SF₆-alternative gases for application in gas-insulated switchgear

The environmental problems caused by greenhouse gases have received unprecedented attention. Sulfur hexafluoride (SF₆), which is the preferred gas for use in gas-insulated switchgear (circuit breakers, disconnect switches, etc. for high-voltage electrical circuits), has a very high global warming potential, and there is a large international effort to find alternative gases. Recently, this effort has made important progress, with promising alternative gases being identified and tested. An overview, in particular the current state of the art, of the study of SF₆-alternative gases is presented in the paper. The review focuses on the application of the SF₆-alternative gases in gas-insulated switchgear, with detailed analysis of calculations and measurements of their basic physical properties, dielectric strengths, and arc-quenching capabilities. Finally, a discussion of and perspectives on current research and future research directions are presented.