电工技术学报2024，Vol.39Issue(19)：6145-6161,17.DOI:10.19595/j.cnki.1000-6753.tces.231394
CF3SO2F及其混合气体电弧等离子体粒子组分与物性参数计算
Calculation of Particle Composition and Physical Property Parameters of Arc Plasma Particles of CF3SO2F and Its Gas Mixtures
摘要
Abstract
Sulfur hexafluoride(SF6)is commonly used as an insulating gas in electrical equipment,but its high global warming potential(GWP)has led to efforts to seek for alternative gases.Reducing SF6 usage can significantly decrease greenhouse gas emissions,benefitting climate change mitigation and meeting the demand for eco-friendly electrical equipment in renewable energy.Previous research has identified potential environmentally friendly alternatives like C4F7N and C5F10O,but improvements are needed due to factors such as high liquefaction temperature,GWP values,and toxicity.Trifluoromethyl sulfuryl fluoride(CF3SO2F)has recently emerged as a highly promising replacement,exhibiting superior performance compared to SF6 and a much lower GWP of 3 678(around 15％of SF6's GWP).Thus,CF3SO2F shows excellent potential as a substitute for SF6 in insulation applications.Accurate calculations of CF3SO2F's particle composition and physical parameters at various temperatures are crucial for further studying its insulating properties and ability to extinguish arcs. This study delves into the particle composition of CF3SO2F gas and its mixture in arc plasma,wherein equilibrium compositions of the plasma within the temperature range from 300 K to 30 000 K were calculated employing the Gibbs free energy minimization method.By virtue of standard statistical thermodynamic equations and the Chapman-Enskog method,the variations of thermodynamic and transport parameters of the plasma versus temperature were computed for different atmospheric pressures and mixture ratios.Subsequently,the influence of different buffer gases on the CF3SO2F mixture system was explored,along with a comparison of relevant properties between CF3SO2F and other commonly used insulating gases such as SF6 and C4F7N.Finally,the thermal arc breaking capacity of CF3SO2F gas was comprehensively analyzed. The results of particle composition calculations for CF3SO2F-N2 mixtures show that as the temperature increases,larger molecules gradually decompose into smaller molecules and atoms.Above 8 000 K,the occurrence of primary and secondary ionization reactions can be observed for monatomic species,with the order of ionization peaks determined by their respective ionization energies.Furthermore,higher atmospheric pressure has a significant suppressive effect on particle dissociation and ionization reactions.The CF3SO2F-N2 mixture system exhibits four major specific heat peaks at approximately 2 500 K,7 000 K,16 000 K,and 30 000 K,which correspond to different primary reactions occurring under these temperatures.Interestingly,the physical properties show significantly distinct for mixed systems with different buffer gases at low temperatures,primarily due to the differences in the number of N2 and CO2 atoms.The decomposition process for N2 occurs in one step at 7 000 K,while CO2 undergoes a two-step decomposition at 3 000 K and 8 000 K,respectively.Computations of the transport parameters for different insulating gases reveal that the CF3SO2F system,which contains carbon(C)element,exhibits higher conductivity than SF6 between 3 500 K and temperatures below 10 000K.With regards to the thermal arc breaking capacity,100％SF6 possesses the strongest ability over CF3SO2F and C4F7N systems.Finally,the thermal arc interruption capabilities of CF3SO2F gas and other common insulating gases were analyzed under actual operating conditions(-25℃,6 atm).The results indicate that 100％SF6 exhibits a stronger thermal arc interruption capability.Additionally,the highest thermal arc interruption capability is observed in the 10％CF3SO2F-90％CO2 mixture system,where the ρcp peak is slightly higher than that of the 5％C4F7N-95％CO2 mixture system below the conductive temperature,while the opposite is true above the conductive temperature. The following conclusions can be drawn from the simulation analysis:(1)Higher atmospheric pressure effectively suppresses the decomposition and ionization reactions of CF3SO2F gas.(2)An increased proportion of CF3SO2F in the gas mixture leads to more intense decomposition reactions in the low-temperature region,and milder ionization reactions in the high-temperature region.(3)Compared to the CO2 pure gas system,N2 exhibits minimal decomposition processes below the conductive temperature,resulting in distinct differences in the thermodynamic properties and thermal arc interruption characteristics of the corresponding CF3SO2F mixture systems.(4)The ρcp index suggests that CF3SO2F possesses a stronger thermal arc breaking capacity than the commonly used insulating gas C4F7N.关键词
CF3SO2F/环保绝缘气体/等离子体/粒子组分/物性参数Key words
CF3SO2F/environmentally friendly insulating gas/plasma/particle composition/physical parameters分类
信息技术与安全科学引用本文复制引用
柯学,王安阳,刘伟,颜湘莲,王雯,郭宇铮,王俊..CF3SO2F及其混合气体电弧等离子体粒子组分与物性参数计算[J].电工技术学报,2024,39(19):6145-6161,17.基金项目
国家重点研发计划资助项目(2021YFB2401400). （2021YFB2401400）
