Virtual Screening of New High Voltage Insulating Gases as Potential Candidates for SF6 Replacement

Abstract

A virtual screening protocol was developed to screen a massive ZINC database for potential candidates for sulfur hexafluoride (SF₆) replacement as insulating gases via estimation of boiling points, dielectric strengths (DS), filtering of some other relevant properties and then Global Warming Potential (GWP) index. Firstly, we calculated the boiling points of about 1200 million compounds, which is a subset of ZINC database with the molecular weights less than 250. 1329 compounds with their calculated boiling points below 70 °C were obtained. Next, we calculated the DS of the compounds using quantum mechanical methods and 1248 compounds with their DS values above 0.8 remained. Further filtering was applied to exclude those compounds with formal charges, polar hydrogens, metal elements, and elements such as chloride, bromine, boron, silicon and tin. At last, 41 compounds resulted from the virtual screening as potential candidates for SF₆ replacement. Among these compounds, 14 were reported in literature as insulating gases with their experimental DS values between 0.8 and 2.4. The rest had the potential to be novel insulating gases. After establishing the validity of our virtual screening protocol, we further calculated the GWP values of the screened compounds and recommended potential SF₆ replacements with high DS, low boiling points and low GWP values. In summary, a virtual screening protocol was developed in this study. It is able to enrich existing insulating gases and is likely to be useful to find novel SF₆ replacement candidates.