其次针对牵引回流分布分析的问题根据实际情况下带回流线的直接供电和AT供电系统中电流的路径及走向通过对直供方式下的电路模型求解得到钢轨电流和电位的分布情况推导出直供系统牵引变电所接地网回流的求解公式。由于AT供电方式下牵引网结构复杂提出采用恒定电流场原理推导出钢轨泄漏电流以及综合地线泄漏电流在大地中产生的电位公式从而推导出AT供电系统中牵引变电所接地网回流的求解公式；在此基础上运用CDEGS接地分析

Finally, to address the issue of analyzing the distribution of traction return current, based on the actual current path and direction of the direct supply and AT supply systems with return lines, the distribution of steel rail current and potential under the direct supply system was obtained through circuit modeling and solved, and the formula for calculating the grounding network return current of the traction substation under the direct supply system was derived. Due to the complexity of the traction network structure under the AT supply system, the principle of constant current field was proposed to derive the formula for calculating the steel rail leakage current and the potential generated by the comprehensive ground wire leakage current in the ground, and the formula for calculating the grounding network return current of the traction substation under the AT supply system was derived. On this basis, using the CDEGS grounding analysis software, simulation models of traction return current were established based on the Handan-Changzhi line and the Shitai-Kunshan high-speed railway line for the two supply modes, and the reliability of the simulation models was verified by comparing the grounding network return flow obtained from theoretical calculations with the simulation results. Based on the simulation model, the influence of factors such as the distance between locomotives and traction substations, soil resistivity, and the number of distributed conductors in the grounding network of the substations on the distribution of traction return current under different supply modes was analyzed.