Improved control strategy of zero-resistance converter system for rail potential and stray current mitigation

Abstract

ABSTRACT In urban rail transit, the running rails are generally employed as the traction current return path, which inevitably causes rail potential and stray current issues. As one of the solutions, zero-resistance converter system (ZRCS), consisting of negative resistance converters and switch units, establishes zero-resistance loops to shorten the return loop of traction current in running rails, so as to mitigate rail potential and stray current. Considering the defects of accumulated detection errors by multiple voltage sensors in traditional control strategy (TCS), an improved control strategy (ICS) taking rail potential at specific points as control objects is proposed. Furthermore, based on mathematical model of ZRCS, the rail potential and stray current distributions under different control strategies are discussed. Compared with TCS, the ICS enhances ZRCS rail potential and stray current mitigation performance. Finally, the feasibility and effectiveness of the ICS are validated through experimental verification.