Streamer initiation and propagation in insulating oil in weakly non-uniform fields under impulse conditions

This paper deals with the investigation of prebreakdown phenomena in insulating oil in weakly nonuniform fields of rodplane geometries with gaps up to 100 mm under impulse voltages of both polarities up to 700 kV. As with the point-plane configuration, the rod-plane geometry shows a decrease of the time to breakdown with increasing voltage rate-of-rise. At a specific rate, a significantly shorter breakdown time is observed both for positive and negative polarities. Beyond this discontinuity range breakdown time decreases again but with lower rates