Fractal simulation of breakdown in oil impregnated paper at pulsating DC voltage

The oil impregnated paper is one of the typical composite structure containing a large number of cavities, which are filled with insulating oil through oil impregnation. In this paper, the oil-impregnated paper structure is simplified and an electrical breakdown model is developed to describe the breakdown progress in oil impregnated paper at pulsating DC voltage. Based on the traditional WZ model, the space discharge and physical time are introduced in the proposed model. The influence of temperature is also investigated. The skeleton types of discharge structure, discharge velocity, and charge movement during the breakdown are simulated. The breakdown simulation results show that the conductivity variation of insulation paper is an important factor which reduces the breakdown voltage under pulsating DC voltage at high temperature.