transformer protection commissioning tools

Transformer Differential ProtectionCommissioning Tools

TransformerDifferential Protection System

Commissioning Tools

TransformerDifferential Protection System

Commissioning Tools


Advanced Metering- Sequence components for all windings

Positive, negative and zeroRestraint and differential currents

Vector Metering- Uncompensated

Raw signal- Compensated

Post vector and ratio corrections

Digital Oscillography- All winding currents

Commissioning Tools


Verifies Relay System Performs as per the Design.

Injection of Current and Voltage to Verify Relay Settings.

Verify proper relay Inputs and Outputs.

Verify Proper Trip Logic.

Verify Tripping and Targets.

Commissioning Testing


Verifies In-Service Relay System is Working Properly.

Done Periodically.

E-M and Static Relays Repeat Commissioning Test.

Digital Relays Require Less Extensive Testing.

Maintenance Testing


Y-Y-Y, yyy, normal load flow

Y-Y-Y, yyy, rolled phase on W2

Δ-Y-Y, yyy, normal load flow

Δ-Y-Y, yyy, rolled phase on W1

Commissioning Examples


Test equipment is used to simulate 3-winding transformers of various winding and CT configurations

Injected 3A into W1, injected 1.5A into W2 and W3 to simulate load flow

Assumed 1:1 transformer and 1:1 CTs for simplicity

Created correct “base case”

Created incorrect case

Used advanced protection system tools to “diagnose” the incorrect connections

Details


Y:Y:Y, yyy1:1 Transformer Ratio

1:1 CTs, Normal

Y:Y:Y, yyy1:1 Transformer Ratio

1:1 CTs, Normal


Three Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


0.0

0.0

High level of positivesequence current

Low levels of negative and zero sequence current

Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


Very high restraintcurrent

Very low differential current



W1, Phase A at 0 degreesW2, Phase A at 180 degreesW3, Phase A at 180 degrees


Vector Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


W1, Phase A

W2, Phase AW3, Phase A

Analog Traces

Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


W1, Phase A


3 = (-1.5) + (-1.5)

RMS

Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


Y:Y:Y, yyy

1:1 Transformer Ratio

1:1 CTs

Roll ØA, W2

Y:Y:Y, yyy


1:1 CTs

Roll ØA, W2


Three Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2


0.0

0.0


Levels of negative and zero sequence current,Positive sequence current not at phase current level

Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2


Restraint current lessthan through current

High differential current

Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2


W1, Phase A at 0 degreesW2, Phase A at 0 degrees (180)

W3, Phase A at 180 degrees

W1, Phase A at 0 degreesW2, Phase A at 0 degrees (180)

W3, Phase A at 180 degrees

Vector Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2




Differential Trip

Analog Traces

Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2




3 = (-1.5) + (-1.5)

Differential Trip

RMS

Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2


∆:Y:Y, yyy


1:1 CTs, Normal

∆:Y:Y, yyy


1:1 CTs, Normal


Three-Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


0.0

0.0


Low levels of negative and zero sequence current



Very high restraintcurrent

Very low differential current





Phaser Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


W1, Phase A


Analog Traces

Digital Oscillography:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Normal


∆:Y:Y, yyy


1:1 CTs

Roll A-∆

∆:Y:Y, yyy


1:1 CTs

Roll A-∆


Three Line:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆


0.0

0.0

Levels of negative and zero sequence current,Positive sequence current not at phase current level

High level of positive sequence current

Advanced Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆


Restraint current lessthan through current

High differential current

Advanced Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆


W1, Phase A at 0 degrees (180)W2, Phase A at 210 degreesW3, Phase A at 210 degrees

W1, Phase A at 0 degrees (180)W2, Phase A at 0 degreesW3, Phase A at 0 degrees

Vector Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆


W1, Phase A


Differential Trip

Analog Traces

Digital Oscillography:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆

©2008 Beckwith Electric Co., Inc.

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