Transformer Differential ProtectionCommissioning Tools
TransformerDifferential Protection System
Commissioning Tools
TransformerDifferential Protection System
Commissioning Tools
Transformer Differential ProtectionCommissioning 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
Transformer Differential ProtectionCommissioning 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
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
Y:Y:Y, yyy1:1 Transformer Ratio
1:1 CTs, Normal
Y:Y:Y, yyy1:1 Transformer Ratio
1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
Three Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
Very high restraintcurrent
Very low differential current
Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
W1, Phase A at 0 degreesW2, Phase A at 180 degreesW3, Phase A at 180 degrees
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
Transformer Differential ProtectionCommissioning Tools
W1, Phase A
W2, Phase AW3, Phase A
Analog Traces
Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
W1, Phase A
W2, Phase AW3, Phase A
3 = (-1.5) + (-1.5)
RMS
Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
Y:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs
Roll ØA, W2
Y:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs
Roll ØA, W2
Transformer Differential ProtectionCommissioning Tools
Three Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2
Transformer Differential ProtectionCommissioning Tools
0.0
0.0
High level of positivesequence current
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
Transformer Differential ProtectionCommissioning Tools
Restraint current lessthan through current
High differential current
Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
W1, Phase AW2, Phase A
W2, Phase AW3, Phase A
Differential Trip
Analog Traces
Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2
Transformer Differential ProtectionCommissioning Tools
W1, Phase AW2, Phase A
W2, Phase AW3, Phase A
3 = (-1.5) + (-1.5)
Differential Trip
RMS
Digital Oscillography:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Roll ØA, W2
Transformer Differential ProtectionCommissioning Tools
∆:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs, Normal
∆:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
Three-Line:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
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
Transformer Differential ProtectionCommissioning Tools
Very high restraintcurrent
Very low differential current
Advanced Metering:Y:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
W1, Phase A at 0 degreesW2, Phase A at 30 degreesW3, Phase A at 30 degrees
W1, Phase A at 0 degreesW2, Phase A at 180 degreesW3, Phase A at 180 degrees
Phaser Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
W1, Phase A
W2, Phase AW3, Phase A
Analog Traces
Digital Oscillography:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Normal
Transformer Differential ProtectionCommissioning Tools
∆:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs
Roll A-∆
∆:Y:Y, yyy
1:1 Transformer Ratio
1:1 CTs
Roll A-∆
Transformer Differential ProtectionCommissioning Tools
Three Line:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆
Transformer Differential ProtectionCommissioning Tools
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-∆
Transformer Differential ProtectionCommissioning Tools
Restraint current lessthan through current
High differential current
Advanced Metering:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆
Transformer Differential ProtectionCommissioning Tools
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-∆
Transformer Differential ProtectionCommissioning Tools
W1, Phase A
W2, Phase AW3, Phase A
Differential Trip
Analog Traces
Digital Oscillography:∆:Y:Y, 1:1 Ratio, 1:1 CTs, Roll A-∆
©2008 Beckwith Electric Co., Inc.