Schweitzer Engineering Laboratories SEL-421-4 - Page 995

6.19
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Autoreclosing
Two-Circuit-Breaker Autoreclosing
Block Reclosing With Enable Settings
To block BK2 as leader use the enable settings; set ESPR2 := NBK2 and
E3PR2 := NBK2. With these enable settings BK2 never becomes the leader cir-
cuit breaker.
Example Two: BK2 as Successful Follower and Dynamic Leader
Another example is similar to the first with SLBK1/SLBK2/FBKCEN at 1/0/1
(see Table 6.10).
Reset State
Prior to receiving initiation for a three-phase fault, the autoreclose logic resets for
both circuit breakers. At the start of the reclose cycle, Relay Word bits
LEADBK1, FOLBK2, and NBK2 are asserted (see Table 6.11).
Table 6.9 Example One: Reset State After Reclaim Time
Relay Word Bit Description Logical State
NBK0 No Active Breakers in Reclose Scheme 0
NBK1 One Breaker Active in Reclose Scheme 1
NBK2 Two Active Breakers in Reclose Scheme 0
LEADBK0 No Leader Breaker 0
LEADBK1 Leader Breaker = Breaker 1 0
LEADBK2 Leader Breaker = Breaker 2 1
FOLBK0 No Follower Breaker 1
FOLBK1 Follower Breaker = Breaker 1 0
FOLBK2 Follower Breaker = Breaker 2 0
Table 6.10 Leader/Follower Selection
Setting Label Value
SLBK1 1
SLBK2 0
FBKCEN 1
Table 6.11 Example Two: Initial Reset State
Relay Word Bit Description Logical State
NBK0 No Active Breakers in Reclose Scheme 0
NBK1 One Breaker Active in Reclose Scheme 0
NBK2 Two Active Breakers in Reclose Scheme 1
LEADBK0 No Leader Breaker 0
LEADBK1 Leader Breaker = Breaker 1 1
LEADBK2 Leader Breaker = Breaker 2 0
FOLBK0 No Follower Breaker 0
FOLBK1 Follower Breaker = Breaker 1 0
FOLBK2 Follower Breaker = Breaker 2 1