10
L1
L2
L3
0
I
0
I
-
-
+
+
BS
5A 1A
SPAJ 111 C
U2
U3
1
1
1
1
D
C
B
A
+
Uaux
25
SGR/1
U3
+ -
E
+
-
(~)
(~)
≅
_
10 11
61 62
71 72
70
78
77
81
80
69
68
66
65
SGR
7
5
6
8
3
2
4
START1 SIGNAL1 TRIP2
TRIP1
SPA-ZC_
Rx
Tx
26 27
IRF
IRF
74 75
73
F
START2
TS2
TS1
SGB
SS1
SS2
U1
5
4
I/O
t >>
t >
Io>
Io>>
SERIAL
PORT
1)
Examples of
application
Example 1.
Feeder earth-fault
protection
Fig. 4. Earth-fault relay SPAJ 111 C used for the protection of an outgoing feeder. The earth-fault
current is measured with a core-balance current transformer. The selector switch positions are
shown in the table on the following page.
1) Blocking signal to be routed to the earth-fault relay of the incoming feeder