short...

60000

m

4

3

2

1

% of TL_ShrtA...

0.5

ProtL +LongAdjL

*

If AREVA is adopted

ProtL + 1.2 x LongAdjL

*


D +

F+

Length of longest adjacent line (eg. 200km)

TL_LongAdjL

*

*


D +

F

+

R1_Zone3

X1_Zone3

R1secperm

X1secperm

*

% of (ProtL + LongAdjL), (eg. 120%)

R1_Zone3

X1_Zone3


500000

0

Length of longe...

200000

m

3

2

1

% of (ProtL + L...

1.2

% of TL_LongAdjL, (eg. 120%)

TL_LongAdjL

If AREVA is adopted

ProtL +LongAdjL

ProtL + 1.2 x LongAdjL

TNB approach

SignalName

SignalName I_DistProt_Settings_...R1_Zone3

15.4845

X1_Zone3

52.8509

ZONE 4 PHASE REACH SETTINGS D +

F

+

Length of shortest line behind relay (eg. 80km)

TL_ShrtBhndL

% of TL_ShrtBhndL, (eg, 50%)

*% TL_ShrtBhndL

*

*


D +

F

+

R1secperm

X1secperm*

R1_Zone4

X1_Zone4

*ProtL +

ShrtBhndL

ProtL +ShrtBhndL

D +

F

-

D +

F

-

(ProtL +ShrtBhndL) x 120%

[(ProtL + ShrtBhndL) x120%] - ProtL

(ProtL +ShrtBhndL) x 120%

X1_Zone4

R1_Zone4

1.2120%

*-1

*-1

I_DistProt_Settings_...R1_Zone4

-3.0969

X1_Zone4

-10.5702

R1_Zone4 & X1_Zone4 haveto ve numbers


500000

0

Length of short...

80000

m

4

3

2

1

% of TL_ShrtB...

0.5

Figure 9. Setting calculations of zone reaches for zone 1, 2, 3 and 4.

Othman et al. 13



phase–ground impedance loops of ground distance units

that traverse within the characteristics. This, however,

would not cause misoperations unexpectedly of the

I_Z1GndDist_TripLogic module, because its invocation is

blocked by the supposedly unasserted AGflt signal input

from the FTIS element (see Figure 2). Figure 15(b) illus-

trates the output signals of the FTIS module where in the

case of the ABG fault, ABGflt is asserted while the AGflt

signal is not in order to enable the pick-up signal produced

in the Dist_ab_Z1 attribute.

The modeled Relay 1 has also operated correctly in

sending signals to the circuit breaker and deciding which

pole(s) of the circuit breaker CB1 is (are) to be tripped.

The operations are agreeable to what have been stipulated

by TNB, as shown in Table 4.22

In terms of relay tripping time, the simulation results

have also demonstrated the correctness of the modeled

Relay 1’s time taken in asserting the trip signals upon

detection of the simulated faults. All the read relay trip-

ping times are in accordance to what have been set in theFigure 10. Power swing detection characteristics.

Table 4. Pole tripping schemes.

Fault types Number of pole to be opened according to TNB guidelines

≥ 275 kV 132 kV

Z1F Z1BkUp Z2F Z3F Z4R POP PUP Z1F Z1BkUp Z2F Z3F Z4R POP PUP

Ph-G (3) 1 3 3 3 3 1 1 3 3 3 3 3 3 3Ph-Ph-G (3) 3 3 3 3 3 3 3 3 3 3 3 3 3 33Ph-G (1) 3 3 3 3 3 3 3 3 3 3 3 3 3 3Ph-Ph (3) 3 3 3 3 3 3 3 3 3 3 3 3 3 33Ph (1) 3 3 3 3 3 3 3 3 3 3 3 3 3 3

TNB: Tenaga Nasional Berhad.

Table 5. Important parameters set in both the relay model and the actual AREVA MiCOM P441 relay.

