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6.12
SEL-400 Series Relays
Instruction Manual
Date Code 20171006
Autoreclosing
Two-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 (E3PR
n
is logical 1, for example) and recalculates
the number of active circuit breakers, the leader, and the follower before
proceeding to the autoreclose three-pole cycle state 79CY3.
➤
If a multiphase fault occurs during the SPRCD reclaim time,
SPLSHT is not asserted, and the three-pole reclose conditions are not
satisfied (E3PR
n
is logical 0, for example) and the recloser exits the
79CY1 cycle state and goes to the lockout state BK
n
LO.
SPLSHT Asserted (Last Shot)
The recloser exits the 79CY1 state via three methods while SPLSHT is asserted:
➤
If no further trip conditions occur and timer SPRCD expires, the
recloser returns to the reset states BK
n
RS.
➤
If a fault occurs during the SPRCD reclaim time, then the recloser
asserts Relay Word bit 3PARC if all three-pole reclose conditions are
satisfied and proceeds to the autoreclose three-pole cycle state 79CY3.
➤
If a fault occurs during the SPRCD reclaim time and the three-pole
reclose conditions are not satisfied (E3PR
n
is logical 0, for example),
then the recloser exits the 79CY1 cycle state and goes to the lockout
state Bk
n
LO.
Lockout State From 79CY1
The recloser goes to lockout (BK
n
LO) when the number of trips exceeds the
maximum number of shots (NSPSHOT), supervision condition SP
n
CLS fails to
assert in BK
n
CLSD time, Relay Word bit 3POLINE asserts (for a circuit breaker
manual opening), the circuit breaker fails to close within BKCFD time, or any
time Relay Word bit 79DTL asserts.
Three-Pole Mode
and
show the two circuit breaker three-pole autoreclose
cycle 79CY3 when E79 := Y and E79 := Y1, respectively. The cycle starts when
Relay Word bit 3PARC asserts. The recloser freezes calculation of the number of
breakers, the leader circuit breaker, and the follower circuit breaker. Depending
on the calculation, the recloser asserts the appropriate Relay Word bits NBK0,
NBK1, NBK2, LEADBK0, LEADBK1, LEADBK2, FOLBK0, FOLBK1, and
FOLBK2. The recloser checks SEL
OGIC
control equation 79SKP at this point to
determine whether to increment the shot counter.
The recloser waits for 3POLINE to assert:
➤
if E79 := Y, 3POLINE asserts when both breakers (leader and
follower) open (see
➤
if E79 := Y1, 3POLINE asserts when at least one breaker (leader or
follower) opens (see
)
If 3POLINE asserts within the 3PRIH time delay, the recloser proceeds to timing
3POID1 (Three-Pole Open Interval 1 Delay). If 3POLINE fails to assert within
the 3PRIH time-delay setting, the recloser goes to lockout. If the 3PRIH
setting = OFF, the recloser will wait indefinitely for 3POLINE to assert before
proceeding to timing 3POID1. If SEL
OGIC
control equation 3PFARC (Three-
Pole Fast ARC Enable) is asserted, the recloser times the open interval time from
setting 3PFOID (Three-Pole Fast Open Interval Delay). When E79 := Y1, a
Three-Pole Open Interval Supervision Condition (3POISC) must be satisfied
Summary of Contents for SEL-421-4
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