ABB RELION REX640 Technical Manual page 731

1MRS759142 F
W2
Figure 415: Connection of current transformers of Type 1 and example of currents
during an external fault
W2
Figure 416: Connection of current transformers of Type 2 and example of currents
during an external fault
Similar connections are done for a three-winding transformer.
If the rated primary current of the current transformers is not equal to the rated
current of the power transformer on a side of the transformer, setting parameters
CT ratio Cor Wnd 1 , CT ratio Cor Wnd 2 and CT ratio Cor 3 must be used to correct
REX640
Technical Manual
A B C
W1
W3
A B C
W1
W3
A B
1/5A
A1
N
1/5A
B1
N
1/5A
C1
N
W1
W2
1/5A
A2
N
1/5A
B2
N
1/5A
C2
N
A
1/5A
A1
N
1/5A
B1
N
1/5A
C1
N
W1
W2
1/5A
A2
N
1/5A
B2
N
1/5A
C2
N
Protection functions
C
1/5A
N
1/5A
N
1/5A
N
W3
1/5A
N
1/5A
N
1/5A
N
B C
1/5A
N
1/5A
N
1/5A
N
W3
1/5A
N
1/5A
N
1/5A
N
A1
B1
C1
A2
B2
C2
A1
B1
C1
A2
B2
C2
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