High Power Short Circuit Studies On A Commercial 420 kV 60 kA Puffer Circuit Breaker

The development of a heavy duty puffer circuit breaker is described along with the results of some high power tests during which pressure and arc radiation were measured. The commercial circuit breaker utilises two breaks and a partial duoflow and is rated at 420 kV, 60 kA rms. The measurements reported covered the peak current range 10-80 kA, current decay rates of 14-24 A/us, arcing durations of 3-15 ms and nominal background pressures of 3.5 -6.9 bar. The radiation measurements have indicated the effectiveness of the partial duoflow in restricting metal vapour entrainment into the arc gap. The pressure measurements have provided an insight into factors affecting the circuit breaker performance and facilitated comparison with performance data published by other authors.