A New Prediction Model of SF₆ Alternative Gases in Electrical Strength

Sulfur-Hexafluoride (SF₆) has been widely used for gas insulation in power industry. However, due to its high Global Warming Potential (GWP), considerable effort has been undertaken to find eco-friendly replacement gases but without significant success for decades. In the study of alternative gas searching, the large number of candidate alternative gases limits the searching approach by the experiments. And in this work, different prediction models for gas electrical strength proposed by different researchers with their respective advantages are compared and concluded. Moreover, a new efficient model is developed. According to a comprehensive sample set of 73 gas species, different molecular properties are calculated based on the density functional theory. Strong correlations between electrical strength and above predictors are obtained by multiple regression. This model has a low computational cost and can be used for molecular screening of SF₆ alternative gas from the point of insulation property. In addition, by studying above predictors with clear physical meaning, it can be helpful to analyze how to make considerable improvements in the electrical strength, which can prompt the process of molecular design of SF₆ alternative gases.