Simulation Model of Streamer Discharge in Dielectric Liquid under Positive Nanosecond Pulse

The study of streamer discharge is of great significance for understanding and exerting the insulating properties of dielectric liquids. In this paper, an electrothermal hydrodynamic model describing the streamer discharge process in dielectric liquids is established. The generation and dissipation mechanisms of electrons, positive ions and negative ions in streamer discharge are considered, and the convection diffusion of three carriers is considered. The equations couple the Poisson equation and the thermal diffusion equations to describe the streamer discharge process in a dielectric liquid under a positive nanosecond pulse. It is found that the streamer discharge can be divided into two processes, an initial process and a development process. The rapid voltage rising edge at the initial process causes the shrinkage of the streamer front; the magnitude of the electric field strength in front of the streamer front, the velocity of streamer, the shape of the streamer front, and the temperature rise during the development process of streamer are basically constant.