Laboratory tests of self-cleaning properties of polluted high-voltage insulators

The ability of insulators in a polluted environment to benefit from rain washing may significantly influence their service performance. A number of laboratory tests designed to assess self-cleaning properties were applied to a selected group of insulators. Orders of merit based on various criteria have been compared and found to differ with variations in test procedure. It is concluded that no single test can be prescribed at this time. It is recommended that future laboratory investigations be based on an analysis of data on the rain washing of insulators in service and in natural-pollution testing stations.