ABB Relion 620 Series - Operating procedures; Monitoring

TC1
TC2
Control +
Control -
-A1
-A1
-TO1
-F1
+J02-F1 control -
+J02-F1 control +
-Q0
-TO2
+J02 -A1
TC1
TC2
Control +
Control -
-A1
-A1
-TO1
-F1
+J01-F1 control -
+J01-F1 control +
-Q0
-TO2
+J01 -A1
AUX. POWER
AUX. POWER
+J01 +J02
Figure 18: Redundant protection fail-safe principle, example 2
J01 Feeder #1 panel
J02 Feeder #2 panel
Q0 Circuit breaker (CB)
TO1 Relay trip output #1
TO2 Relay trip output #2
A1 Protection relay
TC1 CB trip coil 1
TC2 CB trip coil 2
F1 Miniature circuit breaker
In example 2, the fail-safe approach aims at securing circuit breaker tripping even
if a relay fails. A relay in a panel measures also the adjacent panel’s currents (and
voltages) and receives the necessary primary device’s position information. In other
words, the relay in a panel functions as a backup relay for the adjacent panel.
This approach allows service continuation while the failed relay is waiting for spare
parts or a complete replacement. The backup protection features provided by the
adjacent panel’s relay do not necessarily fully match the features available in the
main relay.
TC1
TC2
Control +
Control -
-A2-A1
TO
-F1
-Q0
TO
AUX. POWER
AUX. POWER
Figure 19: Redundant protection fail-safe principle, example 3
1MRS757644 H
Basic functions
620 series
Technical Manual
81