Modeling of DC Critical Flashover of Transmission Line Insulator Long String under Windward/Leeward Side non-Uniform Pollution Condition

Abstract

In areas with seasonal wind direction, transmission line insulator surface pollution layer will distribute nonuniformly between windward and leeward sides, performing like a fan shape. Previous studies found that this kind of nonuniform pollution lowers the flashover gradient of insulator. In this paper a continuous work intended for predicting de critical flashover voltage of long insulator string under windward/leeward side non-uniform pollution was presented. This research includes the establishment of a parallel resistance model considering multi-arc, a prediction of dc critical flashover voltage basing on the proposed model, and the verification through various test data from previous artificial tests. Also the corresponding discussion concerning the variation rule of surface residual pollution layer resistance, arc propagation process under different non-uniformities was made. Research results indicate that the proposed model is validated to be feasible to predict the dc flashover voltage of long string insulator with given pollution non-uniformity K and T. Under windward/leeward side non-uniform pollution, the residual pollution layer resistance decreases, causing the electrical property reduction of insulator string.