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

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.