Sel 551 - Figure 2.13 SEL-551 Provides Overcurrent Protection for a Distribution Bus (Includes Fast Bus Trip Scheme)

2.13
Date Code 20110408 Instruction Manual SEL-551 Relay
Installation
SEL-551 AC/DC Connection Diagrams for Example Applications
Figure 2.13 SEL-551 Provides Overcurrent Protection for a Distribution Bus (Includes Fast Bus Trip Scheme)
The fast bus trip scheme is often referred to as a reverse interlocking or zone
interlocking scheme.
52A
C
B
A
TC
52
(-) Trip
Circuit
Breaker
Failure
Trip
Circuit
to Annunciator or RTU
Trip
Coil
(+)
(+)
(+)
86B
Out
Lock
86
(-)
SEL-551 Relay
IN
IC
IB
IA
IN2
IN1
ALARM
OUT4
OUT3
OUT2
OUT1
from Feeder Relays
(-)
(Fast Bus Trip Scheme)
BUS