A study of flashover voltage of artificially polluted porcelain disc insulator under natural fog conditions

The availability of cheap and reliable supply of electrical energy plays very important role in the economic development and social welfare of any society. 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. Therefore outdoor insulation cannot be selected without having knowledge of prevailing pollution severity. This paper reports results of artificial pollution tests that have been done with different contaminants. The choice of contaminants for use in the present artificial pollution test was done with respect to the occurrence of soluble and non-soluble salts in natural pollution conditions. 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 an increase in pH and conductivity of the contaminants lower 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.