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.

在气体绝缘设备中，由于接触不良等原因，可能会出现局部过热故障。主要绝缘介质SF ₆在过热条件下会分解，产生SO ₂、HF等有害产物，会损坏设备，降低设备绝缘强度。分解成分分析的方法可以在不受机械、噪声和光学干扰的情况下监测设备运行状态，并提供故障预警或提醒，但前提是SF ₆的分解机制必须已经全面深入明白了。在SF ₆、O _{2的分解过程中}有显着效果，但其作用机制尚不清楚。本文基于同位素示踪法，采用¹⁸ O ₂代替普通O ₂进行过热实验。通过对产物中标记产物和产物中¹⁸ O同位素丰度的定量检测，分析了O ₂对主要分解产物形成的影响。该工作使SF ₆与微量氧在过热条件下的反应过程和机理基本清晰，为基于化学分析方法的设备在线监测和故障诊断提供了重要的理论依据。