GE D90 Plus Instruction Manual page 654

PHASE DISTANCE APPLIED TO POWER TRANSFORMERS
644
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
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
PLUS
D90 LINE DISTANCE PROTECTION SYSTEM – INSTRUCTION MANUAL
CHAPTER 15: THEORY OF OPERATION
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