Evaluation of surface degradation of polymer insulating materials related to leakage current

Artificial aging tests are performed using test rods made of silicone rubber (SR) and ethylene propylene diene monomer (EPDM), based on the rotating wheel dip test (RWDT) method and the salt chamber test (SFCT) method. Aspects of surface degradation are evaluated. It is concluded that the surface degradations of polymer insulating materials are directly related to the partial discharge, and that the cumulative charge of leakage current on the surface of test specimens is useful in evaluating degradation aspects. It is also determined that the RWDT is useful in comparing certain materials regarding their resistance to tracking and erosion, and that the SFCT is competent for evaluating surface characteristics