Lightning Impulse Discharge Characteristics of CF₃SO₂F Ternary Gas Mixtures

Experimental studies on the lightning impulse insulation characteristics of CF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>SO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>F-based ternary gas mixtures as potential substitutes for SF6 reveal that the 50% breakdown voltage exhibits a linear increase with rising pressure within the 0.1-0.5 MPa range. Specifically, the gas mixture comprising 16% CF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>SO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>F + 7% C<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</inf>F<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</inf>N + 77% N<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> or CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> demonstrates remarkable performance, achieving over 95% of SF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</inf>'s 50% lightning impulse breakdown voltage at 0.5 MPa. Notably, the nitrogen-based mixture shows superior insulation strength compared to that of CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>-based mixture. Theoretical analysis indicates a favorable liquefaction temperature of -30°C for this ternary mixture, coupled with a global warming potential (GWP) below 5% of SF6's value. These findings suggest that the CF<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf>SO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>F-based ternary gas mixture presents a promising SF6 alternative, offering comparable insulation performance at equivalent pressure while enabling more compact equipment design and significantly reduced environmental impact.