6.10
SEL-400 Series Relays Instruction Manual Date Code 20171006
Autoreclosing
Two-Circuit-Breaker Autoreclosing
External Recloser
If reclosing is performed by an external relay, assert SELOGIC control equations
E3PT and E3PT1 via a control input (for example):
E3PT := NOT IN104 Three-Pole Trip Enable (SEL
OGIC equation)
E3PT1 := NOT IN104 Breaker 1 3PT (SEL
OGIC equation)
Connect the external recloser single-pole trip output signal to IN104. Other exter-
nal recloser signals are required; consult the external recloser documentation for
interconnection with the relay.
Two-Circuit-Breaker Autoreclosing
Modes
The autoreclose logic can operate in one of three modes, depending upon the
relay reclose capabilities:
➤ Single-pole mode (SPAR)
➤ Three-pole mode (3PAR)
➤ Single- and three-pole mode (SPAR/3PAR)
NOTE: In the following discussion,
n=
1 or 2 for Circuit Breaker BK1 or
BK2.
Relay settings ESPRn (Single-Pole Reclose Enable—BKn) and E3PRn (Three-
Pole Reclose Enable—BKn) determine the autoreclose mode (see Recloser Mode
Enables on page 6.8). 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 6.9 and Figure 6.10. SPARC asserts
when all necessary conditions to begin a single-pole autoreclose cycle are satis-
fied (ESPRn, for example) and the recloser receives a single-pole reclose initia-
tion SPRI (see Figure 6.9). Relay Word bit 3PARC asserts when all necessary
conditions to begin a three-pole autoreclose cycle are satisfied (E3PRn, for exam-
ple) and the recloser receives a three-pole reclose initiation 3PRI (see
Figure 6.10).
Single-pole recloser settings also include the initial recloser settings (see Enable
Autoreclose Logic for One Circuit Breaker on page 6.8) 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 for Single-Pole Breaker
Applications on page 6.25).
Single-Pole Mode
Figure 6.13 and Figure 6.14 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
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