CF3I混合气体比例及放电参数分析

Analysis on CF3I Mixed Gas Proportion and Discharge Parameters

CF3I气体是一种极具潜力的SF6替代气体。为研究CF3I混合气体的最佳比例及电气特性,首先根据CF3I气体饱和蒸气压方程计算其液化条件,采用两项近似的Boltzmann方程求解三种CF3I混合气体在不同混合比下的电子能量分布及电离和吸附系数,并计算混合气体的折合有效击穿场强及协同效应指数。结果表明:三种混合气体的绝缘强度都随CF3I气体比例增加而增加,但混合气体的适用范围会随CF3I比例增加而减小;在相同混合比例时,CF3I-CF4及CF3I-N2混合气体的绝缘能力较强,CF3I-CO2的协同系数更高,电场均匀度对CF3I-N2及CF3I-CO2的绝缘能力的影响相对较小。综合考虑,N2更适合作为CF3I的缓冲气体,15%~30%CF3I比例的混合气体有较高的实际应用价值。

CF3I gas is a promising SF6 alternative gas.To study the optimal proportion and electrical characteristics of CF3I gas mixture,the liquefaction conditions of CF3I gas were calculated according to the saturated vapor pressure equation of CF3I gas.Two approximate Boltzmann equations were used to solve the electronic energy distribution,ionization coefficient,and attachment coefficients of three sorts of CF3I gas mixtures in different mixing ratios,and the equivalent effective breakdown field strength and synergistic effect index of the gas mixture were calculated.Results show that the insulation strength of the three sorts of gas mixtures increased with the increase of the CF3I gas ratio,but the application range of the gas mixtures decreased with the increase of the proportion of CF3I gas;at the same proportion of CF3I-CF4 and CF3I-N2,the insulation capacity of the gas mixtures was stronger,the number of the coordination coefficient of CF3I-CO2 was higher,and the influence of the electric field uniformity on the insulation capacity of CF3I-N2 and CF3I-CO2 was relatively small.In overall,N2 is more suitable as the buffer gas of CF3I,and the mixture of 15%~30%CF3I is recommended with higher practical value.