Critical Breakdown Electric Field of Sulfur Dioxide at 1–10 Bar and 300–4000 K for Applications in Power Transmission and Switching Elements

The critical breakdown electric field strength (DS) of SO₂ gas is evaluated for arc quenching phase wherein high rates recovery of insulating strength (RRIS) is essentially required to stop the restrike of arc voltage for high-voltage switchgears. In this phase, the temperatures can surpass 4000 K and pressures can approach 10 Bar. These extreme conditions alter the initial synthesis of gas and subsequently affects DS of gas. The DS of gas is estimated several steps. In first step, gas composition is obtained for different temperatures and pressures using Gibbs minimum free energy criterial under localized chemical and thermodynamics equilibrium (LCE and LTE). In second step, the Townsend coefficients are calculated by solving the Boltzmann Transport Equation (BTE) through the adoption of two-term approximations. Finally, Townsend criteria are applied to determine the dielectric strength for given electric field. As per the findings, the DS of SO₂ gas at room temperature is 263 Td; however, at 4000 K and 10 bar, DS lowers to 163 Td which is better that SF₆ and CO₂ gas. Therefore, replacing the SF₆ gas with SO₂ would enhance the dielectric characteristics above 2000 K, regardless of the reduced critical dielectric strength at room temperature when compared to SF₆, Air, and CO₂. This shows that SO₂ might be a good replacement for unitary gas and as a mixture component coupled with CO₂, N₂, and other non-greenhouse gases for practical applications in high-voltage circuit breakers used as a quenching of arc and insulating medium. The experiment that was undertaken suggests that using SO₂ could improve switching equipment’s ability to withstand disruptions. The calculated results showed an impressive agreement with the observational data.