P.4.13
Date Code 20151029 Protection Manual SEL-411L Relay
Autoreclosing and Synchronism-Check
Two-Circuit-Breaker Autoreclosing
After three-pole open interval time 3POID or 3PFOID expires
➤ and E79 := Y, the recloser attempts to close the leader breaker,
as discussed below (first checking the supervisory condition
3PnCLS)
➤ and E79 := Y1, the recloser checks if the leader breaker is open.
If open, it attempts to close the leader breaker, as discussed
below (first checking the supervisory condition 3PnCLS). If the
leader breaker is closed (it never opened at the outset), the
recloser skips the leader breaker close logic and attempts to
close the follower breaker, as discussed further below (first
checking for two active breakers and an open follower breaker,
before starting timer TBBKD [Time Between Breakers for
ARC])
The recloser closes the leader if supervisory condition 3PnCLS (Three-Pole
BKn Reclose Supervision) is satisfied within the duration of timer BKnCLSD
(BKn Reclose Supervision Delay).
At the leader CLOSE command, the recloser starts timer BKCFD (Breaker
Close Failure Delay). If the leader fails to close, the recloser sends the leader
to lockout BKnLO after timer BKCFD expires. If the leader closes within the
BKCFD time, the recloser goes to 3PRCD (Three-Pole Reclaim Time Delay)
reclaim timing if NBK1 is asserted, or prepares to close the follower circuit
breaker if NBK2 is asserted.
To close the follower circuit breaker, the recloser checks for two active circuit
breakers in the scheme. If NBK2 is asserted, the recloser checks for a three-
pole open on the follower and starts timer TBBKD (Time Between Breakers
For ARC). When TBBKD expires, the recloser closes the follower breaker if
FBKCEN (Follower Breaker Closing Enable) is asserted and supervisory
condition 3PnCLS is satisfied within the duration of timer BKnCLSD. At the
follower CLOSE command, the recloser starts timer BKCFD (Breaker Close
Failure Delay). If the follower fails to close, the recloser sends the follower to
lockout after timer BKCFD expires. If the leader circuit breaker is not in
lockout, the recloser begins timing 3PRCD reclaim time for the leader.
If the follower breaker closes successfully, the recloser starts the 3PRCD
(Three-Pole Reclaim Time Delay) timer if 79BRCT (Block Reclaim Timer) is
not asserted.
3PRCD Reclaim Timing
The recloser determines subsequent state transitions during reclaim timing
according to the status of Relay Word bit 3PLSHT (Three-Pole Reclose Last
Shot).
3PLSHT Deasserted (Three-Pole Shot Remains)
The recloser exhibits two possible state transitions when 3PLSHT is not
asserted:
➤ If no further trip conditions occur and timer 3PRCD expires,
the recloser returns to the reset states BKnRS.
➤ If a fault occurs while the 3PRCD reclaim timer is timing, then
the recloser asserts 3PARC if all three-pole initiate conditions
are satisfied and goes to the beginning of the 79CY3 cycle. The
recloser then recalculates and freezes the number of active
circuit breakers, the leader, and the follower. The recloser then
increments the shot counter and begins the next open interval
timer.
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