On the stochastic nature of SF/sub 6/ partial discharges close to onset conditions

Discharges in compressed pure SF/sub 6/ were produced in a plane-point-plane electrode configuration. The present report focuses on the pulse characteristics, as observed by recording real-time discharge frames via a fast digitizer. Sampling by frame of a duration of typically 1 ms with time resolution of 1 ns, has given access to the relation between consecutive pulses. Results obtained for the negative DC corona at 500 kPa are presented. Discharge characteristics closeby corona threshold were overexamined in detail. The experimental approach, in conjunction with the rendered-possible analyses, allowed to unravel very distinctive features associated with the discharge events.