Analysis of characteristic of natural pollution test and artificial simulation method

Pollution flashover has serious impact on power system and jeopardizes the safety of its operation. Many measures to avoid pollution flashover have been taken by the utilities through long term experience, while the mechanism of pollution flashover remains further research. Artificial pollution test is an effective method to estimate the electrical performance of the insulation system, but its equivalency to the natural pollution test has not been verified. Study on the natural pollution insulators on transmission line in Jiangsu Province, China, is presented in this paper. Possible explanations of the difference between the artificial pollution test and natural pollution test are proposed by comparing pollution flashover performance of artificial pollution insulators with the natural pollution insulators. A new method to apply natural pollution insulators is presented, with which leakage current and flashover voltage of artificial pollution insulators and natural pollution insulators are acquired. Comparison on the SEM structure of natural and artificial pollution is also taken to analyze the wetting properties of them. It is found that due to the compactness of the natural pollution, the Moisture rate of natural pollution is lower than that of artificial pollution, which leads lower leakage current and increased flashover voltage in the same conditions. In this paper, artificial pollution of non-uniform ESDD distribution has been used to simulate natural pollution and some conclusion has been made.