Interrupter pressure measurement of a 252 kV SF6 circuit breaker

The transient pressure process, which determined the gas blasting in the interrupter of SF₆ circuit breaker, have attracted the attention of designer and developer for long time. In this investigation, a on-load SF₆ interrupter pressure measurement method was established with piezoresistive pressure transducer and insulating-tube. The pressures in the puffer cylinder, at the upstream, throat and downstream of nozzle have been measured. The difference of gas blowing characteristics between N₂ and SF₆ has been pointed out. The insulating-tube can effectively protect the pressure transducer from the high voltage and high temperature during on-load interrupting. It was found that the arc process can cause high frequency oscillations to superimpose upon the pressure waveforms during on-load interrupting.