基于有限元分析的石墨基柔性接地体冲击接地特性研究

Impact Grounding Characteristics of Flexible Graphite Grounding Body Based on Finite Element Method

针对目前电力系统中存在的接地体严重腐蚀问题,新型柔性石墨接地材料得到了一定程度的应用,然而对于该材料接地特性的研究依然不够完善,选用接地体时沿用金属接地体的设计思路,因此在实际使用过程中仍然存在一定问题。基于此,笔者在考虑土壤非线性火花效应的前提下,建立了接地体有限元分析模型,通过试验验证仿真模型准确性后,比较研究了石墨基柔性接地体与钢接地体之间冲击接地特性差异,并以此为依据对两种接地体的有效长度进行了相应分析,同时还确定了两种接地体在不同频率电流下的趋肤深度。研究结果表明:接地体的冲击接地电阻主要与接地体尺寸相关,材料自身电气特性影响相对较小,同时石墨基柔性接地体有效长度相比钢接地体较长,且其趋肤效应较弱,因此接地材料的整体利用率较高。

In view of the serious corrosion problem of the grounding body in the current power system, the new flexible graphite grounding material has been applied to a certain extent, but the research on the grounding characteristics of the material is still not perfect. The design idea of the metal grounding body is used when the flexible graphite grounding body is selected, so there are still some certain problems in practical use. Based on this, the author used the finite element method to analyze the grounding body considering soil nonlinear spark effects. After confirming the correctness of the simulation model through experiments, the difference in impact grounding characteristics between the graphite-based flexible grounding body and the steel grounding body was compared and analyzed. The effective length of the two grounding bodies was analyzed, and the skin depths of the two grounding bodies under different frequency currents are also determined. The research results show that the impact ground resistance of the grounding body is mainly related to the size of the grounding body, but not the electrical characteristics of the material itself. At the same time, the effective length of the graphite-based flexible grounding body is longer than that of the steel grounding body, and its skin effect is weaker. Therefore, the utilization rate of the grounding material is high.