As moisture condenses on the surface of the contaminated insulators, the electrical conductivity of the insulator surface increases, resulting in a leakage current on the surface and causing the insulators to fail. Condensation of moisture on the insulator surface occur
More
As moisture condenses on the surface of the contaminated insulators, the electrical conductivity of the insulator surface increases, resulting in a leakage current on the surface and causing the insulators to fail. Condensation of moisture on the insulator surface occurs due to the mechanism of radiation cooling, mainly in the early mornings of winters. In this case, the temperature of the insulator surface is lower than the dew point. In this paper, a sample of real fine dust collected from the dust center and chemical analysis and measurement of electrical conductivity in the wet state were performed. By simulating a 230-kV contaminated composite insulator in COMSOL Multiphysics software, the magnitude of leakage current was obtained and verified by an experimental test. Also, using heat transfer governing relations, the temperature of the insulator surface during the leakage current flow, was determined and compared with the images captured by the thermo-vision camera during the test. The results show that the leakage current and the surface temperature of the insulator increase with increasing the conduction and thickness of the contamination layer and consequently the probability of insulator failure also increases. Experimental testing shows that simulation of insulators with finite elements-based commercial software can be a reliable method for pre-analysis of insulators.
Manuscript profile
