基于氧同位素示踪法的火花放电中O_2对SF_6分解气体形成的影响

Influence of O_2 on By-product of SF_6 Decomposition in Spark Discharge Test Based on Oxygen Isotope Tracer

六氟化硫气体(SF_6)因其良好的绝缘和灭弧性能,广泛应用于气体绝缘电气设备中。当SF_6气体绝缘电气设备发生放电故障时,SF_6气体将分解为低氟硫化物,这些低氟硫化物与混入SF_6气体中的杂质如水、氧气等进一步发生反应,产生具有剧毒强腐蚀性的SF_6分解衍生物。作为主要的气体衍生物,SO_2F_2、SOF_2、SO_2等氟氧化物是基于分解气体法的故障识别与诊断的标志产物。为此,文中提出了一种基于氧同位素示踪的SF_6分解气体分析方法。在一系列火花放电实验的基础上,通过注入不同含量的同位素氧气18O_2,分析火花放电中微量氧气对主要氟氧化物含量及其比值变化规律的影响,进而解释火花放电下主要氟氧化物的成因机制。

ASulfur hexafluoride （SF6） is one of the most commonly used insulating media in high-vohage electrical equipment because of its excellent insulation. Among electrical discharge faults, spark discharge is one of the most common types, often induced by poor contact of fixed metal shield or switch contacts. It is known that SF6 can decompose to lower fluorides of sulfur in electrical discharge, and these radicals will oxidize in the presence of water vapor or oxygen, resulting in the formation of decomposition by-products with strong toxicity and corrosivity. This paper proposes a method based on oxygen isotope tracer to observe the variations and to analyze the formations of the oxyfluorides, such as SO2F2, SOF2, and SO2. By injecting different concentrations of 18O2, a series of spark discharge experiments is carried out. Then, the concentration of the oxy-fluorides under different ratios of 18O2 to 16O2 （[18O2]/[16O2]） is obtained. Finally, the formation mechanisms of the oxyfluorides are discussed based on the experiments.