R.2.7
Date Code 20111215 Reference Manual SEL-421 Relay
Auto-Reclosing and Synchronism Check
One-Circuit-Breaker Auto-Reclosing
3PLSHT Asserted (Last Shot). The recloser exits the 79CY3 state via
two methods while 3PLSHT is asserted:
➤ If no further trip conditions occur, the recloser goes to the reset
state BK1RS after reclaim timer 3PRCD expires.
➤ If a fault occurs during the 3PRCD reclaim time, then the
recloser exits the 79CY3 cycle state and goes to the lockout
state BK1LO.
3PLSHT Deasserted (Three-Pole Shot Remains). The recloser
exhibits three possible state transitions when 3PLSHT is not asserted:
➤ If no further trip conditions occur, the recloser goes to the reset
state BK1RS after timer 3PRCD expires.
➤ If a fault occurs during the 3PRCD reclaim time, then the
recloser asserts Relay Word bit 3PARC if all three-pole reclose
conditions are satisfied (E3PR1 is logical 1, for example) and
returns to the beginning of the 79CY3 cycle state; the recloser
increments the shot counter and begins the next open interval
timer.
➤ If a fault occurs during the 3PRCD reclaim time, and the three-
pole reclose conditions are not satisfied (E3PR1 is logical 0, for
example), the recloser exits the 79CY3 cycle state and goes to
the lockout state BK1LO.
Lockout State from 79CY3
The recloser goes to lockout (BK1LO) when the number of trips exceeds the
maximum number of shots (N3PSHOT), supervision condition 3P1CLS fails
to assert in BK1CLSD time, Relay Word bit 3POLINE asserts (for a circuit
breaker manual opening), the circuit breaker fails to close within BK1CFD
time, or any time Relay Word bit 79DTL asserts.
Single- and Three-Pole Mode
The single- and three-pole mode (SPAR/3PAR) uses elements of both the
single-pole mode (SPAR) and the three-pole mode (3PAR). Reclosing begins
after a single-pole trip in the single-pole cycle 79CY1 with a valid SPARC as
described in Single-Pole Mode on page R.2.5. The recloser closes the circuit
breaker and proceeds to the reclaim timer SPRCD. If a fault occurs during the
SPRCD reclaim time and SPLSHT is asserted, then the recloser asserts Relay
Word bit 3PARC if all three-pole reclose conditions are satisfied. Upon
asserting 3PARC, the recloser exits the 79CY1 cycle state and goes to the
beginning of the three-pole auto-reclose cycle state 79CY3. The recloser
proceeds through the 79CY3 state and exits this state as described in Three-
Pole Mode on page R.2.6.
Three-Pole Priority
If a single-pole auto-reclose cycle 79CY1 is in progress and the relay receives
an initiation for three-pole reclosing 3PRI, the recloser immediately starts a
three-pole auto-reclose cycle 79CY3.
To Next Page
Loading...
