Studies on high temperature vulcanized silicone rubber insulators under arid climatic aging

Abstract

In recent times, high temperature vulcanized (HTV) silicone rubber (SIR) insulators featuring several advantages, have gained importance over conventional ceramic and glass insulators. However, environmental stresses and electrical discharge activities degrade their superior performance therefore long term reliability of polymeric insulators is still under investigation. In the present work, arid climate aging experiments are carried out on SIR and effects of dry thermal exposure on composite insulators are investigated. Hydrophobicity recovery phenomenon for contaminated polymeric insulator sheds is reported with elevated temperature and a method proposed for achieving uniformity in pollution layer is also highlighted. Furthermore, Fourier transform infrared (FTIR) spectroscopy, X-Ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), Thermo-Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) techniques are utilized to assess and analyze the changes in the material properties. The consequence of arid heating on tensile strength of SIR is evaluated. Also the dry flashover studies are carried out to discern the concerns related to the effects on thermally aged SIR insulators due to sudden overvoltages occurring in transmission lines.