Auto-reclose closes a line breaker again after a protection trip, once a dead time has passed long enough for the fault arc to deionise: typically 0.3 to 1 second for single-shot schemes on transmission and several seconds between shots on distribution. Most overhead line faults, such as lightning flashovers or clashing conductors, are transient, so reclosing restores supply without a crew visit. A permanent fault drives the breaker to lockout after the final shot.
Feeder 12 tripped and auto-reclosed twice in the storm, the second shot held so it was probably branches in the wires.
Also heard as
- autoreclose
- reclosing
- AR
- 79
Related terms
Blink
Momentary outage customers see when an upstream breaker or recloser trips and recloses on a passing fault.
Flashover
Disruptive discharge over or around insulation that creates a short circuit through the air.
Distance protection
Line protection that measures impedance to a fault and trips fastest for faults close to the relay.
86 relay
Lockout relay that latches after a serious trip and holds breakers open until someone resets it by hand.