Artificial-pollution test for high-voltage outdoor insulators

A new method of measuring the performance of an insulator subjected to pollution has been developed. A saline fog is produced in which the insulator will flash over at its working voltage. By reducing the salinity of the aqueous solution used for the fog, the maximum value at which the insulator will not flash over is obtained. This salinity is taken as the criterion of performance, and comparison with the results obtained by natural-pollution testing shows that it can be taken as a valid guide to the performance of the insulator in service conditions. The artificial-pollution method has been used as a research tool for comparative tests of insulators and is proposed for use as a standard test.