Parameter Value

• Line positive sequence secondary impedance, Z1 25.033;73.67��• Line length 200 km• CT 2 kA:1 A• VT 500 kV:110 V• Zone 1 secondary impedance reach 20.026;73.67��• Zone 2 secondary impedance reach 28.788;73.67��• Zone 3 secondary impedance reach 55.073;73.67��• Zone 4 secondary impedance reach 11.015;-106.33��• Phase-distance secondary resistive reach, Rph/2 Zone 1: 4 �, Zone 2: 12.5 �, Zone 3/4: 19 �• Ground distance secondary resistive reach, R1g / (1 + k1 / 3) Zone 1: 5.2 �, Zone 2: 10 �, Zone 3/4: 14.32 �• Residual compensation factor, k0 (= k1 = k2 = k34) 2.4459;–2.9021�• Tripping time delay Zone 1: instantaneous, Zone 2: 450 ms, Zone 3/4: 3000 ms• Power swing impedance band DR (resistive): 2 �, DX (reactive): 2 �• Power swing block time delay 5 ms




Figure 11. Recording of time signals of oscillographic measurements (filtered and secondary), binary signals of internal protectiveelement states, external input of various devices and relay trip output. Recording for setting parameters is not shown.

Othman et al. 15



relay and in fact in accordance to TNB’s requirements for

different zones of faults.

The average duration of circuit breaker operation time

of 44.2 ms is close to the set time delay in the circuit

breaker simulation of 40 ms.

In the validation of the modeled distance protective

relay operations, Figure 14(b) shows the logical plot of the

zone 1 trip signal of the actual AREVA P441 relay against

the played back secondary voltages and currents for A-G

zone 1 fault. DistGenTrp is named by TNB for any general

trip, which for this fault condition represents the zone 1

trip. It is discovered that the tripping time of the AREVA

relay is 46.47 ms, which is slower than 0.3 and 25 ms of

the relay model and TNB requirement, respectively. This

proves that the relay model has operated desirably accord-

ing to the TNB requirements but the actual AREVA relay

PSCAD ‘relay-generated’ COMTRADE files fromthe 12-channel recorder components

(analog and digital signals or setting parameters)

Select from PSCAD‘.emt’ folder directory

Import intoDIAdem

Concatenate filesinto single files

Segregation to form relaydecision system, DT, of:i. condition attributes (C)ii. decision attributes (D)

Data stability analysis toform a single- instanced

table of parametersettings

Data cleaning againstnoise and missing

values.(Differentiation betweenreal, absolute interger/zero,and binary values)

Data cleaning againstnoise and missing

values(Differentiation betweenreal, absolute interger/zero,and binary values)

Create attribute ‘time’for relay DT

Construct newcontinuous-valued

attibutes (e.g. ph-ph andph-gnd impedances from

voltages and currents

Construct newbinary-valued

attibutes

Novel discretization ofph-ph and ph-gnd

impedancesPhase comparatorof zone quadrilateral

characteristics

Syntesization byAND-compoundingimpedance pick-up

Data valueconditioning

Simplificationaccording to

zonal representation

Prepared relay DTsaved in ‘.xls’ and ‘.tdm’

(e.g. R1.xls, R1.tdm)

Relay parameters settingssaved in ‘.xls’(e.g. R1set.xls)

(Categorical data)

(Continuous data)

(Categoricaldata)

(Rough-Set-Theorybased data mining )

Raw relay datasaved in ‘.tdm’

(e.g. R1raw.tdm)

(PRAY Expert System)

Figure 12. Flowchart of data preparation strategy of relaydecision system DT.

Table

6.Resultsoftherelay’sbehaviorinrespondingto

variousfaultconditions.

Fault

type

Location

offault

Distance

unit

pickupa

Timeof

distance

unitpick

up(s)

Timeof

tripping

signalassertion

(s)

Pole(s)to

betripped

Durationof

relay

tripping

time

(ms)

Timeof

circuit

breaker

operation(s)

Durationof

circuitbreaker

operationtime

(ms)

Duration

offault

clearance

time(m

s)

Compliance

withTNB’s

required

tripped

pole?

Compliance

withTNB’srequired

relaytripping

time

accordingto

zone?

