基于模拟实验与有限元仿真的针刺式接地体接地特性研究

Research on Grounding Characteristics of Needleshaped Earthing Electrode Based on Simulation Experiment and Finite Element Simulation

由于接地体电感效应的存在,在土壤电阻率较大的区域,接地体的冲击接地阻抗很难通过延长接地体长度的手段来降低,因此会影响系统的安全稳定运行。在现有接地体上增加针刺,增强雷电大电流冲击下土壤的火花效应,扩大低电阻率土壤散流区域,从而显著降低冲击接地阻抗。基于模拟实验和有限元仿真,研究了针刺设置数量、长度、间距等参数对冲击接地阻抗的影响,对针刺的布置方式进行优化。研究结果表明:针刺的长度、间隔与冲击接地阻抗之间呈非单调性,存在最佳值。通过优化针刺布置方式可以有效降低冲击接地阻抗,提高线路耐雷水平。

It is difficult to reduce the impact grounding impedance of the earthing electrodes by extending their lengths in areas with large soil resistivity due to the inductance effect,which poses risk to safe and stable operation of the system.Therefore,needle-shaped earthing electrodes are equipped on the existing electrodes to enhance the spark effect of the soil under the impact of large lightning currents,expand the low-resistivity soil dispersion area,and thereby significantly reduce the impact grounding impedance.Based on simulation experiments and finite element simulation,this paper studies the influence of the number,lengths,and intervals of the needle-shaped earthing electrodes on the impact ground impedance,and optimizes the electrode layouts.The research results show that the relationship between length,interval and impact grounding impedance is non-monotonic,and there is an optimal value.By optimizing the layout of the electrode,the impact grounding impedance can be reduced,and the lightning resistance level of transmission lines can be improved.