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.