不均匀沉降对变电站接地网失效影响分析  

Influence of Uneven Settlement on Substation Grounding Grid Failure

作　　者：赵欢 张国灿 陈志灵 杨志豪 施嘉炜 徐劲松 ZHAO Huan;ZHANG Guocan;CHEN Zhiling;YANG Zhihao;SHI Jiawei;XU Jinsong(State Grid Fujian Electric Power Co.,Ltd.Quanzhou Power Supply Company,Quanzhou 362000,China)

机构地区：[1]国网福建省电力有限公司泉州供电公司,福建泉州362000

出　　处：《电瓷避雷器》2024年第5期110-116,125,共8页Insulators and Surge Arresters

摘　　要：变电站地基土体不均匀沉降活动较为常见,但造成接地网破坏失效却容易忽视。本研究以某220 kV变电站地基土体不均匀沉降对接地网的破坏为案例,选择有限元分析软件ANSYS软件建立了接地网和周围土体的非线性接触有限元模型,通过仿真分析,得到该变电站接地网竖向应力水平,并讨论分析了接地材料厚度、宽度、接地网埋深、不均匀沉降差量、埋土弹性模量对接地网竖向应力的影响,分析结果表明:接地网接地扁钢的厚度、减少埋深以及选择硬质土壤回填有利于降低不均沉降时接地网的最大范式等效应力。同时对该变电站土体不均匀沉降时接地网的电阻值、土壤电阻率、最大不均匀沉降量和应力进行检测和监测,发现变电站地基土体不均匀沉降活动会导致接地网裂解从而导致其接地电阻值升高研究结果为变电站土体不均匀沉降时接地网的稳定性分析和地灾的预防处理提供一定的参考。The uneven settlement of substation foundation soil is common,but the failure of the grounding grid caused by uneven settlement is easy to be ignored.Taking this kind of grounding grid failure in a 220 kV substation in the south as an example,the nonlinear contact finite element model of the grounding grid and the surrounding soil mass is established by using the finite element analysis software ANSYS.Through simulation analysis,the vertical stress level of the grounding grid of the substation is obtained,and the thickness and width of the grounding material,the buried depth of the grounding grid,the differential settlement,as well as the influence of elastic modulus of buried soil on the vertical stress of grounding grid are analyzed.The analysis results show that the thickness of grounding flat steel of grounding grid,reduction of buried depth and selection of hard soil backfill are conducive to reducing the maximum normal equivalent stress of grounding grid under uneven settlement.At the same time,the resistance value,soil resistivity and maximum differential settlement of the grounding grid during the uneven settlement of the substation soil are detected and monitored.It is found that the uneven settlement of the substation foundation soil will lead to the cracking of the grounding grid,resulting in the increase of its grounding resistance value.The research results provide some reference for the stability analysis of the grounding grid during the uneven settlement of the substation soil and the prevention and treatment of ground disasters.

关 键 词：变电站 接地网 接地电阻 不均匀沉降 有限元分析 应力水平 

分 类 号：TM862[电气工程—高电压与绝缘技术] TM63