季节性冻土环境下输电杆塔地网接地特性研究

Study on the Grounding Characteristics of Transmission Tower Grounding Grid Under the Seasonal Frozen Soil Environment

季节性冻土的融冻循环过程会导致土壤电阻率和冻土层分界面随季节变化,冬季输电线路杆塔地网接地电阻可能上升,甚至超过标准限定值,影响线路的安全稳定运行.为了研究季节性冻土因素对杆塔地网接地电阻的影响,仿真研究了冻土层结构及冻土层厚度对其接地电阻的影响,并采用柔性石墨和圆钢接地材料同沟敷设的方案对实际输电线路杆塔地网进行了改造,对比分析了接地电阻的差异.研究结果表明:在不同冻土层结构和冻土层厚度情况下,柔性石墨地网相比于圆钢地网,其接地电阻最大降阻率分别达到了18.76%和23.65%.研究成果可为季节性冻土环境下输电线路杆塔接地降阻提供参考.

The cycle process of seasonal frozen soil melting and refreezing will cause the soil resistivity and frozen soil interface to change with the season,which will result in the rise of grounding resistance even more than standard limit value in winter,and affect the safe and stable operation of the transmission lines.In order to explore the impact of seasonal permafrost factors on grounding resistance of grounding grids.Simulation calculations is adopted to study the influence of different soil layered structure and thickness of frozen soil layer on the grounding resistance.And using a design scheme of laying two different grounding bodies in one ditch to remold the actual transmission tower grounding grids.The results show that in the two cases described above,the maximum resistance-reducing rate of the flexible graphite grounding grids compared with the steel ones reaches 18.76%and 23.65%respectively.The research results can provide a reference for reducing the grounding resistance of transmission tower in the seasonal frozen soil environment.