P.4.16
SEL-411L Relay Protection Manual Date Code 20151029
Autoreclosing and Synchronism-Check
Two-Circuit-Breaker Autoreclosing
The relay loads the corresponding circuit breaker settings into the leader
Relay Word bits (LEADBK0, LEADBK1, and LEADBK2). If there is no
leader (no circuit breaker is active), the relay loads a logical 0 into LEADBK1
and LEADBK2, and a logical 1 into LEADBK0.
Follower Logic
The FBKCEN SELOGIC control equation, Follower Breaker Closing Enable,
defines the conditions necessary for the follower breaker to reclose.
The relay selects the follower as follows:
➤ If Circuit Breaker BK1 is the leader and Circuit Breaker BK2 is
not locked out, then Circuit Breaker BK2 is the follower.
➤ If Circuit Breaker BK2 is the leader and Circuit Breaker BK1 is
not locked out, then Circuit Breaker BK1 is the follower.
➤ If fewer than two circuit breakers are in service (NBK0 or
NBK1 is asserted), then there is no follower.
The following three Relay Word bits describe which circuit breaker is the
follower:
➤ FOLBK0, No Follower Breaker
➤ FOLBK1, Follower Breaker = Breaker 1
➤ FOLBK2, Follower Breaker = Breaker 2
If there is no follower (in the case of only one circuit breaker, for example),
the relay loads a logical 0 into the follower SEL
OGIC control equation
FBKCEN.
Dynamic Selection of Leader and Follower Circuit Breakers
The recloser dynamically selects the leader and follower circuit breakers
during the reclose cycle. The relay calculates the leader in the ready (reset)
state. At the start of the reclose cycle, the relay freezes this calculation and
sets circuit breaker designations. The leader/follower designation can
dynamically change in the cycle if the leader circuit breaker goes to lockout
and FBKCEN is asserted.
Set the initial leader/follower designation and follower close conditions with
settings SLBK1 (Lead Breaker = Breaker 1), SLBK2 (Lead Breaker =
Breaker 2), and FBKCEN (Follower Breaker Closing Enable). Table 4.5
shows the permutations of these settings.
Table 4.5 Dynamic Leader/Follower Settings (Sheet 1 of 2)
SLBK1 SLBK2 FBKCEN Comments
0 0 0 BK1 is the leader; BK2 is the leader only if BK1 LO
and BK2 is closed. BK2 will not close as the follower
upon successful close of leader BK1.
0 0 1 BK1 is the leader; BK2 is the leader only if BK1 LO
and BK2 is closed. BK2 will close as the follower if
BK1 LO after BKCFD. BK2 will close as the follower
upon successful close of the leader BK1.
0 1 0 BK2 is the leader; BK1 is the leader only if BK2 LO
and BK1 is closed. BK1 will not close as the follower
upon successful close of leader BK2.
To Next Page
Loading...
