Partial discharge recognition through an analysis of SF6 decomposition products part 1: decomposition characteristics of SF6 under four different partial discharges

Partial discharge (PD) is usually aroused before the failure of gas insulated switchgear (GIS) caused by defects, which results in the decomposition of the SF₆ used as insulating gas. Analyzing SF₆ decomposition products can aid in PD detection. Before recognizing PD types by analyzing SF6 decomposition products, the decomposition characteristics of SF₆ under different types of PD should be investigated first. In this paper, a gas chamber and four typical types of artificial defects were designed to simulate the SF₆ decomposition phenomenon under PD in GIS. A gas chromatography system was established to detect SF₆ decomposition products. By selecting the chromatographic column, SF₆ decomposition products were successfully separated and their concentrations were measured. Numerous SF₆ decomposition experiments under four kinds of PD generated by four kinds of artificial defects were carried out and the SF6 decomposition products produced by each experiment were detected. The decomposition characteristics of SF₆ under the four defects were different in terms of decomposition amount, generation rate, and concentration ratio, among others. It is feasible to recognize the type of PD by analyzing SF₆ decomposition products.