Effect of contaminant pH and natural fog on naturally polluted porcelain disc insulator in northern region of India

Overhead power transmission lines cross regions which are different in environmental conditions. The reliable and uninterrupted operation of modern power system depends on reliable insulation. Outdoor insulation cannot be selected without having knowledge of prevailing pollution severity. This paper reports results of natural pollution tests that have been done at different locations. Flashover voltage (FOV) of porcelain disc insulator for different pH values and conductivity has been recorded to relate FOV with pH and conductivity of the contaminants. It is found that a decrease in pH and increase in conductivity of the contaminant lowers FOV of the insulators. Regular condition monitoring of porcelain insulators can be done using pH of the contaminants as an effective pollution severity indicator, it may further be used for devising proper maintenance schedule.