ABB RELION REX640 Technical Manual page 114

Basic functions
-F1
Figure 35: Redundant protection fail-safe principle, example 1
J01
J0x
Q0
TO
SO
A1
R1
TC
F1
In example 1, the fail-safe approach aims at securing circuit breaker tripping even
if a relay fails. The incomer panel relay indicates the start of selected protection
functions. This start signal is distributed to all load feeder panels. If a relay in the
load feeder panel indicates an IRF status, the start signal of the incomer panel
relay results in circuit breaker tripping. This approach offers basic protection for a
load feeder while the actual protection relay performs a self-supervision controlled
restart sequence.
-F1
Figure 36: Redundant protection fail-safe principle, example 2
114
Control +
+J01
-A1
TO AUX. POWER SO
-Q0
TC
Control -
Incomer feeder panel
Load feeder panels
Circuit breaker (CB)
Relay trip output
Relay start output
Protection relay
Auxiliary relay
CB trip coil
Miniature circuit breaker
Control +
+J01
+J02-F1 control +
+J02 -A1
-A1
-A1
-TO2
-TO1
-Q0
TC1 TC2
+J02-F1 control -
Control -
-F1
Control +
-A1
-TO
Incomer
-Q0
protec on start +
Incomer
protec on start -
Control -
-F1
Control +
-A1
-TO1
AUX. POWER
-Q0
Control -
1MRS759142 F
+J0x
Incomer
protec on start +
-A1
-R1
AUX. POWER
IRF
TC R1
Incomer
protec on start -
+J02
+J01-F1 control +
+J01 -A1
-A1
-TO2
AUX. POWER
TC1 TC2
+J01-F1 control -
Technical Manual
REX640