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6.22
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Autoreclosing
Two-Circuit-Breaker Autoreclosing
Example Four: Input Selection of Leader
illustrates a circuit breaker-and-a half configuration for this particular
example. The leader and follower selection settings are shown in
cuit Breaker BK1 is out of service for maintenance and Disconnect Switch 1 is
open.
defines the logical state of the autoreclose logic for this example prior
to the initiation of an autoreclose cycle. These conditions are frozen during an
autoreclose cycle. The relay autoreclose logic can unfreeze these conditions if the
relay receives another initiation.
Enable Autoreclose Logic for Two Circuit Breakers
Three-Pole Trip Circuit Breakers
The initial settings necessary to enable autoreclose for two three-pole trip circuit
breakers are shown in
.
Table 6.17
Leader/Follower Selection
Setting Label
Setting
SLBK1
IN106 (Disconnect 1 a contacts)
SLBK2
IN107 (Disconnect 2 a contacts)
FBKCEN
0
Figure 6.4
Leader/Follower Selection by Relay Input
Table 6.18
Two Circuit Breakers: Circuit Breaker BK1 Out of Service
Relay Word Bit
Description
Logical State
NBK0
No Active Breakers in Reclose Scheme
0
NBK1
One Breaker Active in Reclose Scheme
1
NBK2
Two Active Breakers in Reclose Scheme
0
LEADBK0
No Leader Breaker
0
LEADBK1
Leader Breaker = Breaker 1
0
LEADBK2
Leader Breaker = Breaker 2
1
FOLBK0
No Follower Breaker
1
FOLBK1
Follower Breaker = Breaker 1
0
FOLBK2
Follower Breaker = Breaker 2
0
Bus 1
(Leader)
Line
to IN106 to IN107
Out of Service
(maintenance)
Bus 2
BK2
BK1
Summary of Contents for SEL-421-4
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