ABB REX 521 - Page 148

148
1MRS751802-MUM
Protection Relay
Technical Reference Manual, Standard Configurations
REX 521
Fig. 9.2.1.-2 Connection overview diagram of the incoming feeder
CB
DC
REX521
CLOSE circuit breaker
1
0
0 1
OverviewInc
Circuit-breaker failure
protection
TRIP circuit breaker
Internal relay fault
Io>>> TRIP to breaker on
HV side of transformer
OC blocking signal
from the outgoing feeders
to the 3I>>> stage
OC blocking signal to
the HV relay (3I>> START)