AB

CD

EF

G=(E

–D)

HI=(H

–E)

J=(H

-D)

AG

Zone1

Dist_pg_Z1

0.5149

0.5154

A0.5

0.5614

46

46.5

Yes

Yes(25ms)

AB

Zone1

Dist_pp_Z1

0.5136

0.5139

ABC

0.3

0.5607

47.1

47.1

Yes

Yes(25ms)

ABG

Zone1

Dist_pp_Z1

0.5136

0.5139

ABC

0.3

0.5609

47

47.3

Yes

Yes(25ms)

ABC

Zone1

Dist_pp_Z1

0.5136

0.5139

ABC

0.3

0.5551

41.2

41.4

Yes

Yes(25ms)

AG

Zone2

Dist_pg_Z2

0.5186

0.9689

ABC

450

1.0101

41.2

491.5

Yes

Yes(450ms)

AG

Zone3

Dist_pg_Z3

0.5186

3.5194

ABC

3000

3.5636

44.2

3045

Yes

Yes(3000ms)

AG

Zone4

Dist_pg_Z4

0.5199

3.5204

ABC

3000

3.5631

42.7

3043

Yes

Yes(3000ms)

Ave.=

44.2

a ‘Dist_pp’meansphase–phaseand‘Dist_pg’means

phase–ground

typeofthedistance

elem

ents.

TNB:TenagaNasionalBerhad.




has not been able to do so. The significant difference

between the tripping time of the AREVA relay and that of

the relay model is attributed to the fact that the tripping

time of the former takes into account delays due to its algo-

rithm execution processes and hardware operations, such

as microprocessor and trip contact motions. There is hardly

any delay in the relay model tripping time, which is mainly

due to the FORTRAN program execution in the PSCAD/

EMTDC tool that might take at least a time step, thus

instantaneous tripping is impossible for zone 1. Table 7

compares different relay tripping times between TNB

requirements, the actual AREVA MiCOM P441 distance

relay and its PSCAD/EMTDC model. It is apparent that

the tripping times of the relay model comply satisfactorily

with the TNB requirements and are faster than those of the

actual AREVA relay device. It can be seen that the actual

AREVA relay device operates in an average of approxi-

mately 40 ms from the preset time of instantaneous, 450

and 3000 ms for zone 1, zone 2 and zone 3=4, respectively.This is, as mentioned, due to the inherent hardware and

program execution delays.

The modeled relay event report and parameter record-

ings in universal IEEE COMTRADE format have also

been successfully implemented. Table 8 shows how the

Visual Basics scripts coded in DIAdem for data prepara-

tion are able to:

i. extract data from the modeled relay;

ii. select the recorded vast COMTRADE files;

iii. preprocess to form attributes as shown in the left-

hand column of Table 8; and

iv. transform, convert and save the extracted data

into the attributes shown in the right-hand column

of Table 8 – the required format, ready to be data

mined using the intended techniques employing

integrated computational intelligence of Rough

Set Theory, the Genetic Algorithm and Rule

Quality Measure in deducing the operation beha-

vior of a distance relay in the form of association

rules.

Figure 17 shows how the successful relay and recording

facility models as well as the subsequent data preparation

can then set into motion the strategy of divulging informa-

tion hidden in the recorded relay event report. With the

aforementioned intelligent data mining under the frame-

work of KDD, hypothesization of the decision algorithm

of the modeled AREVA distance relay in the form of

1. PSCAD:Transmissionsystem model& Comtradetransientrecords

2. OMICRON-TEST UNIVERSE:Playback ofComtrade transientrecords

Secondary analogsignals

OMICRON-CMC 256,playback test set& signal amplifier

AREVA MiCOMP 441 distance relay(Comtrade event,fault, disturbance,setting records)

OMICRON

Digital transient record

PSCAD

Figure 13. Preparation and playback of simulated transient fault signals into the AREVA MiCOM P441 distance protective relay.(Inset shows the experimental set up in the Tenaga Nasional Berhad (TNB) laboratory.)

Othman et al. 17



Figure14. (a) Plots in response to the AG fault: 40 km forward (20% B2-B3, zone 1). (b) Plot of zone 1 trip signal of AREVA P441relay under test against played back voltages and currents for the A-G zone 1 fault. The inset depicts the actual light-emitting diodeannunciation and liquid crystal display of the relay after its zone 1 operation.




Figure 15. (a) Plots in response to the ABG fault: 40 km forward (20% B2-B3, zone 1). (b) Output signals of FTIS_Module in thecase of the ABG fault.

