ARC EXTINGUISHING PERFORMANCE OF ENVIRONMENTAL-FRIENDLY GAS MIXTURE C₄F₇N-CO₂ IN A DISCONNECT SWITCH

Sulfur hexafluoride (SF6) is known for its excellent arc extinguishing performance and insulation performance. However, SF6 is a strong greenhouse gas, and its liquefaction temperature is relatively high. Therefore, looking for an environment-friendly, high-performance gas to replace SF6 is an urgent problem to be solved in the field of high-voltage power switches. The current research results show that C4F7N and its mixed gas have great potential in replacing SF6 gas. According to other papers, the gas mixture of C4F7N and CO2 can meet the ambient temperature requirements of the current power equipment application and has good insulation performance and low global warming potential. Although the mixed gas of C4F7N and CO2 has good arc extinguishing performance as a whole, its arc extinguishing mechanism in disconnect switches is still unclear. Therefore, in order to verify whether the gas mixture of C4F7N and CO2 meets the breaking performance of the isolating switch, this article focuses on the simulation study of the breaking process of the gas mixture of C4F7N and CO2, and analyses the breaking process of different types of small currents. In addition, this paper also conducts tests on disconnecting switches under different working conditions to break small currents, and it is verified through the tests that this mixed gas can meet all the requirements for disconnecting switches to break various small currents.