A priori quantum chemical model based on the electrostatic potential surfaces has been developed to predict the arc interruption capability of the dielectric gases straightforwardly by electronic descriptors. In terms of the rate of rise of the recovery voltage, the structure–activity relationship model is viable for the virtual screening of novel arc-quenching replacement gases for SF₆, which is superior to the routine fluid magneto-hydrodynamic model.

Abstract

The use of sulfur hexafluoride (SF₆) as an electrical insulator and arc-quenching gas in high-voltage equipment raises serious environmental concerns. The search of a replacement gas for SF₆ is hindered by a priori assessment on its interruption performance. The routine fluid or mathematic magneto-hydrodynamic models for arc burning and extinguishing are too complex to be practical for virtual screening. Herein a state-of-the-art quantum chemical model to predict the interruption capability of the dielectric gases straightforwardly has been established in terms of the rate of rise of the recovery voltage (RRRV). On the basis of the molecular electrostatic potentials, five sets of descriptors, including the global statistical parameters vσ2$$ {v\sigma}^2 $$ and Π$$ \Pi $$, the site-specific parameter ΔV _s, the total positive surface area A _s ⁺, augmented with the product of polarizability and dipole moment αμ, were optimized to reveal the inherent mechanisms for interruption and thus a viable structure–activity relationship mode for RRRV has been developed with the correlation coefficient 0.975. Theoretical RRRV relative to SF₆ = 100 for all the known dielectric gases are in good agreement with the experimental data by a mean absolute deviation of 3.6. Accordingly, the perfluorinated cycloalkenes and alkynes, in particular, 1,3,3,3-tetrafluoropropyne, are found to be the promising candidates as the replacement dielectric gases for SF₆.