ABB RELION 620 Series Technical Manual page 469

1MAC504801-IB E
620 series ANSI
Technical Manual
I
zs1
A
I
zs1
B
I
zs1
C
Uzs
Io
Operate for
internal fault
GUID-FAC5E4AD-A4A7-4D39-9EAC-C380EA33CB78 V2 EN
Figure 214: Current flow in all the CTs for an external fault
Protection functions
zone of
protection
I
N
For external fault
Io
I
N Reference is Neutral
Current
Restrain for
external fault
Section 4
I
a = 0
a
I I
b = 0 b = 0
b
I I
c = 0
c
463