基于密度泛函理论的SF_6潜在可替代性气体介电性能分析

The Analysis of SF_6 Potential Alternative Gas Dielectric Strength Based on Density Functional Theory

基于密度泛函理论对SF_6可替代气体的介电性能进行研究,对影响气体介电强度的分子电离能及平均静态电子极化率进行计算,并采用回归分析方法得到气体介电强度与此两微观参数之间的相关性。由相关性的分析结果可知,随着分子电离能及平均静态电子极化率的增大气体的介电强度增强。据此,进一步研究分子电离能及平均静态电子极化率特性,分析发现这两个参量均与分子链长及分子中包含的官能团类型有关。研究结果表明:仅从耐电性能方面考虑,相对分子质量较大的氟化物有望代替SF_6成为新型绝缘气体,本文为SF_6可替代气体的筛选与设计提供了依据。

Based on the density functional theory(DFT),the dielectric properties of SF6 alternative gas was studied.The molecular ionization energies and average static electronic polarizability affecting the dielectric strength of gas were calculated,the correlation between gas dielectric strength and those two microscopic parameters was obtained by regression analysis.From the results of correlation,it can be seen that the dielectric strength of gas increases with increasing the molecular ionization energy and average static electronic polarizability.Therefore,the further studies on the characteristics of ionization energy and static average molecular polarizability were developed.The analysis found that both parameters are related to the molecular chain length and the type of functional groups contained in the molecules.The results indicate that only from dielectric strength consideration,the fluoride with large molecular weight is expected to replace SF6 as new insulation gas.This paper provides the basis for screening and designing of SF6 potential alternative gas.