Evaluation of Long-Term Boiling Water Immersion as Artificial Aging Test of Silicone Rubber Insulators

Abstract

Our country IRAN have long coastal area with length of more than 1830 km. Utility companies with 30 years of experience in using polymeric insulators in this very heavy polluted area. Operational history in these areas indicates many insulating problems. With the advancement of polymer insulation technology, the utilities want to select the longest life insulators for these areas. Laboratory studies accelerated testing of polymer insulators is the only available method to investigate the trend of insulator degradation during the aging process, because it takes a long time for noticeable changes and signs of aging to appear on insulators in the power grid. Different methods such as salt-fog, UV and boiling water are used to test artificial aging, each method has advantages and disadvantages. In our experience, boiling water is used as a low-cost method in compared to the other methods especially salt fog test. The aim of this research was to determine a shorter method for evaluation of SR insulators. In this paper, the accelerated aging of polymer insulators using salt-fog and boiling water immersion tests are investigated. During and after the aging test, the polymer insulator's electrical quality is analysed using leakage current measurement tools, partial discharge, and hydrophobicity. Surface changes are also analysed by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX), Thermo Gravimetrical Analysis (TGA), and Fourier Transform Infrared Spectroscopy (FTIR) both qualitatively and quantitatively.