Simulation on Surface Charge Accumulation Process of Epoxy Insulator in Air

Most of the HV power equipment with gas-solid insulation suffers a lot from the surface charge accumulation due to corona discharge. The existence of surface charge distorts the local electric field and leads to surface flashover faults in extreme situations. As a result, it is important to Fig. out the mechanism of surface charge accumulation process. In this paper, a simulation model combining both the plasma hydrodynamics and charge trapping-detrapping process was built. The simulation results have a good agreement with the experimental data, the main summary is as follows: In the surface charge accumulation process, the corona discharge intensity increases first and then decreases with time. The curves of the surface potential distributions have different shapes at different times, the central value goes up rapidly with time in the beginning and finally reaches saturation. Surface charges exist in the skin layer of epoxy insulator, some of them may be captured by traps while transporting away under built-in electric field.