Investigation of leakage current and electric field of polymeric insulator with ring-shaped contamination under ice conditions

Different environmental conditions such as pollution, rain, and frost affect the performance of polymeric insulators. In cold climates, insulators may become frozen, resulting in non-uniform distribution of potential and electric field around the insulator. Non-uniform distribution of potential and electric field along the insulator in turn cause problems such as erosion and flashover. Also, due to the wind direction in cold regions, the pollution layer accumulates non-uniformity on the insulator surface. This paper investigated the effect of ice layer with different configurations in combination with ring-shaped contamination, which is more common in cold regions, on the insulator surface to obtain the electric field distribution and leakage current of a 20 kV polymeric insulator. For this purpose, software based on finite element method (FEM) was used. Experimental test for evaluating the leakage current analysis of ring-shaped polluted insulator under ice condition was done in a laboratory clean fog chamber. The results of experimental data and the proposed simulated models were compared and validated. The results revealed that parameters such as increasing the freezing layer and its intensity, continuity of the freezing structure and electrical conductivity of the ice layer would enhance the amplitude of the electric field and leakage current, increasing the probability of flashover. Also, in the combination of ring-shaped contamination layer and freezing, the parameters of the ice layer are more influential than the contamination layer on the electrical behavior of the insulator.