Numerical Simulation of Multi-Branching Positive and Negative Streamer Discharges Near the Oil-paper Interface in Dielectric Liquid During Pulsed Voltage

A multi-branching streamer discharge model of dielectric liquid is established by considering random fluctuations of carrier density in this article. The branching and propagation characteristics of positive and negative streamers in the oil-paper interface are investigated under impulse voltage by using the finite element method. Results show that the branch and electric field strength of positive and negative streamers significantly increased after contact with the paperboard. The development characteristics between positive and negative streamers are significant differences at the oil-paper interface. The secondary branches of the dominant branch of negative streamers are more obvious than that of positive streamers, resulting in the effect of the negative secondary branches on the development of negative streamers being more serious than that of positive streamers. In addition, the negative streamer branches are more likely to develop closer to the oil-paper interface than the positive streamer branches, which is in good agreement with the experimental results, and suggests the model can well simulate the morphology and development characteristics of positive and negative streamers at the oil-paper interface.