新型环保气体在35 kV断路器中灭弧性能的仿真与实验研究

Simulation and Experimental Study on Arc Extinction Performance of New Eco-friendly Gas in 35 kV Circuit Breaker

高压电力设备中常用的灭弧气体是SF_(6),其具有良好的灭弧性能和绝缘强度。但是,SF_(6)是一种强温室效应的气体,在将来将被逐渐禁用。因此,研究以氟化腈C_(4)F_(7)N气体为代表的新型环保气体作为SF_(6)的替代气体并分析其灭弧性能,成为了近年的热点问题。电流开断是一种复杂的多物理场耦合过程,研究气体电弧的发展规律对提升断路器的开断能力意义重大。文中主要针对SF_(6)、C_(4)F_(7)N/CO_(2)不同气体介质的燃弧过程进行了仿真,得到C_(4)F_(7)N混合气体的温度分布和气压分布与SF_(6)的差异。通过35 kV断路器开断实验,可以解释断路器开断过程中的相关物理现象,并研究C_(4)F_(7)N/CO_(2)的具体灭弧性能,以判断其对SF_(6)的实际可替代性。最终结果显示,5%C_(4)F_(7)N+6%O_(2)+89%CO_(2)混合气体在单次分闸以及重合闸工况下都可以成功开断25 k A的短路电流。

SF_(6)is a common arc extinguishing gas in high voltage electrical equipment due to its perfect arc extin-guishing performance and insulation strength.However,SF_(6)is a kind of gas with strong greenhouse effect and willbe phased out gradually in the future.Therefore,the study on C_(4)F_(7)N,representing new environmental gas as an al-ternative gas to SF_(6),and analysis of its arc interruption performance has become the hot topic in recent years.Cur-rent interruption is a kind of complicated multiple physical coupling process.And the the study of the law of gas arcis of great significance for improving the current interruption capacity of circuit breaker.In this paper,the arcingprocess of such different gas medium as SF_(6)and C_(4)F_(7)N/CO_(2)is simulated and the difference of temperature and pres-sure distribution between C_(4)F_(7)N gas mixture and SF_(6)is obtained.The related physical phenomena in the interrup-tion process of the circuit breaker can be explained through interruption experiment of 35 kV circuit breaker.Thespecific arc interruption performance of C_(4)F_(7)N/CO_(2)is studied to judge its actual substitution for SF_(6).It is shown bythe final result that 5%C_(4)F_(7)N+6%O_(2)+89%CO_(2)gas mixture can successfully interrupt short circuit current at 25 k A inboth single interruption and re-closing interruption conditions.