Model for calculation of flashover characteristics on polluted insulating surfaces under DC stress

This paper is devoted to the high voltage insulators pollution phenomena under DC stress. Basing on an analytical propagation criterion of the discharge on polluted insulating surfaces that we established elsewhere and by using an electrical equivalent circuit, we elaborate a predictive model allowing to determine the critical parameters characterizing the development of the discharge such as the flashover voltage, the current, the arc length and its resistance and the time lag to flashover. The instantaneous propagation velocity of the surface discharge is determined using energetic considerations. Two simple models of insulators are considered: plane and cylinder. It is shown that the simulated results given by the model are in good accordance with the experimental ones. The proposed model is discussed with regards to those reported by other investigators