Operating Mechanisms for High-Capacity High-Voltage Oil Circuit Breakers [includes discussion]

The operating mechanism of a power circuit breaker must give consistent and exacting performance under the most rigorous conditions. Therefore it is important to select the most suitable design for use with the new high-capacity high-voltage oil circuit breakers. Mechanism designs have changed over the years to match circuit-breaker and industry requirements. They now must be adapted to meet the requirements of these new circuit breakers which will require special consideration of certain characteristics: higher output, shorter instantaneous reclosing times with multiple-duty cycles, higher speed tripping, and increased reliability. This paper discusses the various methods available to obtain these objectives and illustrates the conclusions reached by describing a mechanism design which incorporates them and which already has found wide usage.