40.5kV低SF_6含量气体绝缘金属封闭开关柜样机研制

Prototype development of 40.5kV low-SF_6 content gas insulated metal enclosed switchgear cabinet

SF6气体是6种温室效应气体之一,气体绝缘金属封闭式开关设备(C-GIS)目前基本采用SF6气体作为绝缘介质,研制一种减少或杜绝SF6气体使用的低SF6含量气体绝缘开关设备成为当下开关领域亟待解决的问题.基于现有40.5kV SF6气体绝缘开关柜气室建立三维模型,计算其电场分布、载流温升、场强等特性并对存在问题进行仿真优化;确定SF6体积分数为30%、充气压力为0.15MPa的SF6-N2混合气体为开关柜气室绝缘介质;优化设计后气室内电场强度最大值明显降低,隔离断口、接地断口、真空灭弧室绝缘拉杆的电场强度最大值分别由7.28、7.81、8.24kV/mm降至5.05、5.03、4.21kV/mm,1.1倍额定电流时气室内温度最高值为67℃.基于上述结论研制一种40.5kV低SF6含量C-GIS样机,对样机进行工频耐压试验、雷电冲击耐压试验和温升试验,样机无闪络现象发生,温升符合国家标准要求,顺利通过型式试验测试.

Since SF6 gas is defined as one of six greenhouse gases,and most of existing cubicle-type gas-insulated switchgears （C-GIS）take SF6 gas as insulating dielectric,it has been an urgent problem in the switchgear field to develop gas-insulated switchgear with lower-SF6 content,which can reduce or eliminate the usage of SF6 gas.The 3D gas chamber model in switchgear is established based on the current 40.5 kV SF6 C-GIS;and the related electrical features are calculated,including voltage distribution,current carrying temperature-rise and electrical field intensity.And then,the structural optimization for existing problems is done.The mixed gas of 30%SF6-70%N2 under 0.15 MPa is selected as insulating dielectric for the switchgear chamber.And the simulation results indicate that electrical field intensities in the chamber decrease markedly after structural optimization,the max electrical field intensity at isolating break,grounding break and isolating drawbars of the vacuum interrupter decline from 7.28,7.81,8.24 kV/mm to 5.05,5.03,4.21 kV/mm,and the highest temperature in the chamber is 67 ℃ under 1.1 times of rating current.A 40.5 kV C-GIS prototype with lower-SF6 content is presented based on the above-mentioned researches. And the power-frequency withstand voltage test,lighting impulse voltage test and temperature-rise test are applied to the prototype.The test results show that there is no flash-over in the tests,the temperature-rise can meet the national standard demands,and the prototype past the type-tests successfully.