复杂土壤结构对杆塔接地装置冲击特性影响分析

Analysis of the Influence of Massive Texture Soil Model on Impulse Characteristic of Ground Device for Pole and Tower

随着电网输送距离的增大,输电线路不可避免要跨域河流、山地等复杂地形,准确计算复杂土壤结构中杆塔接地装置的接地参数及其冲击散流特性是输电线路杆塔接地装置优化设计的基础。本文基于有限元数值计算方法,建立了考虑河流、山体的块状土壤结构模型,对接地装置散流过程土壤中电流密度和电场强度进行分析;并对河流与接地装置的距离、山体的坡度、山体顶面积对接地装置冲击接地电阻的影响进行定量的分析。结果表明:高土壤电阻率地区,接地装置与河流距离小于5 m时,河流对接地装置散流以及冲击接地电阻影响较明显;当山体顶面积为20 m×20 m时,坡度5°≤α≤75°,接地装置敷设于山顶和山侧时,接地装置冲击接地电阻值分别增加了79. 6%和32%,山体输电线路防雷设计应综合考虑山顶面积和坡度对接地装置散流和冲击接地电阻值的影响。

As the transmission distance of the power grid increases,the transmission line will inevitably have complex terrain such as rivers and mountains,accurately calculating the grounding device parameters and the impulse-dissipation characteristics of Ground Device for Pole and Tower in massive texture soil model is the basis for the optimal design of the transmission line tower grounding device.Based on the finite element numerical calculation method,massive texture soil model considering the river,the slope of mountain and mountain crown area is established,current density,electric field strength in soil are analyzed in detail.The influence of the distance between the river and the grounding device,the slope of the mountain and mountain crown area on the impulse grounding resistance on the grounding device are analyzed quantitatively.The results show that in high soil resistivity area,the grounding device and the distance of the river are less than 5 m,which should consider the influence of the river on the current flow process of grounding device and the impulse grounding resistance;When the mountain top area is 20 m×20 m,slope to change within the range of 75°to 15°degrees,the grounding device installed on the top and side of mountain impact grounding resistance were increased by 79.6%and 25%,lightning protection design of transmission line in mountain area should be integrated into the slope of the mountain and mountain top area of effect of grounding device diffuser and impulse grounding resistance.