Sel SEL-421 - Two Circuit Breakers Three-Pole Cycle State (79 CY3) When E79:= Y1

R.2.39
Date Code 20111215 Reference Manual SEL-421 Relay
Auto-Reclosing and Synchronism Check
Auto-Reclose Logic Diagrams
Figure 2.15 Two Circuit Breakers Three-Pole Cycle State (79CY3) When E79 := Y1
12
3
6
9
12
3
6
9
79CY3
79CY3
Yes
Yes
Yes
No
No
(3PLSHT)
Timed Out
3 Pole Open Interval
Timer (3POIDn)
LEADBKR Closed
(by external means)
Close
Supervision
Delay (BKnCLSD)
3POLINE
Is Skip Shot
Asserted?
Has the Line
Opened 3 Pole?
Increment Shot.
Is Shot Count Greater
Than or Equal to the
Number of set Reclosures?
Breaker Close
Failure Timer (BKCFD)
Is Leader Allowed
to Close (3PnCLS)?
Is Leader Closed?
Issue Leader
CLOSE Command
Yes
No
Yes
Timing
12
3
6
9
No
Timing
Timed Out, or 3-Pole Reclosing
Disabled for Lead Breaker (E3PRn=0)
Timed
Out
LBKCL
C
A
Determine Active
Breakers in Scheme
NBK2
NBK1
Lockout
(BKnLO)
Lockout
(BKnLO)
A
Freeze
3PARC
3-Pole Reclose Initiation (3PARC)
from Ready States (BK1RS and/or
BK2RS) or from Single-Pole Reclose
Cycle State (79CY1)
3-Pole Reclose Initiation (3PARC)
while in 3-Pole Reclose Cycle
State (79CY3)
If 3-Pole Reclosing is disabled for Breaker n (E3PRn = 0), send
Breaker n to lockout (BKnLO). Recalculate Leader, Follower, and
Number of Active Breakers logic, then freeze calculations
No