CO2气体断路器弧后击穿特性计算分析

Calculation and Analysis of Post-arc Breakdown Characteristics of CO2 Gas Circuit Breaker

六氟化硫(SF6)具有优良的绝缘与灭弧性能,广泛应用于电力设备中,但该气体是一种强温室气体,已被要求限制甚至停止使用。二氧化碳(CO2)灭弧性能优良,作为一种潜在的灭弧介质替代SF6气体具有较大应用前景。针对CO2气体在高压气体断路器中的应用,围绕弧后击穿特性这一核心问题,通过磁流体动力学电弧仿真和弧后热击穿与电击穿特性评估,分析了CO2气体电弧的弧后介质恢复特性,及其与SF6气体的差距,进而探讨了采用CO2气体作为高压气体断路器灭弧介质的可行性与关键问题。结果表明:文中断路器结构下CO2电弧热开断能力约为SF6气体的28.7%;弧后CO2气体介质恢复速度较SF6气体慢,动触头前端的区域电击穿发生概率较高;提高CO2气体充气压力可有效提高电弧热开断能力和弧后介质恢复强度;该研究可为环保型高压气体断路器的研制与优化提供参考。

Sulfur hexafluoride(SF6) has excellent insulation and arc quenching properties and is widely used in electric power equipment. However, this gas is a strong greenhouse gas, and has been required to be restricted or even stopped. Carbon dioxide(CO2) has excellent arc extinguishing performance, and it has a great application prospect instead of SF6 gas as a potential arc extinguishing medium. Consequently, we focused on the application of CO2 gas in high-voltage gas circuit breakers, and analyzed the post-arc breakdown characteristics by magnetohydrodynamic arc simulation and post-arc thermal and electrical breakdown characteristics. Moreover, we discussed the feasibility and key issues of using CO2 gas as the arc extinguishing medium of high-pressure gas circuit breaker. The results show that the arc thermal interrupting capability of CO2 under the present circuit breaker structure is about 28.7% of SF6 gas;the rise rate of recovery voltage of CO2 gas during post arc is slower than that of SF6 gas, and the probability of dielectric breakdown at the front end of moving contact is higher;Elevating gas pressure can effectively improve the arc thermal interrupting capability and recovery strength during post arc. This study can provide references for the development and optimization of environmentally friendly high-pressure gas circuit breakers.