Isotope Tracing Experiment on the Mechanism of O2 on the Over-Thermal Decomposition of SF6

In gas-insulated equipment, partial over-thermal faults may occur due to poor contact and other reasons. The main insulation medium SF₆ may decompose under over-thermal conditions and produce harmful products such as SO₂ and HF, which can damage the equipment and reduce the insulation strength of the equipment. The method of decomposition component analysis can monitor the operating status of equipment without interference from machinery, noise and optics, and provide early warning or reminder of faults, but the premise is that the decomposition mechanism of SF₆ must have been fully and in-depth understood. In the decomposition process of SF₆, O₂ has a significant effect, but the mechanism of the effect is still unclear. Based on the isotope tracing method, this paper uses ¹⁸O₂ instead of ordinary O₂ for overheating experiments. Through the quantitative detection of the labeled products in the product and the abundance of ¹⁸O isotope in the products, the effect of O₂ on the formation of the main decomposition products was analyzed. The work makes the reaction process and mechanism of SF₆ with trace oxygen under over-thermal conditions basically clear, which provides an important theoretical basis for on-line monitoring and fault diagnosis of equipment based on chemical analysis methods.