Study on return current distribution mechanism and abnormal return mitigation in heavy haul railway traction systems considering train operation

Le résumé fourni par la source

As a critical component of the traction power supply system, the operational status of the traction return system has a direct impact on the safety and efficiency of railway transportation. With the increasing service life of existing traction power supply systems, the issue of poor return flow at traction substations has become increasingly prominent, leading to frequent safety incidents that cannot be ignored and require urgent resolution. To address this, this paper develops a dynamic train load model that accounts for variations in train traction power, speed fluctuations, and position changes based on actual train operations. By integrating the impedance of the traction network, impedance of various return paths, leakage impedance, and cross-connection lines, an equivalent model of the traction-return system is established. Power flow analysis is then employed to reveal how operational parameters influence return current distribution patterns. Building on this foundation, a comprehensive mitigation scheme for abnormal return current was proposed, incorporating the reconstruction of the substation grounding grid, optimization of N-return conductors, and the installation of a continuous earth return conductor. The scheme was validated through on-site engineering tests. Results demonstrate that the proposed model can accurately and effectively reflect real operating conditions, clearly revealing the impact of system parameter variations on the distribution of traction return current. Furthermore, the proposed optimization scheme significantly improves the distribution among return paths, effectively enhances the safety and stability of the traction power supply system. The research findings provide theoretical support and engineering reference for the design optimization, operation, and maintenance management of similar electrified railway systems.

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