Automating motor-operated air-breaker switches

The detection and clearing of transformer faults are intimately connected to the primary switching that is available. Breakers are used both as locations for the current transformers to detect a fault and define the zone of protection and as a way of clearing the fault. The use of so many circuit breakers (CB) is usually not justified economically. As an alternative, motor-operated air-breaker switches (MOAB) instead of CBs are commonly used. A MOAB cannot interrupt a fault and usually can be opened only if the adjacent transmission line segment is de-energized. The growth and increased complexity of power system configurations has led to arrangements of MOABs with transformers and power transmission lines. This causes a difficult situation when relay engineers coordinate operation of relay sequence and MOABs. This article presents a solution for such a difficulty. The solution utilizes a local area supervisory protection (LASP) system to collect voltage and current data and then share data among the associated relays.