Ag表面对SF_(6)初级分解产物氧化反应的影响作用研究  

Study on the Effect of Ag Surface on Oxidation of SF_(6)Primary Decomposition Products

作　　者：李昊天 曾福平[1] 颜伊鸣 朱可馨 姚强 唐炬[1] Li Haotian;Zeng Fuping;Yan Yiming;Zhu Kexin;Yao Qiang;Tang Ju(School of Electrical Engineering and Automation Wuhan University,Wuhan 430072 China;State Grid Chongqing Electric Power Company Electric Power Research Institute,Chongqing 401123 China)

机构地区：[1]武汉大学电气与自动化学院,武汉430072 [2]国网重庆市电力公司电力科学研究院,重庆401123

出　　处：《电工技术学报》2024年第9期2841-2850,共10页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金(51877157);湖北省杰出青年基金(2020CFA097)资助项目。

摘　　要：运行经验显示SF_(6)在气体绝缘开关设备(GIS)中的热稳定性低于预期,GIS内部的金属表面可能对SF_(6)初级分解与次级反应具有显著的影响作用,但作用机理尚不明晰。该文基于密度泛函理论获得了O_(2)在Ag表面的解离-吸附构型,并建立了低氟硫化物与Ag表面O原子的反应模型,初步揭示了GIS过热故障状态下SF_(6)初级分解产物在Ag表面的氧化反应机理;基于过渡态理论和反应动力学理论,计算获取了界面反应的能垒和反应速率常数,并与气相反应对比,分别确定了三种低氟硫化物的氧化反应路径及其主要场所,并分析了Ag表面对反应的促进/抑制作用机制。结果显示,Ag表面可显著促进SOF_(4)与SOF_(3)的产生,但不利于SF2的表面氧化反应。Operational experience shows that the thermal stability of SF_(6)in the gas-insulated equipment is lower than expected,and the metal surface inside the equipment may have a significant effect on SF_(6)primary decomposition and secondary reactions,but the mechanism is not yet clear.First,it is necessary to study how the O2 molecule dissociates and provides the reaction system with O atoms,which requires high energy;second,it needs to reveal the reasons for the significantly lower stability of SF_(6)than expected in the actual fault state;third,it is necessary to investigate in depth the mechanism of the metal surface inside the GIS on the generation process of important characteristic products.Among the metal materials used in GIS,silver is usually plated on the internal contacts,electrical connections and other locations to lower the contact resistivity where the local over-thermal faults occasionally occur.In this case,the Ag surface is in direct contact with SF_(6)gas and other impurity gases,while the mechanism of the interfacial interaction is not known and needs to be studied.First,the adsorption configuration of O2 on the Ag surface is obtained based on density functional theory,and the reaction model of low-fluorine sulfides with the O atom on Ag surface is established,which initially reveals the mechanism of oxidation reaction of SF_(6)primary decomposition products on the Ag surface under GIS over-thermal fault state;Second,based on transition state theory and reaction kinetic theory,the energy barrier and reaction rate constant of interfacial reaction are calculated and compared with the corresponding gas-phase reaction,respectively.Last,the main reaction sites of the oxidation reaction paths of the three low-fluorine sulfides are identified separately,and the promotion/inhibitory mechanism of the reaction by the Ag interface is analyzed.(1)The presence of the Ag interface enables the SOF4 generation reaction,which is otherwise difficult to occur in the gas-phase space at both room temperature and super

关 键 词：气体绝缘开关设备 六氟化硫 过热分解 银表面 氧化反应 

分 类 号：TM855[电气工程—高电压与绝缘技术]