P.4.10
SEL-411L Relay Protection Manual Date Code 20151029
Autoreclosing and Synchronism-Check
Two-Circuit-Breaker Autoreclosing
Two-Circuit-Breaker Autoreclosing
Modes
The autoreclose logic operates in three modes:
➤ Single-pole mode (SPAR)
➤ Three-pole mode (3PAR)
➤ Single- and three-pole mode (SPAR/3PAR)
Relay settings ESPRn (Single-Pole Reclose Enable—BKn) and E3PRn
(Three-Pole Reclose Enable—BKn) determine the autoreclose mode (see
Recloser Mode Enables). These settings are inputs to the recloser initiation
Relay Word bits SPARC (Single-Pole Reclose Initiate Qualified) and 3PARC
(Three-Pole Reclose Initiate Qualified); see Figure 4.8 and Figure 4.9.
SPARC asserts when all necessary conditions to begin a single-pole
autoreclose cycle are satisfied (ESPRn, for example) and the recloser receives
a single-pole reclose initiation SPRI (see Figure 4.8). Relay Word bit 3PARC
asserts when all necessary conditions to begin a three-pole autoreclose cycle
are satisfied (E3PRn, for example) and the recloser receives a three-pole
reclose initiation 3PRI (see Figure 4.9).
Other recloser settings include the initial recloser settings (see Enable
Autoreclose Logic for One Circuit Breaker) and the trip logic enable settings
E3PT, E3PT1, and E3PT2. When SEL
OGIC control equations E3PT, E3PT1,
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 4.12 and Figure 4.13 show the two circuit breaker single-pole
autoreclose cycle 79CY1 when E79 := Y and E79 := Y1, respectively. The
cycle starts when Relay Word bit SPARC 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 for an SPO (Single-Pole Open) condition for either the
leader or follower, and waits as long as 10 cycles for the circuit breakers to
open. If the leader or follower shows a single-pole open inside the 10-cycle
window, the recloser proceeds to timing SPOID (Single-Pole Open Interval
Delay). The recloser goes to lockout if the circuit breakers fail to open (no
close attempts follow). If an evolving fault results in a three-pole trip
condition that asserts 3PARC, then the recloser exits the 79CY1 cycle and
goes to the three-pole cycle 79CY3. When E79 := Y1, a Single-Pole Open
Interval Supervision Condition (SPOISC) must be satisfied before the recloser
can proceed to timing SPOID. If the supervisory condition is not met within
the duration of timer SPOISD (Single-Pole Open Interval Supervision Delay),
the recloser goes to lockout.
After single-pole open interval time SPOID expires, the recloser closes the
leader if the single-pole open condition is still in effect and supervisory
condition SPnCLS (Single-Pole BKn Reclose Supervision) is satisfied within
the duration of timer BKnCLSD (BKn Reclose Supervision Delay). If the
leader circuit breaker has more than one pole open at the end of the SPOID
time, the recloser sends the leader to lockout BKnLO.
NOTE: In the following discussion,
n is 1 or 2 for Circuit Breaker BK1 or
BK2.
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