Othman et al. 19



association rules can be practically realized as meticu-

lously discussed by the authors in other papers.1,2 The dis-

covered algorithm (for the shown AG fault), symbolized as

C)assoc

D, stipulates exactly what the condition-attribute set

of various multifunctional protection elements is in corre-

lation to the decision class D – that is, the attribute for trip

assertion status.

As discussed by the authors in other papers,1,2 by collat-

ing all the necessary relay association rules discovered

from relevantly possible contingencies trained on the relay,

a maintainable rule base for the inference strategy of a

protective-relay-analysis expert system can be conveni-

ently developed. Figure 18 demonstrates a screen shot of

an expert system called the Protective Relay Analysis

sYstem (PRAY) that is used to analyze the operation of a

protective relay (in this case, distance relay) based on the

decision algorithm discovered from the very same relay

that has been trained earlier under known (and possibly

exhaustive) fault conditions. PRAY is developed using

LabVIEW from National Instruments.27 It runs its relay

Figure 16. Plots in response to the ABC fault: 40 km forward (20% B2-B3, zone 1).




analysis by, firstly, validating whether the protective relay

under test operates correctly as expected by way of com-

parison between hypothesized and actual behavior. Then,

in the case of relay maloperations or misoperations, it diag-

noses the presented symptoms by identifying their causes.

4. Conclusion

This paper discussed the successful modeling and simulation

of an industrial AREVA MiCOM P441 numerical distance

relay, including its recording facility, that was used by the

Malaysian licensee TNB in their transmission line protection.

The protective relay modeling strategy was meticulously

aimed at producing great depth and breadth in the ‘recorded’

event report that is suitable for data mining execution in dis-

covering knowledge of protective relay operations.

The modeled relay had operated correctly and discrimi-

natively in deciding the intended circuit breaker pole(s) to

be tripped in the stipulated assertion times as per TNB’s

requirements for various faults in different zones and,

importantly, emulating the operation of the actual AREVA

MiCOM P441 numerical distance relay. The Phase–Phase

and Phase–Ground Quadrilateral Distance Elements had

correctly picked up respective phase–phase and phase–

ground faults in the faulted zone.

The successful relay and event recording facility mod-

els, as well as the subsequent data preparation, could then

readily facilitate the intelligent data mining strategy under

the KDD framework in order to hypothesize the decision

algorithm of the modeled AREVA distance relay in the

form of association rules.

Finally, an easily maintainable rule base for inference

strategy of a protective-relay-analysis expert system

(PRAY) could be developed using the discovered relay

association rules.

Table 7. Comparison of relay tripping time between Tenaga Nasional Berhad (TNB) requirements, the actual AREVA MiCOM P441distance relay and its PSCAD/EMTDC model.

Fault type Fault location Relay tripping time (ms) % difference(modeled and actual relay)

TNB’srequirement

PSCAD- modeledAREVA relay

Actual AREVAMiCOM P441

AG Zone 1 25a 0.5 46.5 99.9AB Zone 1 25 0.3 64.0 99.5ABG Zone 1 25 0.3 50.2 99.4ABC Zone 1 25 0.3 69.5 99.6AG Zone 2 450 450 494.5 9.0AG Zone 3 3000 3000 3048 1.6AG Zone 4 3000 3000 —b (not available)

aZone 1 is by default set as instantaneous.bThe actual AREVA MiCOM P441 unit has malfunctional zone 4 reverse element. Thus, a test for AG-zone-4 fault has not been carried out.

Figure 17. Integrated execution of Rough Set Theory, GeneticAlgorithm and Rule-Quality Measure-based data mining indeducing the operation behavior of a distance relay in the formof association rule.

Othman et al. 21



Table 8. Construction of new attributes to collectively represent the simplified and discretized version of originally extractedattributes for ease of data mining process.

