Development and application of a novel partial discharge on-line monitoring system for GIS

Different defects in gas insulation substation (GIS) cause several types of partial discharge (PD). A novel on-line PD monitoring technique for GIS is described in this paper. An external sensor is adopted to detect the PD signal and has a wide frequency band. Two kinds of measurement method are used for PD signal acquisition, and high performance hardware units are also employed in order to reflect the true PD characteristics. Based on the idea of combining statistical analysis and high frequency analysis, the analysis level is improved. The developed PD on-line monitoring system has been operating at one 110 kV GIS substation. The results show that the system is effective