GE D90 Plus Instruction Manual page 563

CHAPTER 15: THEORY OF OPERATION
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
Transformer Loop
connection
Dy5 AB
BC
CA
Dy7 AB
BC
CA
Dy9 AB
BC
CA
Dy11 AB
BC
CA
Table 25: Phase distance input signals for wye-delta transformers
Transformer Loop
connection
Yd1 AB
BC
CA
Yd3 AB
BC
CA
PHASE DISTANCE APPLIED TO POWER TRANSFORMERS
Current transformation
I _21P - = I
3
AB B
I _21P - = I
3
BC C
I _21P - = I
3
CA A
I _21P - = I
3
AB A
I _21P - = I
3
BC B
I _21P - = I
3
CA
C
I _21P - = I
3
AB C
I _21P - = I
3
BC A
I _21P - = I
3
CA B
I _21P - = I
3
AB B
I _21P - = I
3
BC C
I _21P - = I
3
CA A
Current transformation
1
I = ( I - I - I )
_21P 2
AB A B C
3
1
( )
I = I - I - I
_21P 2
BC B A C
3
1
( )
I = I - I - I
_21P 2
CA C A B
3
1
I = ( I + I - I )
_21P 2
AB A B C
3
1
( )
I = I + I - I
_21P 2
BC B C A
3
1
( )
I = I + I - I
_21P 2
CA A C B
3
Voltage transformation
1
( )
V = V - V
_21P
AB BC AB
3
1
( )
V = V - V
_21P
BC CA BC
3
1
V = ( V - V )
_21P
CA AB CA
3
1
( )
V = V - V
_21P
AB CA AB
3
1
( )
V = V - V
_21P
BC AB BC
3
1
V = ( V - V )
_21P
CA BC CA
3
1
( )
V = V - V
_21P
AB CA BC
3
1
( )
V = V - V
_21P
CA
BC AB
3
1
V = ( V - V )
_21P
CA BC AB
3
1
( )
V = V - V
_21P
AB AB BC
3
1
( )
V = V - V
_21P
BC BC CA
3
1
( )
V = V - V
_21P
CA CA AB
3
Voltage transformation
V _21P = V
3
AB A
V _21P = V
3
BC B
V _21P = V
3
CA C
V _21P - = V
3
AB C
V _21P - = V
3
BC
A
V _21P - = V
3
CA
B
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