Attributes prior totransformation,i.e. Q (Attribute name)

Attributes after transformation, i.e. Q’

Attribute name: Attributedescription, Attribute unit

Attribute domain (set of values),i.e. V = Uq∈Q’ Vq

time* (continuous)va_filtvb_filtvc_filtia_filtib_filtic_filt

(These attributes will notinvolve in data mining butare useful for plottingreconstructed waveforms)

irirpVamvbmvcmvapvbpvcpiamibmicmiapibpicp

Zabm: AB_sec_imped, ohm(sec)Zbcm: BC_sec_imped, ohm(sec)Zcam: CA_sec_imped, ohm(sec)Zabp: AB_sec_imped, degZbcp: BC_sec_imped, degZcap: CA_sec_imped, degZagm: AG_sec_imped, ohm(sec)Zbgm: BG_sec_imped, ohm(sec)Zcgm: CG_sec_imped, ohm(sec)Zagp: AG_sec_imped, degZbgp: BG_sec_imped, degZcgp: CG_sec_imped, deg

(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)(continuous)

CB52a_ACB52b_A

CB52_A: Status of Circuit Breaker, status {Unknown, open, closed, failed}

CB52a_BCB52b_B

CB52_B: Status of Circuit Breaker, status {Unknown, open, closed, failed}

CB52a_CCB52b_C

CB52_C: Status of Circuit Breaker, status {Unknown, open, closed, failed}

VTmcb_AVTmcb_BVTmcb_C

VTmcb: Status of VT mcb, phase(open) {0, A, B, C, AB, CA, BC, ABC}

VTSfail_cnfm VTSfail_cnfm: VTSfail_cnfm, logic {0, 1}CRZ1CRZ2CRZ4WI_CRDEF_CRDEF_WI_CR

CR: Carrier received fromremote relay, carrier receive

{0, DEF_WI, DEF, (DEF,DEF_WI), WI,(WI,DEF_WI),(WI,DEF), .........(Z1,Z2,Z4,WI,DEF,DEF_WI)}Note: 26 possible combinations of CRZ1,CRZ2, CRZ4, WI_CR, DEF_CR, andDEF_WI_CR

pg_Z1PkUppg_Z2PkUppg_Z3PkUppg_Z4PkUp

pg_PkUp: Ground DistancePick Up, zone

{0, 3, 4, 23, 123}

pp_Z1PkUppp_Z2PkUppp_Z3PkUppp_Z4PkUp

pp_PkUp: Phase-distancePick Up, zone

{0, 3, 4, 23, 123}

AGfltBGfltCGfltABGfltBCGfltCAGfltABfltBCfltCAfltABC_ABCGflt

FltType: Fault type, phase {no fault, AGflt, BGflt, CGflt, ABGflt, BCGflt,CAGflt, ABflt, BCflt, CAflt, ABC_ABCGflt}

(continued)

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Table 8. (Continued)





ab50_Z1bc50_Z1ca50_Z1

pp50_Z1: Phase Overcurrentsupervision in zone, phase

{0, A, B, C, AB, BC, CA, ABC}










a50_Z1b50_Z1c50_Z1

p50_Z1: Phase Overcurrentsupervision in zone, phase


a50_Z2b50_Z2c50_Z2



a50_Z3b50_Z3c50_Z3



a50_Z4b50_Z4c50_Z4



r50_Z1r50_Z2r50_Z3r50_Z4

r50: Residual Overcurrentsupervision in zone, zone

{0, 1, 2, 3, 4, 12, 13, 14, 23, 24, 34,123, 134, 234, 124, 1234}

PSB_Z1ppPSB_Z2ppPSB_Z3ppPSB_Z4pp

PSB: Zone blocked by PSB, zone {0, 1, 2, 3, 4, 12, 13, 14, 23, 24, 34, 123, 134,234, 124, 1234}

QF32QR32

Q32: Negative sequencedirectionality, direction

{0, Fwd, Rev}

Zload_fwdZload_rev

Zload: Impedance encroachingload characteristic, direction

{0, Fwd, Rev}

Q50_1Q50_2Q50_3Q50_4

Q50: Zone having NonDirNeq Seq OvrCurrt, zone

{0, 1, 2, 3, 4, 12, 13, 14, 23, 24, 34, 123, 134,234, 124, 1234}

Dist_ab_Z1Dist_ab_Z2Dist_ab_Z3Dist_ab_Z4

Dist_ab: Zone of Ph Dist flt, zone {0, 3, 4, 23, 123}

Dist_bc_Z1Dist_bc_Z2Dist_bc_Z3Dist_bc_Z4

Dist_bc: Zone of Ph Dist flt, zone {0, 3, 4, 23, 123}

Dist_ca_Z1Dist_ca_Z2Dist_ca_Z3Dist_ca_Z4

Dist_ca: Zone of Ph Dist flt, zone {0, 3, 4, 23, 123}

(continued)

