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. The breaker was installed on the most active line of the West Penn Power Company system. During the three months following its installation it had 41 operations, five of which were on faults. Its operation to date has been satisfactory in every detail, and it is hoped that this new device will meet operating requirements and reduce materially the time outage for servicing such apparatus.