To optimize gas formulations for reducing the gas pressure in eco-friendly gas-insulated equipment

this study investigates the power frequency breakdown characteristics of CF3SO2F ternary gas mixtures. Experiments are conducted to obtain the breakdown characteristics of CF3SO2F ternary mixtures in slightly non-uniform electric fields under pressures ranging from 0.1 to 0.5 MPa. The effects of buffer gas type

pressure

mixing ratio

and low temperature on insulation strength are analyzed. Results show that under identical mixing ratios and pressures

CF3SO2F mixtures with N2 exhibit higher breakdown voltages than those with CO2. Breakdown voltages demonstrate linear growth with increasing pressure from 0.1 to 0.5 MPa. The insulation strength remains stable when temperature decreases from 20℃ to -20℃ but significantly declines below -20℃. The optimized 20%CF3SO2F/ 10%C4F7N/70%N2 ternary mixture demonstrates an insulation strength 15% higher than that of SF6 at 0.5 MPa while its liquefaction temperature remains below 20℃. This research provides valuable references for developing alternative gases of eco-friendly gas-insulated equipment.