Variable-voltage application for insulator pollution tests

The speed and precision of salt fog contamination testing of insulators is improved using stepwise voltage application to give numerous flashovers in a single test. A similar technique for the clean fog method, which gives comparable results to conventional tests at constant voltage, is proposed. Valuable information on the performance of naturally contaminated ceramic insulators, directly comparable to that for artificial contamination, can also be obtained. With the same technique, the performance of naturally or artificially aged and contaminated nonceramic insulators can be studied and the aging process monitored as it proceeds