土壤冻结对变电站地表绝缘安全性能的影响  

Influence of Soil Freezing on Safety Performance of Substation Surface Insulation Layer

作　　者：罗琛 马力 苟旭丹 詹旻 杨峰 蔡刚林 曹晓斌 LUO Chen;MA Li;GOU Xudan;ZHAN Min;YANG Feng;CAI Ganglin;CAO Xiaobin(State Grid Sichuan Electric Power Corporation Economic and Technical Research Institute,Chengdu 610041,China;State Grid Shandong Electric Power Corporation Economic and Technical Research Institute,Jinan 250021,China;School of Electrical Engineering,Southwest Jiaotong University,Chengdu 6l003l,China)

机构地区：[1]国网四川省电力公司经济技术研究院,成都610041 [2]国网山东省电力公司经济技术研究院,济南250021 [3]西南交通大字电气工程学院,成都610031

出　　处：《电瓷避雷器》2019年第1期54-59,共6页Insulators and Surge Arresters

基　　金：中央高校基本科研业务费专项资金资助(编号:2682014CX022)

摘　　要：土壤冻结地网后,地表接触电压、跨步电压会急剧增加。同时由于土壤电阻率的增加,地表绝缘层的绝缘性能亦会增强。IEEE Standard 80—2000以及国家标准GB/T 50065中给出的跨步电压、接触电压安全值表达式无法反映随着土壤冻结,冻土层结构对其安全值的影响。基于戴维南定理,利用仿真软件研究了土壤冻结后对土壤内阻所造成的影响。研究发现:土壤内阻仅由地表至地网间的土壤结构所决定,因此,土壤冻结至地网处后,土壤内阻主要由绝缘层及冻土层的土壤电阻率所决定;跨步电压下土壤内阻值约是接触电压下确定土壤内阻值的四倍,其结论与脚电阻理论相同;土壤冻结后,地表绝缘层的绝缘性能会显著增强,较上述标准确定的安全值提升1. 5倍左右。因此,按照本文结论可以减少冻土地区降阻及均压极的布置,具有一定经济价值。The contact voltage and step voltage will increase sharply after the ground network is frozen. At the same time,due to the increase of soil resistivity,the performance of the insulation layer will also increase. The safety values of step voltage and contact voltage given in IEEE Standard 80—2000 and GB/T 50065 can not reflect the influence of frozen soil layer on its safety value. Based on Thevenin’s theorem,this paper studied the effect of freezing soil on soil internal resistance by the use of simulation software.The study found: The soil internal resistance is only determined by the soil structure between the earth surface and the ground network,therefore,the soil resistance is mainly determined by the soil resistivity of the insulating layer and the frozen soil layer when the soil is frozen to the ground grid;the value of soil internal resistance of step voltage is about four times of that of contact voltage,and the conclusion is the same as that of foot resistance theory;After the soil is frozen,the performance of the insulation layer will be significantly increased,which is about 1. 5 times higher than the safety value determined by the above standards,Therefore,according to the conclusions of this paper,the number of the equipment of resistance reduction and pressure equalizing in permafrost areas can be reduced,which has certain economic value.

关 键 词：冻土 跨步电压 接触电压 绝缘层 土壤内阻 

分 类 号：TM862[电气工程—高电压与绝缘技术]