The Performance Analysis of the "Train-Rail" Grounding System for High-Speed Trains Considering Circumflux and Train Body Voltage

The 'train-rail' integrated grounding system for high-speed trains plays the critical role in providing the unique path for power feedback, which mainly consists of two parts - the on-board dynamic grounding sub-system and the fixed terrestrial grounding sub-system. The on-board dynamic grounding sub-system can be classified into two types of grounding modes - working grounding provides the discharging path for transferring the traction power; while the protective grounding maintains reference ground potential for the train body - both of which share the rail as the common path for discharging current. Thus, the traction current discharged from the working grounding wheel sets flows through the neighboring protective grounding wheel sets back to the train body, forming as the 'train-rail' current reflux. The 'train-rail' current reflux may result in the appearance of a 'train body' (TB) current, which may rise the potential of the train body. The TB current and voltage may cause electromagnetic interference to the on-board equipment, electrochemical corrosion on grounding wheel bearing or even on-board partial temperature surging. In this paper, a 'train-rail' coupling integrated grounding model is launched to evaluate both the TB current and voltage. Based on this model, different grounding distribution schemes have been tried and compared, considering the impact brought from TB current and voltage. The external grounding resistors are installed in series at the protective grounding wheel sets implemented, with the aim of restricting the TB current and voltage. Ultimately, the best-performed grounding scheme of installing external resistors is found out.