Detection of intense partial discharge of epoxy insulation in sf6 insulated equipment using carbonyl sulfide

摘要

Basin insulators in gas insulated switchgear (GIS) are prone to failure by partial discharge (PD). Insulation diagnosis using gas analysis method has advantages of strong anti-interference ability and high detection precision. This paper reports a new characteristic gas Carbonyl Sulfide (COS) for the detection of PD in epoxy insulators of GIS. The generation of COS is verified by experiments with trace gas detection technique. Experimental results indicate that COS is generated only when the intensity of PD is strong enough to cause flashover on the epoxy insulators. The corresponding production mechanisms of COS have been clarified using quantum chemistry calculations. To assess the PD level using COS, the relationship between discharge power and growth law of the concentration of COS is obtained from the experiments, which indicates that COS could be used as an effective characteristic gas to diagnose epoxy solid insulation of GIS concerning high energy discharge.