Research Of GIS Partial Discharge Detection Technology Based On Ultrasonic And Uhf Method

Gas Insulated Switchgear (GIS) is widely used in power system for its compact structure, small footprint,low engineering cost,reliable operation and Small amount of maintenance. It could lead to large area blackout and long maintenance time once a GIS equipment insulation accident happened which could cause huge direct and indirect economic losses.So it has important practical significance for finding early potential insulation defects of GIS then ensuring the safe operation of GIS equipment and the reliability of power supply by conducting a thorough research to the PD detection techniques of GIS.Firstly,the mechanism of GIS’s internal partial discharge and the typical defects of its discharge characteristics have been studied.secondly, a laboratory platform for simulating typical partial discharge defects of GIS has been set up.And then a large amount of ultrasonic and UHF PD signal detection map and data of typical defects have been obtained through the experiment.Finally,the rules and mapping characteristics of GIS’s four types of typical defects have been summarized.The feature parameters of ultrasonic PD pulse signals caused by different GIS insulation defects have been extracted by using fractal theory and time-frequency analysis theory.And classification of different GIS insulation defects has been achieved basing on the fuzzy c-means clustering algorithm.Eventually,Through analysing the frequency characteristics of the extracted parameters, the identifying criterion of insulation defects has been got which providing a theoretical and experimental basis for the pattern recognition of partial discharge in GIS.The validity and accuracy of the GIS ultrasonic wave, UHF PD detection method has been verified through the research and analysis with a actual case of Baoding power grid.And the realization method of PD on-line monitoring function of GIS substation equipment has been elaborated with an engineering case.Practical experience obtained can be used to guide the productive practice of power.