Testing the SEL-311L Line Current Differential Relay with ProTesTYAKOV KNOBEL

Sr. APPLICATION ENGINEERDOBLE ENGINEERING COMPANY, USA.

SEL-311L Line Current Differential With Full Distance Backup

87L Restrain

SEL-311L SEL-311L

Zone 1Zone 2Zone 4Zone 3

87L Operate87L Restrain

SEL 311L Line Current Differential Relay

z Line Current Differential for Two or Three Terminal with Tapped Load Overcurrent

z Backup Options from simple Overcurrent to Full 4 Zone Pilot Aided Distance

z Protest Plan concentrates on 87 and Tapped Load O/C

z See SEL 311C test plan for other element tests

z Relays Include Test Aids

SEL 311L with Setting APP=87L

Bus

50 51 67

52

87L

SEL 311L with Setting APP=311L

Bus

50

52

5187L

25/79

21/68

81

67

27/59

Line Current Differential Testing

z Communications Channel is an Integral Component of the Protection

z Testing at Local Terminal May Result in Tripping at Remote Terminal

z Single and Multi- Ended Testing Methods are Available

z Relays Include Test Aids

Single-Ended Testing

z Each SEL-311L May Be Tested Independently

z Remote 87L Must Be Blocked to Prevent Tripping

z Built-in Features Stub Bus Logic Loop Back

Loop Back for Testing with One Relay

z Simulates Internal Faults Only.

z Differential Current Is 2 x Applied Test Current.

z 87L Pickup Is One Half of Setting Value.

z Alpha Plane Will Always Plot at 1 @ 0 Degree.

Channel Loop Back

z If the Channels Are Disconnected, 87L Is Blocked.

z Relay Provides Internal and External Channel Loop Back.

z Local 87L Is Enabled During Loop Back, Remote Is Disabled.

z Hot-Standby Channel Must Be Disabled.

Internal Loop Back

z Differential Current Is 2 x Applied Test Current.

z Available With All Channel Interfaces.

z No External Equipment Is Required.

External Loop Back

z Differential Current Is 2 x Applied Test Current.

z Available With All Channel Interfaces.

z Fiber Channel May Be Jumpered at Rear of Relay, or at Any Patch Panel Between the Relays.

z Multiplexed Channel Loop Back Provided by Equipment Manufacturer.

SEL 311L Differential Element

The SEL-311L restraint characteristic

Surrounds the ideal external fault and load current point

Allows for errors in both magnitude and phase angle caused by CT saturation, channel asymmetry etc.

Is adjustable both in angular extent and radial reach.

SEL 311L Differential Element

OperateRegion

ChannelAsymmetry

Local CTSaturation

Remote CTSaturation

F2

RestraintRegion

Local CTSaturation

Remote CTSaturation

F1

OperateRegion

OperateRegion

OperateRegion

SourceImpedances,Fault Location

SEL-311L Metering

z Local and Remote Currents

z Phase, Zero Sequence, Negative Sequence, and Positive Sequence Currents

z Difference Currents

z Alpha Plane Radius and Angle

z Use as calibration and connection test

Meter Values Proper CT ConnectionsLocal A B C 3I0 3I2 I1

I MAG (A Pri) 587.199 589.804 584.416 6.590 5.432 587.139

I ANG (DEG) -0.20 -120.10 120.10 -101.30 71.30 0.00

Channel X A B C 3I0 3I2 I1

I MAG (A Pri) 592.394 583.617 587.570 7.787 5.726 587.858

I ANG (DEG) 179.50 59.90 -60.20 -175.50 100.70 179.70

Vector Sum A B C 3I0 3I2 I1

I MAG (A Pri) 6.043 6.188 4.400 11.490 10.793 3.160

I ANG (DEG) 148.90 -120.10 -104.20 -142.00 86.30 103.00

Alpha Plane A B C ZERO-SEQ NEG-SEQ POS-SEQ

RADIUS 1.000 0.980 1.000 0.000 0.000 1.000

ANG (DEG) 179.70 179.90 179.60 0.00 0.00 179.70

Inrush Protection

z Increases the minimum trip thresholds and slows the relay operation

z Active when relay it detects that local or remote breaker is open.

z Defeated in test plan by setting the relay 52a logic to assert (52A = 1).

z Otherwise use test set logic sources to simulate 52a

COM Report - Channel Information

=>>COM XSEL-311L 87L Date: 03/14/01 Time: 11:05:44.616EXAMPLE: BUS B, BREAKER 3FID=SEL-311L-X108-V0-Z001001-D20010312 CID=BA2BSummary for 87L Channel XChannel Status Alarms

ROKX = 1 DBADX = 0 RBADX = 0 AVAX = 0For 03/14/01 07:30:52.612 to 0COMM. LOG SUMMARY COMM. STATISTICS# of Error records 33 Last error

Data Error Data Error 17 Longest failure

0.005 sec.Dropout 16 Lost Packets, prev. 24 hours 81Test Mode Entered One Way Delay (Ping-Pong) 0 msec.=>>

Test Connections

SENSE

SENSE

CHX

CHX

OUT104

OUT104

SEL 311L Relay L

IA

IB

IC

IA

IB

IC

IA

IB

IC

N

I1I2

I3

3A /0

3A /-120

3A /-240

N3A /180

3A /+60

3A /-60

OUT104

OUT104

SEL 11L Relay R

IA

IB

IC

IA

IB

IC

ZPLBOI Plot Overlay Shows Alpha Plane Characteristic

PlotII Overlay Shows Characteristic as Traditional Slope Curves

Conclusion

z Protest & F6000 provide resources needed for all tests: single,double and three terminal

z Tests prove unique differential characteristic

z Relay Commissioning Test should be completed as per SEL 311L manual

z Satellite Synchronized tests tests on complete system possible after installation

Relay Operating Time Curves

0.5

1.5

1.0

0.00.0 2 4 6 8 10 12

Multiples of IOP Pickup

O

p

e

r

a

t

e

T

i

m

e

[

c

y

c

]

87L2

87LPH

State Simulation for Go-No-Go/Timing

Go-NoGo tests can be used after installation with Satellite Synch. Test Set

z THANK YOU

SEL-311L Line Current Differential With Full Distance BackupSEL 311L Line Current Differential RelaySEL 311L with Setting APP=87LSEL 311L with Setting APP=311LLine Current Differential TestingSingle-Ended TestingLoop Back for Testing with One RelayChannel Loop BackInternal Loop BackExternal Loop BackSEL 311L Differential ElementSEL 311L Differential ElementSEL-311L MeteringMeter Values Proper CT ConnectionsInrush ProtectionTest ConnectionsZPLBOI Plot Overlay Shows Alpha Plane CharacteristicPlotII Overlay Shows Characteristic as Traditional Slope CurvesConclusionRelay Operating Time CurvesState Simulation for Go-No-Go/Timing