通过CDEGS仿真软件对传统镀锌钢和新型低感石墨复合接地的杆塔接地网进行建模计算，分析了外延接地体与管道距离、土壤电阻率等因素对管道绝缘层承受电压的影响，对比这两种接地材料的散流特性。仿真结果表明:土壤电阻率增加会使管道绝缘层承受电压幅值增大；两者距离增大可减小管道绝缘层的过电压，低感石墨复合接地在高频电流作用下的散流特性优于镀锌钢。采用低感石墨复合接地进行换向引流后，管道绝缘层承受的过电压幅值明显降低。提出了采用低感石墨复合接地材料进行雷电流换向引流的过电压防护优化方案。

The grounding grid using traditional galvanized steel and new low-sensitivity graphite composite grounding tower was modeled and calculated by CDEGS simulation software. The influence of factors such as the distance between the epitaxial grounding body and the pipeline, soil resistivity and other factors on the withstand voltage of the pipeline insulation layer was analyzed, and the dissipation characteristics of the two grounding materials were compared. The simulation results showed that the increase of soil resistivity would increase the voltage amplitude of the pipeline insulation layer. The increase of the distance between the epitaxial grounding body and the pipeline could reduce the overvoltage of the pipeline insulation layer, and the dissipation characteristics of the low-inductive graphite composite grounding under the action of high-frequency current were better than those of galvanized steel. After using low-inductive graphite composite grounding for commutation and drainage, the overvoltage amplitude of the pipeline insulation layer was significantly reduced. An optimization scheme of overvoltage protection using low-sensitivity graphite composite grounding material for lightning current commutation and drainage was proposed.