改写：A mathematical model was established under direct supply mode and the influence of grounding grid resistance on the distribution of ground return current in traction substations was discussed The d

Under the direct supply mode, a mathematical model was created to examine the impact of grounding grid resistance on the distribution of ground return current within traction substations. The analysis and study of the distribution pattern of harmonic current in the ground return current of traction substations were conducted. Additionally, the issue of electrical corrosion of steel bars in the grounding grid of traction substations was investigated, and potential solutions were suggested.