The Performance of Insulation and Arc Interruption of the Environmentally Friendly Gas CF3I

Abstract

Many researches of trifluoroiodomethane (CF3I) have shown that CF3I has many excellent properties that make it one of the possible alternatives of SF6. This paper reveals the effect laws of CF3I gas content, gap distance, gas pressure, polarity, and electric field nonuniform coefficient on the insulation performance of CF3I gas mixtures. In general, CF3I-N2 gas mixtures present a superior dielectric strength than CF3I-CO2 under different electric field sets. The experimental results indicate that 20 and 30% content CF3I-N2 gas mixtures can achieve nearly 50 and 55% insulation strength of pure SF6. In addition, to evaluate the arc interruption performance of environmentally friendly gas CF3I, we set up a CF3I transient nozzle arc model to study its thermodynamic and transport property. The analysis shows that CF3I gas has a good arc interruption capability, which mainly functions thermodynamic and transport properties approach that of SF6, and some are even better than SF6. The decomposition process is also aggravated by impurities including metal and water. The main by-products are greenhouse gases with GWP below that of SF6 and are lowly toxic and incombustible.