ABB RELION REX640 Technical Manual page 675

1MRS759142 C
REX640
Technical Manual
I
zs1
A
I
zs1
B
I
zs1
C
Uzs
Operate for
internal fault
GUID-D735D14D-0AC9-4F9E-BB74-2E072FD8CE51 V1 EN
Figure 370: Current flow in all the CTs for an external fault
s
A
o
u
B
r
c
C
e
Ifault
Io
For internal fault
GUID-E40187C9-75F4-472B-8CE3-B76A5685DE23 V1 EN
Figure 371: Current flow in all the CTs for an internal fault
zone of
protection
Io
For external fault
Restrain for
external fault
zone of
protection
Uzs
Io
Operate for
internal fault
Section 4
Protection functions
I
a = 0
I I
b = 0 b = 0
I I
c = 0
I
N
Io
I
N Reference is Neutral
Current
I
N
I
N
Reference is Neutral
Current
Restrain for
external fault
a
b
c
I I
a = 0
a
I I
b = 0
b
I
c = 0
c
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