典型特高压杆塔基础接地计算与分析

Calculation and Analysis of Grounding Body of Typical Tower Foundation for UHV Power Transmission

为研究人工水平接地体对特高压杆塔基础接地电阻及散流的影响,在CDEGS软件中建立了典型特高压杆塔基础及人工水平接地体仿真计算模型,分别对不同根数水平接地体、不同水平接地体长度、不同土壤电阻率的降阻率及散流比进行仿真计算。计算结果表明:水平接地体对特高压杆塔基础接地电阻减小效果并不十分明显,特高压杆塔接地应充分利用其自然接地体作用。另对3种典型特高压杆塔基础接地体电流密度分布进行计算,计算结果表明,单桩垂直型接地体有最大电流密度。当入地电流为10 A时,非底段的最大电流密度为1.156A/m。

To research the impacts of artificial horizontal grounding body on grounding resistance and current divergence of tower foundation for UHV power transmission,based on CDEGS software a simulation model for typical tower foundation for UHV power transmission and its artificial horizontal grounding body is built,and simulation computation of resistance-reducing rate and current divergence ratio under different soil resistivity,different lengths of horizontal grounding body and horizontal grounding body with different number of electrodes is performed.Simulation results show that the effect of horizontal grounding body on grounding resistance reduction of tower foundation for UHV power transmission is not so evident,so the effect of natural grounding body should be fully utilized to the foundation grounding of towers for UHV power transmission.Current densities in foundation grounding bodies of three typical towers for UHV power transmission are calculated,and calculation results show that the current density in vertical single-pile grounding body is the maximum.When the grounding current is 10A,the maximum current density appears at the bottom segment of the grounding body and the maximum current density at non-bottom segment of the grounding body is 1.156 A/m.