A recloser is a self-controlled device for automatically interrupting and reclosing an AC circuit, with a predetermined sequence of opening and reclosing. Like a circuit breaker, a recloser can be used for

interrupting currents. The interrupting medium of a recloser is most commonly vacuum or oil. The recloser control can be electronic, electromechanical or hydraulic. A hydraulic recloser uses springs and hydraulic

systems for timing and actuation. In short, a recloser is a circuit breaker which is integrated with a relay and a reclosing control element.


Automatic reclosing is motivated by the fact that about 60-80% of all overhead distribution faults are temporary and last only a few cycles or a few seconds. For example, a branch may blow against a circuit and then fall to the ground. As a result, it becomes very attractive to reclose following an initial opening of the protection device.


Reclosers have many distribution applications:


• It can be used in the substation as feeder interrupters instead of circuit breakers. Reclosers are used more in smaller stations and circuit breakers more in larger stations.


• Three-phase reclosers can be used on the main feeder to provide necessary protection coverage on longer circuits, along with improved reliability.


• Reclosers are available as single-phase units, so they can be used on single-phase taps (laterals) instead of fuses.


• Another common application is in auto-loop automation schemes to automatically sectionalize customers after a fault.


• Three-phase reclosers are available that can operate each phase independently (so a single-phase fault will only open one phase)