Comparison of leakage current properties between polymeric insulators and porcelain insulators under salt polluted conditions

This report describes a comparison of leakage current properties between a polymeric insulator and a porcelain insulator subjected to salt polluted conditions. Exposure tests at a sea coast test site were carried out, and the leakage current of insulators, climate conditions, and salt deposit density were measured during the tests. Appearance of leakage current for the porcelain insulator was affected by the humidity and the salt deposition on the surface, but that for the polymeric insulator was related to rainfall. The hydrophobic surface of the polymeric insulator must play an important role in suppressing leakage current under the salt polluted conditions compared to the less hydrophobic surface of the porcelain insulator.