Suitability of thermoplastic polymer used as insulator for HV apparatuses

Improving the recyclability of the high voltage apparatus is a major concern of the manufacturers. In this paper, the suitability of thermoplastic polymer used as support insulator in high voltage gas insulated substation is presented in this paper. Among the possible candidates, a semi-crystalline thermoplastic polyethylene-terephtalate was selected and investigated in terms of the chemical structure and the morphology as well as the basic characteristics such as mechanical and electrical characteristics are reviewed for the virgin material. The effect of the temperature on the dielectric strength is also investigated. In view of extremely promising results, it is worthwhile studying the evolution of the material properties under operating conditions. In that sense, mechanical creepage curves are given. It is also shown that the main electrical properties of the material are affected neither by aging under used SF₆ nor by combined thermo-electrical ageing. As an application, we present the manufacturing of plate insulator dedicated to the new 72.5 kV three phase F35 substation insulation.