A vertical-flow compressed-air circuit breaker and its application on a 132-kv power system

The compressed-air circuit breaker for indoor power-house service is becoming very popular. However, its use for high-voltage outdoor service is still in the field-trial stage. Several high-voltage porcelain-clad circuit breakers of American design are now in service, and their performance is being watched carefully. A 138-kv 1,500,000-kva three-pole breaker has been installed at the Kittanning substation of the West Penn Power Company. Before installation its interrupting ability was checked to 5,900 amperes with full 132 kv on a single-pole unit and on a circuit with a transient recovery rate of 3,100 volts per microsecond. The mechanical operation was tested with the breaker in a heavily iced condition at −14 degrees Fahrenheit. The air-supply system was tested at −4 degrees Fahrenheit, and both were found to operate satisfactorily.