Quantitative analysis of the influence of regularity of SF6 decomposition characteristics with trace O2 under partial discharge

Abstract

To obtain the influence regularity of trace O 2 on SF 6 decomposition characteristics under partial discharge (PD) and establish the foundation of using SF 6 decomposed components to diagnose the insulation status of SF 6 electrical equipment, first, a series of PD decomposition experiments with different O 2 concentrations (%)were conducted on a special experiment platform. The variation regularity between the concentrations of characteristic components and the different content of O 2 were obtained quantitatively. Second, the correlation coefficient r testing method was applied to identify the associated influence of trace O 2 on the decomposed characteristic components and characteristic ratios. Based on this, an exponential regression model of the related characteristics was developed. Finally, the influence mechanism of trace O 2 on SF 6 decomposition progress was explained reasonably. The results show that under the PD caused by metal protrusion insulation fault without organic solid insulated materials, CO 2 , SO 2 F 2 , and SOF 2 were the mainly decomposed components in the specific range of trace O 2 . Although no obvious influences of the trace O 2 on the concentrations of CO 2 and SOF 2 as well as the ratio c(CO 2 )/c(SO 2 F 2 +SOF 2 ), it is notable that the trace O 2 is negatively and positively related to the concentration of SO 2 F 2 and the ratio c(SOF 2 )/c(SO 2 F 2 ), respectively. The exponential regression model can minimize the effect of trace O 2 on the fault diagnostic result when using SF 6 decomposed components.