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Table 8. (Continued)





Dist_ag_Z1Dist_ag_Z2Dist_ag_Z3Dist_ag_Z4

Dist_ag: Zone of Gnd Dist flt, zone {0, 3, 4, 23, 123}

Dist_bg_Z1Dist_bg_Z2Dist_bg_Z3Dist_bg_Z4

Dist_bg: Zone of Gnd Dist flt, zone {0, 3, 4, 23, 123}

Dist_cg_Z1Dist_cg_Z2Dist_cg_Z3Dist_cg_Z4

Dist_cg: Zone of Gnd Dist flt, zone {0, 3, 4, 23, 123}

pg_TrpZ1fpg_TrpZ2fpg_TrpZ3fpg_TrpZ4r

pg_Trp: Ground Distance Trip, zone {0, 3, 4, 23, 123}

pp_TrpZ1fpp_TrpZ2fpp_TrpZ3fpp_TrpZ4r

pp_Trp: Phase-distance Trip, zone {0, 3, 4, 23, 123}

TrpPUPZ2TrpPUPFwdTrpPOPZ2POPZ2TrpPOPZ1

Trip_CAPerm: Channel-aidedpermissive trip signals, PUP_POP

{0, POPZ1, POPZ2, (POPZ2,POPZ1), PUPFwd,(PUPFwd,POPZ1), ..............PUPZ2,PUPFwd,POPZ2,POPZ1}Note: 24 possible combinations of TrpPUPZ2,TrpPUPFwd, TrpPOPZ2, TrpPOPZ1

TrpBOPZ2TrpBOPZ1

Trip_CABlck: Channel-aidedtrip-blocking signals, BOP

{0, BOPZ1, BOPZ2, (BOPZ2,BOPZ1)}

WI_TrpAWI_TrpBWI_TrpC

WI_Trp: Weak Infeed trip pole, phase {0, A, B, C, AB, BC, CA, ABC}

WI_CRTrp WI_CRTrp : WI_CRTrp, logic {0, 1}DEFelem1_trpDEFelem2_trp

DEFelem_Trp: DEF element trip signals, element {0, 1, 2, 12}

DEF_WI_CRTrp DEF_WI_CRTrp: DEF_WI_CRTrp, logic {0, 1}TrpPOP_DEFTrpBOP_DEF

Trip_DEF_CA: DEF Channel-aided permissive/blocking signals, POP/BOP

{0, BOP, POP}

DEF_WI_TrpADEF_WI_TrpBDEF_WI_TrpC

DEF_WI_Trp: Directional Earth FaultWeak Infeed trip pole, phase



Trip: Relay pole trip signals, phase {0, A, B, C, ABC}

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Acknowledgement

The authors thank TNB, the main Malaysian power licensee, for

assistance rendered in providing invaluable information regarding

the technical requirements in modeling the distance protective

relay based on AREVA and SEL and in modeling a transmission

line based on the practice by CIGRE as adopted by TNB.

Funding

The authors gratefully acknowledge the Universiti Putra

Malaysia for the Research University Grant Scheme (RUGS 2-

2012) [project no. 05-02-12-2204RU and vote no. 9377400].

References

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ery in distance relay event report: a comparative data-mining

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genetic-algorithm based data mining and rule quality measure

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tics from relay event report. Int J Electr Power Energy Syst

2011; 33:1437–1456.

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work: a survey. IEEE Trans Neural Networks 2002; 13:

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mation. Technical paper, Schweitzer Engineering

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contingencies. Int J Electr Power Energy Syst 2010; 32:

345–350.

Figure 18. Association rules discovered from Knowledge Discovery in Databases involving hybrid Rough Set Theory, GeneticAlgorithm and Rule Quality Measure-based data mining can be employed as a rule base for the inference strategy of the ProtectiveRelay Analysis sYstem (PRAY).

