ABB 615 Series - Page 568

Differential protection
(87A, 87B, 87C) for
Zone A
Differential protection
(87A, 87B, 87C) for
Zone B
Bus coupler
Stabilizing
resistor R
s
Stabilizing
resistor R
s
2…....7
Feeder
1
Feeder
8
2000/1A
2000/1A
2000/1A
2000/1A
Y
2000/1A
Y
GUID-97462931-644F-4EFD-8C9A-AF61A3C870B8 V1 EN
Figure 286: Example for busbar differential protection
Bus data:
V
n
20 kV
I
n
2000 A
I
kmax
25 kA
10 feeders per protected zone including bus coupler and incomer.
CT data is assumed to be:
CT
2000/1 A
R
in
15.75 Ω
V
kn
436 V
I
e
<7 mA (at U
kn
)
R
m
1Ω
Section 4 1MAC059074-MB A
Protection functions
562 615 series ANSI
Technical Manual