Investigation of natural and artificial contamination on various types of insulators

This paper presents an investigation on the performance of 11kV porcelain and composite insulator under AC voltage when subjected into natural and artificial contamination. Three types of porcelain and one type of composite insulators are located in different contamination of industrial areas for natural pollution. The contaminants are coal and quarry dust. According to IEC 60507, the solid layer method is used for artificial pollution, the pollutants samples are collected from various industrial areas to simulate conductive and inert materials. By using even rising method, the average flashover voltage can be calculated. Pollution levels were measured by using NSDD method. For natural contamination, the NSDD values are varied with respect to environmental conditions and the NSDD remains constant in artificial contamination. Comparing the test results, composite insulator can withstand more on both regions due to higher leakage distance than others. The poor performances are obtained on disc insulator in natural pollution conditions.