GE G30, Instruction Manual, Page: 253 / 698

GE Multilin G30 Generator Protection System 5-113
5 SETTINGS 5.4 SYSTEM SETUP
5
h) DIFFERENTIAL AND RESTRAINT CURRENT CALCULATIONS
Differential and restraint currents are calculated as follows:
(EQ 5.19)
(EQ 5.20)
(EQ 5.21)
(EQ 5.22)
(EQ 5.23)
(EQ 5.24)
where , , and are the phase differential currents and , , and are the phase restraint currents.
Id
A
I
A
c
1 [ ] I
A
c
2 [ ]
+ =
Id
B
I
B
c
1
[ ]
I
B
c
2
[ ]
+ =
Id
C
I
C
c
1
[ ]
I
C
c
2
[ ]
+ =
Ir
A
max I
A
c
1 [ ] I
A
c
2 [ ] , ( )
=
Ir
B
max I
B
c
1
[ ]
I
B
c
2
[ ] , ( )
=
Ir
C
max I
C
c
1
[ ]
I
C
c
2
[ ] , ( )
=
Id
A
Id
B
Id
C
Ir
A
Ir
B
Ir
C