Non-uniform Pollution Method and Pollution Flashover Characteristics of Transmission Line Insulators

At present, pollution of insulators in artificial contamination test is done by uniform smearing, but natural pollution, affected by wind, raining, insulator shape, pollution, pollutant particle size and other factors, is a non-uniform accumulation on the insulator surface, and the non-uniform contamination has an effect on the insulator U_50%. Based on a study of the natural pollution characteristics of insulators in multiple regions of a large area, different pollution characteristics of the upper and lower surfaces of different umbrella insulators are obtained, and a non-uniform artificial pollution method is proposed for the upper and lower surfaces of insulators based on the natural contamination characteristics. Non-uniform artificial contamination tests were carried out for the insulators under AC/ DC voltage, and the corresponding pollution flashover curves were obtained. The test results show that the contamination of the insulators by non-uniform pollution method is close to the actual operating conditions of insulators, and the testing results are more accurate and reasonable. It is concluded that the more non-uniform of the contamination on the upper and lower surfaces, the larger the U_50% value is, but the incremental amplitude of U_50% decreases and tends to be saturated. The main conclusions of this paper are of great significance for the optimization of insulator string length and type selection.