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6.6
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Autoreclosing
One-Circuit-Breaker Autoreclosing
➤
If a multiphase fault occurs during the SPRCD reclaim time, then the
recloser asserts Relay Word bit 3PARC if all three-pole reclose
conditions are satisfied (E3PR1 is logical 1, for example) and
proceeds to the autoreclose three-pole cycle state 79CY3.
➤
If a multiphase fault occurs during the SPRCD reclaim time, and the
three-pole reclose conditions are not satisfied (E3PR1 is logical 0, for
example), the recloser exits the 79CY1 cycle state and goes to the
lockout state BK1LO.
Lockout State From 79CY1
The recloser goes to lockout (BK1LO) when any of the following occur:
➤
The number of trips exceeds the maximum number of shots
(NSPSHOT).
➤
Supervision condition SP1CLS fails to assert in BK1CLSD time.
➤
Relay Word bit 3POLINE asserts (for a circuit breaker manual
opening).
➤
The circuit breaker fails to close within BKCFD time.
➤
Any time Relay Word bit 79DTL asserts.
Three-Pole Mode
shows the one circuit breaker autoreclose cycle 79CY3. The cycle
starts when Relay Word bit 3PARC asserts. The recloser checks SEL
OGIC
control
equation 79SKP at this point to determine whether to increment the shot counter.
The recloser waits indefinitely for the circuit breaker to open, as indicated by
Relay Word bit 3POLINE. The recloser begins timing 3POID1 (Three-Pole Open
Interval 1 Delay) when the circuit breaker opens. After the open interval time
3POID1 expires, the relay asserts Relay Word bit BK1CL to reclose the circuit
breaker if supervisory condition 3P1CLS (Three-Pole BK1 Reclose Supervision)
is satisfied within the duration of timer BK1CLSD (BK1 Reclose Supervision
Delay).
At the reclose command, the recloser starts timer BKCFD (Breaker Close Failure
Delay). If the circuit breaker fails to close, the recloser goes to lockout (BK1LO)
after timer BKCFD expires.
3PRCD Reclaim Timing
If the circuit breaker closes, the recloser starts timer 3PRCD (Three-Pole
Reclaim Time Delay). The recloser determines subsequent state transitions
during reclaim timing according to the status of Relay Word bit 3PLSHT (Three-
Pole Reclose Last Shot).
3PLSHT Asserted (Last Shot)
The recloser exits the 79CY3 state via one of the following two methods while
3PLSHT is asserted:
➤
If no further trip conditions occur, the recloser goes to the reset state
BK1RS after reclaim timer 3PRCD expires.
➤
If a fault occurs during the 3PRCD reclaim time, then the recloser
exits the 79CY3 cycle state and goes to the lockout state BK1LO.
Summary of Contents for SEL-421-4
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