Evaluating Protective Relay Performance Through Relay Testing

I ntroduction: Feeder Protective Relaying  Feeder Protection Relays are act as a Primary & Backup Protection  Primary Protection act with in 50-100ms  Backup Protection act when

PRESENTED BY

JAY B THAKAR SAGAR J KOTHARI

E valuating P rotective R elay P erformance

T hrough R elay T esting

I ntroduction: What is Protective

Relaying???

“ Voltage & Current Amplitude, Phase Angle, Frequency

continuously in electrical

networks to detect Faults in

networks & isolate faulty

section ” before any serious

Damage.

2

 Transmission Line Protection

 Electrical Machine Protection

Relays

 Generator Unit Protection

 Transformer Unit Protection

 Motor Unit Protection

3

I ntroduction: Feeder Protective

Relaying

 Feeder Protection Relays are act

as a Primary & Backup Protection

 Primary Protection act

with in 50-100ms

 Backup Protection act when

Primary protection fails Operation

of Backup Protection is Time

4

I ntroduction: Electrical Machine

Protection Relay

 Electrical Machine Protection

Relays: Unit Protection

 Unit Protection relays are Act for

time of unit Protection relays are

30 to 80ms

5

R

I ntroduction: Dynamic Power

 What are the harmonic content & Relay operating

time during an internal fault followed by CT

saturation?????????

 How I can see the performance of Distance

Protection relays on CCVT transient????

7

O utline

 W hat is the existing relay test practice?

 W hat is the advance relay test practice?

 S ummary

W hat is the Existing Relay Test Practice?

10

 Constant Current Method:

phase angle and Ramps Voltage from normal voltage to

threshold value until the relay operates

is varying at time

P hasor Testing: S teady State Testing

Voltage Ramp starts to decrease from Normal Voltage to until relay Trips

11

 Dynamic State Testing means

true fault simulated Power

12

D ynamic State Testing: T est P rocedure

Power System Model

13

P hasor Testing: D ynamic State Testing

Pole Slipping Detected &

Issued Trip command

 Transformer Inrush current, Over

Excitation phenomenon & It’s Effect

on relay operation

T ransient Testing:

W hat is the Advance Relay Test Practice?

Product Design Application Test

Simultaneously Apply Fundamental Freq & Harmonic Freq components (Including DC OFFSET) of Voltages and Currents Phasor

16

Simulation Programs like

Test Software (TransWin) Testing Kit (F6150)

Relay

TRIP

V & I Sources

18

T ransient Testing: P reventive Study

Dynamic State Testing

R esults: S ensitivity

Test Cases Description Results

Test Case-1 Initial CT

Operating Time

86.5ms

Test Case-3 CT Saturation for

4-5 Cycles after one cycle

Operating Time

150ms

Test Case-4 Dynamic State

Testing Fault, Fault, Post-Fault)

(Pre-Operating Time

33.4ms

S ummary

 Existing Test Practices serves a limited purpose

to check setting calibration but Not to Evaluate

t h e r e l a y a p p l i c a t i o n p e r f o r m a n c e

 Dynamic State Testing is easy to conduct & more meaningful testing than steady state testing but, still it is on fundamental frequency so it is difficult to known the transient behavior of relays

 Relay performance on transient behavior needs to

be evaluated to assure the best decision

regarding;

 Investment

 Application Practice

 Relay Performance under critical conditions

 Resolve problem for relay design issues

T hank Y ou