Streamer inception and propagation in rape-seed oils and mineral oils

Abstract

Rape-seed oils prove to be good insulating liquids suitable for the use in high-voltage apparatus. In order to compare the breakdown behaviour of rape-seed oils with mineral oils, investigations with lightning and switching impulse voltage have been carried out. Due to the differing chemical structure, streamers in rape-seed oils show differing properties with respect to inception voltage, field strength, propagation velocity and structure. Nevertheless some similarities still remain e.g. polarity effect and streamer modes. Both, similarities and differences will be discussed in this contribution.