The influence of cavity´s parameters within polyimide material on partial discharge

Partial Discharge (PD) is one of the most important factors, which causes insulation breakdown of electrical equipment. The characteristic of partial discharge (PD) occurred within the polyimide material is significantly influenced by the parameters of the defect site. The paper made a mode of polyimide material with single void in it based on Finite Element Analysis (FEA) software. In this model, the shape of the cavity and the pressure in it is constant. The characteristics of PD by different cavity diameters and different location of the cavity are analyzed. Modeling of the partial discharge activity, electric field distribution was worked out in different cavity´s parameters. The mechanism of electric field distribution under the sinusoidal voltage and influence on PD of different cavity parameters within the polyimide material was worked out. The results show that with the increase of cavity diameters, the electric field has a slight decrease in the cavity, as the cavity surface is nearer to the electrode. And the electric field distortion is obvious with the cavity located out-of-Centre. This is due to the influence of the electrode. The PD activity significantly depends on the cavity´s parameters within the polyimide material.