Risk assessment of free moving particles in GIS using spectral and partial discharge analysis

Moving particles occurring in SF/sub 6/ gas-insulated switchgear can result in breakdown of the gaseous insulation. Therefore, it is important to trace such defects in time and to determine their risk for a possible breakdown. For this risk analysis process, the following four steps have to be taken into account: detection, location, identification and risk assessment of the defect. In this contribution, the UHF method has been used to detect insulation defects. Time-of-flight measurements can be used to locate the defect. The identification is an essential part for risk analysis of defects. Different methods can be applied based on spectral analysis or phase-resolved PD pattern analysis.