Enhancing Control and Reliability Metrics in Subway Train Nontraction Power Supply Systems: Introducing a Novel Structural Framework

Nowadays, 2–4 inverters are installed in a metro train to feed the nontraction electrical loads (auxiliary loads). Increasingly, the reliability of these auxiliary power supply systems (APSS) is paramount, ensuring uninterrupted operation of vital subsystems such as lighting and ventilation. In this paper, a novel approach to enhance the reliability and performance of APSS is presented. Following an introduction to the conventional APSS structure, a new framework is proposed through four key steps: (1) Data input, (2) Revamped classification of auxiliary loads based on technical parameters, (3) Strategic allocation of power sources to load groups and (4) Enhancement of reliability indices. Through a detailed case study (Tehran metro’s trains), the superiority of the new APSS is demonstrated, showcasing improved control features, heightened reliability, enhanced fault tolerance and reduced implementation costs. The analysis and results reveal a significant improvement in reliability, with the new APSS exhibiting a maximum nonreliability rate of 15.4%, compared to 26.5% for the conventional system. Furthermore, the findings highlight the new APSS’s ability to maintain power supply to high-priority load groups even after multiple faults. Finally, cost analysis indicates a more economical implementation of the new APSS, with lower equipment installation and cabling costs.