A test method for determining the outdoor lifetime of polymer overhead transmission line insulators

A test method has been developed to evaluate the outdoor durability of polymer high voltage insulators. The surface discharges responsible for aging are reproduced as accurately as possible in a test chamber while specially designed microprocessor instrumentation continuously monitors the electrical behavior of the test specimens. Erosion rates can be determined in units of weight loss per coulomb of discharge activity for simple specimen shapes. Practical insulator shapes can also be tested. Combining the indoor test results with short term results from a microprocessor monitored outdoor test rack yields an estimate for the outdoor lifetime of commercial insulator designs.