P.4.5
Date Code 20151029 Protection Manual SEL-411L Relay
Autoreclosing and Synchronism-Check
One-Circuit-Breaker Autoreclosing
and E3PT2 are deasserted, a single-pole reclose follows a single-pole trip;
when these SEL
OGIC control equations are asserted, only three-pole tripping
and reclosing result (see Trip Logic and Reclose Sources).
Single-Pole Mode
Figure 4.10 shows the one circuit breaker single-pole autoreclose cycle
79CY1. The cycle starts when Relay Word bit SPARC asserts. The recloser
waits as long as 10 cycles for the circuit breaker to open (indicated by Relay
Word bit SPO) and then begins timing SPOID (Single-Pole Open Interval
Delay) when the circuit breaker opens. After single-pole open interval time
SPOID expires, the relay recloses the circuit breaker if supervisory condition
SP1CLS (Single-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.
SPRCD Reclaim Timing
If the circuit breaker closes, the recloser starts timer SPRCD (Single-Pole
Reclaim Time Delay). The recloser determines subsequent state transitions
during reclaim timing according to the status of Relay Word bit SPLSHT
(Single-Pole Reclose Last Shot). When SPLSHT is asserted, the recloser
forces all subsequent relay trips to three-pole only mode.
SPLSHT Asserted (Last Shot). The recloser exits the 79CY1 state via three
methods while SPLSHT is asserted:
➤ If no further trip conditions occur, the recloser goes to the reset
state BK1RS after reclaim timer SPRCD expires.
➤ 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 (E3PR1 is logical 0, for
example) the recloser exits the 79CY1 cycle state and goes to
the lockout state BK1LO.
SPLSHT Deasserted (Single-Pole Shot Remains). The recloser
exhibits four possible state transitions when SPLSHT is not asserted:
➤ If no further trip conditions occur, the recloser goes to the reset
state BK1RS after timer SPRCD expires.
➤ If a single-phase fault occurs while the SPRCD reclaim timer is
timing, the recloser asserts SPARC for single-pole initiate
conditions and returns to the beginning of the 79CY1 cycle
state; the recloser increments the shot counter and begins the
next open interval timer.
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