DEVELOPMENT OF 550KV 1-BREAK GCB .1. INVESTIGATION OF INTERRUPTING CHAMBER PERFORMANCE

The interrupting chamber for 550kV 1-break gas circuit breaker (GCB) w as developed. To cope with voltages and interrupting capacities of nea rly double per break compared with 2-break GCBs, the shape of the inte rrupting chamber was optimized, and an interrupting chamber scheme usi ng arc energy was employed. Small-current interrupting performance was improved by selecting a nozzle shape with pressure fluctuations due t o a supersonic flow at the downstream side of the nozzle and dielectri c recovery characteristics taken into account. By employing an interru pting chamber scheme utilizing arc energy, the opening speed is increa sed by minimizing the reaction due to pressure rises in the puffer cha mber in small-current interruptions or the pressure is sharply raised due to the effect of arc energy in large-current interruptions. The no zzle shape is also optimized for a large-current interruption by impro ving the efficiency of treating hot gas.