Electrical characterisation of a single creeping streamer in transformer oil

Potential distribution measurements along a guided creeping discharge using capacitive probes confirmed the existence of a mean potential gradient along the channel and of a well-defined potential of the streamer tip when it stops. They also revealed a universal behavior and a decrease of the gradient from the streamer tip to the needle. There is a finite potential gradient along the channel whose magnitude increases from the needle to the streamer tip and the final potential at the tip reaches a well-defined value. Comparison of the fields on the lateral surface and at the tips of the streamers, as well as of the mean field along the channel, demonstrates analogy between these single creeping streamers and filamentary streamers propagating in the bulk