Sel SEL-421 - Page 208

R.2.40
SEL-421 Relay Reference Manual Date Code 20111215
Auto-Reclosing and Synchronism Check
Auto-Reclose Logic Diagrams
Figure 2.15 Two Circuit Breakers Three-Pole Cycle State (79CY3) When E79 := Y1 (continued)
12
3
6
9
12
3
6
9
12
3
6
9
C
D
A
Send Follower
to Lockout
Lockout
(BKnLO)
To Beginning
of 79CY3
NBK2
NBK1
No
No
Timed Out
Follower Breaker
Close Supervision
Timer (BKnCLSD)
BKR Close Failure
Timer (BKCFD)
3PARC
Time Between
Breaker (TBBKD)
To Beginning
of State
To Beginning
of State
3PARC
3PARC
Yes
Is the Follower Closed?
Has the Follower Closed?
Is Follower Closing
Enabled (FBKCEN = 1)?
Is the Leader in
the Lockout State?
Have Follower Close
Supervision Conditions
Been Met (3PnCLS)?
Is the Follower
Closed?
Determine Active
Breakers in Scheme
Issue Follower
CLOSE Command
LEADBKR=L/O
FOLBKR=L/O
Determine Leader
and Send Leader
to Lockout State
To Reclaim
Stage
Is the Leader in
the Lockout State?
Yes
Yes
Yes
Yes
Yes
FBKCL
Yes
No
No
No
No
No
D
Timing
Timed Out, or
3-pole reclosing
disabled for
follower breaker
(E3PRn = 0)
Timing
Timed
Out
Send Follower
to Lockout (BKnLO)
To Reclaim
Stage
Send Follower
to Lockout
Lockout
(BKnLO)
D
Leader To
Reclaim Stage
D
To Reclaim
Stage