INVESTIGATION OF PARTIAL DISCHARGES IN SF6 USING A COMPUTER-BASED DATA AQUISITION SYSTEM

This paper describes investigations aimed at developing a new method of testing SF6 gas, from GIS, for impurities. The method involves observation and analysis of the properties and characteristics of corona discharge produced when an SF6 sample is subjected to the nonlinear electric field of a point-plane test geometry. These properties are sensitive to the presence of impurities and analysis of the discharges should provide information which allows some estimation of the impurity, perhaps even species and concentration. Preliminary to such development, this paper describes a number of experiments involving PD recording and analysis in SF6 samples contaminated by moisture. The results of the experiments indicate that statistical analysis of the data may provide possible means of impurity evaluation. To date, only a simple analysis has been used. More detailed analysis may provide better information.