A Voltage Level Design Method for Direct Current Autotransformer Based Medium Voltage Direct Current Traction Power Supply System

Due to the improved power supply capability, the medium voltage direct current (MVDC) traction power supply system (TPSS) based on the direct current autotransformer (DCAT) has become a promising solution for future electrified railways. However, as the heart of DCAT-based MVDC TPSS, the voltage level still lacks a systematic design method. To address this issue, this paper presents a comprehensive voltage level design method. The key metrics including voltage fluctuation, stray current, rail potential, traction network temperature, and economy are all considered and modeled. Then, the design process of voltage level is provided with a specific case study. A simulation model is built and the results prove the effectiveness of the proposed voltage level design method.