Determination of Streamer Diameter in Insulating Oil

摘要

Exact modeling of streamer propagation requires precise knowledge of their geometry. Earlier evaluations of shadowgraph photographs revealed diameters as low as approximately 25 μm, an energetic balance yields even lower values. To ascertain the geometric condititions, in a point-plane configuration with an electrode distance of 120 mm, pre-discharge phenomena in transformer oil were investigated up to 200 kV alternating voltage. The evaluation revealed that the streamers have a mean diameter of only approx. 12 μm which is significantly less than the previously estimated values.