P.4.15
Date Code 20151029 Protection Manual SEL-411L Relay
Autoreclosing and Synchronism-Check
Two-Circuit-Breaker Autoreclosing
Figure 4.2 Multiple Circuit Breaker Arrangement
Choose Circuit Breaker BK1 as the leader and Circuit Breaker BK2 as the
follower. If Circuit Breaker BK1 is out of service (for maintenance, for
example), the relay can automatically make Circuit Breaker BK2 the leader.
The relay freezes the leader, follower, and number of active circuit breaker
designations during an autoreclose cycle. If the logic receives another reclose
initiation, the relay reevaluates the leader, follower, and number of active
circuit breaker designations. The logic considers a circuit breaker out of
service if the circuit breaker goes to lockout, and declares a circuit breaker to
be in service as soon as the circuit breaker closes and is no longer in lockout.
Leader Logic
Relay settings SLBK1 (Leader Breaker = Breaker 1) and SLBK2 (Leader
Breaker = Breaker 2) SEL
OGIC control equations determine the criteria for
relay selection of the active leader. Set SLBK1 := 1 to select Circuit Breaker 1
as the leader; set SLBK2 := 1 to select Circuit Breaker 2 as the leader. SLBK1
has priority over SLBK2; if you set both settings to 1 or both to 0, Circuit
Breaker 1 is the leader.
Circuit Breaker BK1 is the leader for the following conditions:
➤ BK1 is the only circuit breaker in service
➤ BK1 and BK2 are in service and BK1 is selected as the leader
(SLBK1 := 1)
➤ BK1 and BK2 are in service and the setting combination
SLB1 := 0 and SLBK2 := 1 is not in effect
Circuit Breaker BK2 is the leader for the following conditions:
➤ BK2 is the only circuit breaker in service
➤ BK1 and BK2 are in service and BK2 is selected as the leader
(SLKBK1 := 0 and SLBK2 := 1)
➤ If neither circuit breaker is in service, there is no leader.
The following three Relay Word bits describe which circuit breaker is the
leader:
➤ LEADBK0, No Breaker In Service
➤ LEADBK1, Leader Breaker = Breaker 1
➤ LEADBK2, Leader Breaker = Breaker 2
Bus 1
(Leader) (Follower)
Line
Bus 2
BK2
BK1
To Next Page
Loading...
