A device similar to a reclosure that acts as a bypass switch for faulty sections of a transmission or distribution network. Sectionalizers remain open, not allowing energy to pass until a line goes dead, perhaps due to the tripping of a breaker or reclosure. When the primary circuit is broken, the sectionalizer switches energy flow to another circuit, allowing energy to flow on a parallel path around the section with the fault. The use of sectionalizers insures that power can continue to flow to critical points on a grid even when downed lines or other serious faults interrupt the primary transmission paths to those points.
See also:reclosure, circuit breaker, grid