An Automatically Reclosing Breaker for Co-ordinating Distribution Systems

The increasing spread of distribution systems in which fault protection is afforded by fuses has resulted in long outages and high maintenance costs. Excellent coordination is possible with modern fuses, but their inability to differentiate between a permanent and a temporary fault results in frequent outages and costly service trips. A new automatically reclosing circuit breaker with pronounced inverse time current tripping characteristics makes possible an improved radial distribution system in which outage and maintenance are reduced to a minimum. The effectiveness of coordination is increased to a point where an outage is confined to the immediate neighborhood of a permanent fault. Service trips are no longer necessary unless there is a permanent fault condition to be removed from the system.