Identification of Failure Root Causes Using Condition Based Monitoring in Solid Insulations

Abstract

Most of the high voltage (HV) power equipment is made up with solid insulation like paper insulation, glass insulation, epoxy insulation etc. Among all the insulation material the paper insulation is the most ancient type of insulation used in cable and nowadays the commonly used insulating material is Cross linked Polyethylene (XLPE). The presence of impurities in the insulation system is one of the root causes of insulation failure as they are form a weak zone inside the healthy insulation system. Therefore, early identification of degradation process like formation of electrical tree structures inside such solid electrical insulation due to high voltage tress during its operating life is utmost requirement to prevent the electrical power equipment from a sudden and complete insulation failure. To study the growth mechanism of electrical tree structure inside the insulation with different applied high voltage a commonly used insulating material like XLPE and paper insulation in HV power cable are consider for this present work. This work also describes the ageing process by conducting the partial discharge (PD) test on the same insulating materials. Finally, the effect of PD on insulation i.e., formation of electrical tree structure on solid insulation was observed by using Scanning Electron Microscope (SEM) and analysed.