Othman et al. 25



12. McLaren PG, Mustaphi K, Benmouyal G, et al. Software

models for Relays. IEEE Trans Power Delivery 2001; 16:

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tection technical manual, version B1.2. Publication: P44x/

EN T/E33. AREVA T & D Worldwide Contact Center,

http://dc434.4shared.com/doc/nPROOdqs/preview.html (2006).

Accessed July 3, 2009.

15. SEL. SEL-321/SEL-321-1 phase and ground distance relay

directional overcurrent relay and fault locator: Instruction

manual, Date Code: 20070122, Schweitzer Engineering Lab.

Inc., Pullman, Washington, https://customer.selinc.com/

metadot/index.pl?iid=2533 (2007). Accessed July 3, 2009.

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Author biographies

Mohammad Lutfi Othman received his BSc degree

with honor distinction (Magna Cum Laude) in electrical

engineering from the University of Arizona (UofA),

Tucson, Arizona, USA, in 1990, his MSc and PhD degrees

in electrical power engineering from the Universiti Putra

Malaysia (UPM), Serdang, Malaysia, in 2004 and 2011,

respectively. Currently, he is a Senior Lecturer at the

Department of Electrical and Electronics Engineering,

Faculty of Engineering, Universiti Putra Malaysia. He is a

Researcher and the founding member of the Centre for

Advanced Power and Energy Research (CAPER), UPM.

His areas of research interest include, among others, mod-

eling, simulation and operation analysis of power system

protection and numerical protective relays using computa-

tional intelligent-based data mining and expert system

approaches. He is an advocator of Rough Set Theory

applications in electrical power system researches. Due to

his rich involvement in building services installation

works, his researches also involve building energy man-

agement studies. He has developed protection related soft-

ware such as Power System Protection (PSP, a power

system protection interactive multimedia simulator and

expert system software) and Protective Relay Analysis

sYstem (PRAY, a distance protective relay performance

analysis expert system). He is a principal author of numer-

ous manuscripts of high impact factor journals such as

Simulation: Transactions of the Society for Modeling and

Simulation International, IEEE Transaction on Power

Delivery, International Journals of Electrical Power and

Energy Systems (Elsevier), Applied Soft Computing

(Elsevier) and other SCOPUS indexed journals and con-

ference proceedings. He is a technical editor for journals

of the Asian Network for Scientific Information, a

reviewer of various manuscripts submitted for journal and

conference proceeding publications and a technical eva-

luator of university research grant applications. He has

been a Keynote Speaker and Session Chair of an interna-

tional IEEE conference. He is a Professional Engineer reg-

istered under the Board of Engineers Malaysia (BEM), a

corporate member of the Institution of Engineers Malaysia

(IEM), a member of the IEEE USA, a member of the

IEEE Power and Energy Society (IEEE-PES), a member

of the IEEE Computational Intelligence Society (IEEE-

CIS), a member of the Institution of Engineering and

Technology (IET) UK, a member of the International

Rough Set Society (IRSS) and a member of Phi Kappa

Phi (FKF) Honor Society, The University of Arizona. As

a Professional Engineer, he is a Mentor and Professional

Interviewer for IEM/BEM Professional Engineer

aspirants.

Ishak Aris received his BSc degree in Electrical

Engineering from the George Washington University in




1988 and MSc and PhD degrees in power-electronics

engineering from the University of Bradford, UK, in 1991

and 1995, respectively. Currently he is a professor at the

Department of Electrical and Electronic Engineering,

Universiti Putra Malaysia. His areas of interest include

power electronics and drive systems, robotics, artificial

intelligence, vision systems, automotive electronics and

avionics.

Noor Izzri Abdul Wahab graduated from the

University of Manchester Institute of Science and

Technology (UMIST), UK, in Electrical and Electronic

Engineering (1998), received his MSc in Electrical Power

Engineering from the Universiti Putra Malaysia (UPM)

(2002) and his PhD (Electrical, Electronic and System

Engineering) from Universiti Kebangsaan Malaysia

(UKM) (2010). He is a Senior Lecturer in the Electrical

and Electronic Engineering Department, UPM. His areas

of interest include power system quality, power system

stability studies and application of artificial intelligence in

power systems.

Othman et al. 27



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