Influence of polarity and pressure on the SF6 decomposition characteristics under DC voltage

A comparative study of the decomposition characteristic of SF6 under direct voltage with different polarities and pressure was conducted in this paper. The changes of discharge capacity, discharge energy and decomposition product concentrations were observed and analyzed in detail. The results indicate that SF6 decomposition characteristics are closely related to polarity and pressure. Discharge energy and concentrations of decomposition products under positive polarity are obviously higher than those under negative polarity, which can be explained by different discharge energy and distribution characteristic of space charges. Concentrations of typical products including SOF2, SO2F2, and SO2 decrease with the increasing pressure according to the decreasing effective dissociation volume.