Developing of 550 kV 1-break GCB. I. Investigation of interrupting chamber performance

The interrupting chamber for a 550 kV 1-break gas blast circuit breaker (GCB) is developed. To cope with voltages and interrupting capacities of nearly double per break compared with 2-break GCBs, the shape of the interrupting chamber was optimized, and an interrupting chamber scheme using arc energy is employed. Small-current interrupting performance is improved by selecting a nozzle shape with pressure fluctuations due to a supersonic flow at the downstream side of the nozzle and by taking into account the dielectric recovery characteristics. By using an interrupting chamber scheme utilizing arc energy, the opening speed is increased by minimizing the reaction due to pressure rises in the puffer chamber in small-current interruptions, or the pressure is sharply raised due to the effect of arc energy in large-current interruptions. The nozzle shape is also optimized for a large-current interruption by improving the efficiency of treating hot gas.<
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