R.2.19
Date Code 20111215 Reference Manual SEL-421 Relay
Auto-Reclosing and Synchronism Check
Two-Circuit-Breaker Auto-Reclosing
Lockout State
Circuit Breaker BK1 fails to close when the first three-pole open interval
expires and goes to lockout. Circuit Breaker BK2 goes to lockout. Table 2.8
defines the logical state of the auto-reclose logic at this point.
Reset State After Reclaim Time
Circuit Breaker BK2 is manually closed and now becomes active as the leader
after 3PMRCD (Manual Close Reclaim Time Delay). Subsequent reclosing
occurs with BK2. Tab le 2. 9 defines the logical state of the auto-reclose logic
at this point.
Block Reclosing with Enable Settings
To block BK2 as leader use the enable settings; set ESPR2 := NBK2 and
E3PR2 := NBK2. With these enable settings BK2 never becomes the leader
circuit breaker.
Table 2.8 Example One: Lockout State
Relay Word Bit Description Logical State
NBK0 No Active Breakers in Reclose Scheme 1
NBK1 One Breaker Active in Reclose Scheme 0
NBK2 Two Active Breakers in Reclose Scheme 0
LEADBK0 No Leader Breaker 1
LEADBK1 Leader Breaker = Breaker 1 0
LEADBK2 Leader Breaker = Breaker 2 0
FOLBK0 No Follower Breaker 1
FOLBK1 Follower Breaker = Breaker 1 0
FOLBK2 Follower Breaker = Breaker 2 0
Table 2.9 Example One: Reset State After Reclaim Time
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
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