A Line of 115-Kv through 460-Kv Air-Blast Circuit Breakers

Part I discusses a line of outdoor air-blast circuit breakers which has been developed for ratings of 115 kv through 460 kv. The breakers are of modular, or building-block, design, which allows the user to stock fewer spare parts and substantially reduces the personnel training problem. The breakers are expected to reduce the outage time of high capacity circuits for maintenance and inspection. They are rated to handle the high recovery rates encountered during power faults on transmission lines of high capacity systems. Part II discusses the utilization of a new design of gas-insulated current transformer by the air-blast breakers. Design details facilitate obtaining satisfactory protective relaying with current transformers on only one side of the interrupter contacts with a resulting substantial reduction in cost.