Diagnostic Technique of Gas Insulated Substation by Partial Discharge Detection

To make more reliable operations of Gas Insulated Substation (GIS), the detecting methods of internal irregularities from outside of enclosure before major insulation failures occure are required. Internal irregularity may cause a partial discharge, then the methods to detect the partial discharge chemically, mechanically, electrically and optically, are developed and those methods are applied to GIS model simulating the intemal irregularities and GIS in field operation. Investigation leads to the excellent results that those developed methods are able to be applied for GIS to confirm the reliability.