Triggered Breakdown In SF/sub 6/ And SF/sub 6/ Mixtures

A comprehensive study has been carried out into the breakdown characteristics (jitter, delay, dV/dt) of pulsed charged triggered spark gaps filled with SF/sub 6/ gas mixtures, for voltages up to 200kV. The influence of the combination of trigger voltage polarity and main gap voltage polarity has been investigated and the results are discussed with reference to the mechanism of discharge initiation and arc formation. A similar study has been carried out with mixtures of SF/sub 6/ and air, N/sub 2/ and He. The results emphasise the importance of trigatron voltage polarity and also reveal that several SF/sub 6/ gas mixtures possess improved switching characteristics compared to those of SF/sub 6/, without a reduction in withstand voltage. The delay time to breakdown results for SF/sub 6/ and SF/sub 6/ gas mixtures have been recorded at several pressures and compare well with predicted results according to Martin (1).