Sel 411L - Table 4.11 Example Two: Initial Reset State; Table 4.12 Example Two: Final Reset State

P.4.20
SEL-411L Relay Protection Manual Date Code 20151029
Autoreclosing and Synchronism-Check
Two-Circuit-Breaker Autoreclosing
Reset State
Prior to receiving initiation for a three-phase fault, the autoreclose logic resets
for both circuit breakers. At the start of the reclose cycle, Relay Word bits
LEADBK1, FOLBK2, and NBK2 are asserted (see Table 4.11).
When BK1 successfully recloses, BK2 closes as the follower after timer
TBBKD (Time Between Breakers for ARC).
If BK1 goes to lockout during a reclose cycle (after BKCFD time), then BK2
will close as the follower. After timer 3PRCD (Three-Pole Reclaim Time
Delay) expires, the recloser enters the reset state for BK2 (BK2RS). The
recloser dynamically recalculates the leader and follower circuit breakers.
BK2 becomes the leader with Relay Word bits LEADBK2, FOLBK0, and
NBK1 asserted (see Table 4.12). When BK2 becomes the leader, the recloser
immediately issues the CLOSE command to BK2 and does not add any
additional SPOID or 3POID interval time.
Table 4.11 Example Two: Initial Reset State
Relay Word Bit Description Logical State
NBK0 No Active Breakers in Reclose Scheme 0
NBK1 One Breaker Active in Reclose Scheme 0
NBK2 Two Active Breakers in Reclose Scheme 1
LEADBK0 No Leader Breaker 0
LEADBK1 Leader Breaker = Breaker 1 1
LEADBK2 Leader Breaker = Breaker 2 0
FOLBK0 No Follower Breaker 0
FOLBK1 Follower Breaker = Breaker 1 0
FOLBK2 Follower Breaker = Breaker 2 1
Table 4.12 Example Two: Final Reset State
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