Evaluation of long-term performance of polymeric insulators for 22 kV overhead distribution lines

The authors have developed EVA polymeric insulators for 22 kV overhead distribution lines. Compared to conventional ceramic insulators, these newly devised insulators are characterized by their smaller size, lighter weight and lower production costs. Evaluation has been made into their long-term insulation performance in outdoor environments at both an accelerated aging test and an outdoor exposure test. Results of leakage current measurements and examinations of surface conditions showed no increase in leakage current or problems with use even with the emergence of erosion on the surface. A sample exposed over 23,784 hours in outdoor environment showed less degradation than one exposed over 1,500 hours in the EdF test, displaying the qualities of a virgin sample. In light of these results, it could be confirmed that the proposed polymeric insulators demonstrate sufficient insulation performance for a long period in actual outdoor environments.