Dielectric characteristic of dichlorodifluoromethane (R12) gas and mixture with N2/air as an alternative to SF6 gas

In this study, dichlorodifluoromethane (R12) gas and mixtures with nitrogen (N2) and air at different pressures and mixing ratios have been investigated and showed good alternative to S F 6 gas in terms of high-voltage application. Mixed gases contain R12 gas, they offer good dielectric properties and possibility to be used in low-temperature environment. Synergistic effects and self-recoverability test have been performed. Dielectric strength under quasi-uniform field showed in the order of S F 6 > R 12 > N 2 > air in alternating current (AC), direct current (DC) and impulse was examined. Mixture R12/N2 (80/20%) could reach over 0.90–0.95 times to that of S F 6 gas at 50 lb/in2 at AC and R12/air (70/30%) gives 0.80–0.90 to S F 6 gas. R12 gas presents brilliant self-recoverability. The optimal ratio to switch S F 6 gas is R12/N2 (80/20%) and R12/air (70/30%) is based on the authors’ experimental condition and setup.