| Because of the advantages of miniaturization, high reliability, easy maintenance and long maintenance cycle, GIS has been widely applied in substations of 110kV and above. However, various defects inevitably exist in the GIS due to the problems occurred in the process of assembly, manufacturing material selection, transportation and installation. Therefore, some technical means must be taken to detect and process GIS defects and risks early, which can reduce even avoid the risk of equipment failure.In this paper, entity platform and simulation model of 220kV GIS are established to simulate failure based on GIS UHF and ultrasonic PD detection technology. The characteristics and development regulation of signal spectrum of the UHF and ultrasonic PD under 13 kinds of typical PD defects are studied. We also built the transfer relationship of pulse current signal and PD signal of UHF and ultrasonic under two kinds of defects. The differences of UHF PD signal collected by internal and external sensors under four typical defects are analysed, which provided necessary technical support for the selection of bandwidth of internal and external UHF sensor. The paper analysed the characteristics and mode of transmission of UHF and ultrasonic PD interference signal and put forward four targeted interference suppression measures. The positioning method of UHF and ultrasonic PD signal is studied mainly including UHF time difference precise positioning method and ultrasonic grid strength positioning method. Finally, the paper introduced several site detection and application examples of different voltage levels. |
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