Supercritical Fluids as Alternative Insulation and Arc-Quenching Medium

This paper reviews the historical progression of arc-quenching media and examines the unique properties of supercritical carbon dioxide (scCO2), including its transport characteristics, electrical breakdown resilience, and structural behavior. Through analysis of ionization mechanisms, mean free path, and heat dissipation, scCO2 emerges as a viable insulating and arc-quenching medium, offering competitive performance and reduced environmental impact. Projected performance metrics for arcing time and dielectric strength show scCO2’s competitive edge. The limitations of alternative supercritical fluids and the potential benefits of scCO2 mixtures are discussed. In addition, the paper highlights the development of the first 72 kV scCO2 AC circuit breaker, marking a significant step toward sustainable high-voltage applications. This work positions scCO2 as a viable, environmentally friendly alternative to SF6, with promising implications for future power systems.