Influence regularity of trace O6 on SF6 decomposition characteristics and its mathematical amendment under partial discharge

In order to build a solid engineering application foundation when using decomposed characteristic components to identify the internal insulation faults of SF₆ electrical equipment, this paper conducted serials of experiment about the influence of different trace O₂ on SF₆ decomposed components. The variation regularity of the accumulative concentration, relative formation rate, and ratio of the characteristic component (CF₄, CO₂, SO₂F₂, and SOF₂) with changing time was investigated. The dynamics theory of the chemical reaction was exploited to analyze the influence regularity of O₂ on the characteristic components. A mathematical model about the influence of O₂ on the characteristic ratio (C(CF₄)/C(CO₂), CCF₄+CO₂)/C(SOF₂+SO₂F₂) and C(SO₂F₂)/C(SOF₂)) was established. The results show that: the accumulative concentration and relative formation rate of CF₄, CO₂, SO₂F₂, and SOF₂ changes with the content of different trace O₂, but each variation regularity is different. As a result, it leads to different variation regularity of characteristic ratios. Besides, power function can depict the influence regularity of trace O₂ on the characteristic ratios and adjust the SF₆ decomposition characteristics of different O₂ content to a comparable standard, which can lay theoretical basis for diagnosing the insulation defects of the SF₆ electrical equipment.