中文摘要：

寻找1种可杜绝或减少SF6气体使用的环保型气体绝缘开关设备（GIS）成为国内外同行关注的热点。为此,理论分析了几种SF6替代气体作为气体绝缘开关柜（C-GIS）绝缘介质的可行性,基于仿真软件进行了40.5 k V C-GIS气室3维建模和电场仿真,针对仿真结果中电场强度较为集中的部位进行了结构优化。利用COMSOL计算了额定工作条件下气室内的导体温升情况,对比了充入替代混合气体时与纯SF6气体时气室的气流场与温度场分布,验证了开关柜气室散热效果。仿真结果表明,优化后气室内最大电场强度由8.24 MV/m降至5.00 MV/m以下,充入气压为0.15 MPa的SF6（体积分数为30%）和N2（体积分数为70%）混合气体的气室内部最高温度为67℃,略高于充入纯SF6气体的气室。基于仿真结果搭建了简易气室工装并对它进行了耐压和温升测试,气室施加215/185 k V雷电冲击电压时无闪络击穿,1.1倍额定电流下气室温升符合国家标准规定,证明上述混合气体作为开关柜绝缘介质可满足电场强度和散热特性的要求。

英文摘要：

Finding environment-friendly gas for insulated switchgears （GISs） to eliminate or reduce the usage of SF6 has been a focus for related researches. We theoretically analyzed the feasibility of several alternatives to SF6gas as the insu- lating dielectric in cubicle gas-insulated switchgears （C-GISs）. Using simulation software, we performed 3-D modeling and electric-field simulation of the gas chamber in a 40.5kV C-GIS, and optimized the structure of those parts with high electric-field intensity. Temperature-rise of the conductor in the gas chamber under rated operating condition was calcu- lated using COMSOL. Through comparing temperature field and airflow field in the gas chamber filled with different gases, heat dissipation in the gas chamber was verified. The simulation results indicate that the maximum electric-field intensity in the chamber declines from 8.24 MV/m to 5.00 MV/m after the structural optimization. When the gas chamber is filled with mixed gas of SF6 （30% in volume fraction） and N2 （70% in volume fraction） of 0.15 MPa, the highest tem- perature in the chamber is 67 ℃; it is slightly higher than that of the chamber filled with pure SF6. A simple C-GIS chamber engineered device is established based on the simulation results, and it is used to conduct voltage withstanding test and temperature-rise tests. There is no fiashover or breakdown when the chamber is under 215/185 kV lighting im- pulse voltage, and the temperature-rise under 1.1 times rated current meets the national standards. It is proved that the tested mixed gas as the insulating dielectric of switchgear can satisfy the requirements of insulating strength and heat dis- sipation.