Simulation and Mechanism Study of Cavity Discharge Under Pulsed Electric Field

The high voltage devices are easy to produce tiny cavities and discharge under pulsed electric field, which aggravate the deterioration of material insulation. In order to explore the specific mechanism and influencing factors in the process, this paper builds a two-dimensional plasma simulation model of cylindrical medium wrapped spherical cavity under nanosecond pulsed electric field and analyzes the spatiotemporal evolution process of discharge through the changes of electron density, positive ion density, surface charge density and electric field intensity. Besides, the rule of the effect of discharge products and pulse frequency on cavity discharge are studied. The simulation results show that the cavity discharge mainly occurs at the front and tail of the pulse. The discharge current will rise rapidly after the cavity breakdown. When surface charges accumulate to a certain extent, the opposite electric field will cause the gas voltage to decrease and finally the discharge ends near the pulse flat area. When the pulse voltage is applied, the number of ozone molecules continues to increase. The generation rate is faster at the front and tail time, which is more corrosive to dielectric materials. When the pulse frequency is increased, the gas is more likely to discharge at a lower voltage and the peak discharge current decreases. The number of ozone molecules increases within a certain period of time. This paper provides a certain reference for improving the insulation properties of materials.