R-134a and C02 Mixture as a Sustainable Alternative to SF6 and CO2

Abstract

SF6, Novec 4710 is used as a dielectric in the gas insulated equipment due to its sufficiently high dielectric strength properties. However, these are hazardous for the environment due to their high global warming potential and long atmospheric lifetime. Therefore, new gases are required to be introduced as the alternatives to SF6 and Novec 4710. R-134a has excellent dielectric characteristics, but it cannot be used alone due to its high boiling point. To compensate for that, C02was mixed as a gas carrier to achieve a high boiling point like that of SF6. Sphere-sphere electrodes were used with the gap measurement of 6mm. The comparison of different ratios shows that for HVAC, 80% of R-134a and 20% of C02mixture constitutes a good proportion for high voltage applications. For HVDC, 90% of R-134a and 10% C02shows better result. Also, the synergistic effect is evidently better for 70/30 ratio of R-134a/C02, and its self-recoverability characteristic is effectively improved.