Evolution toward resilient traction power supply systems of railways with interconnected microgrids

Abstract

In recent years, the achievement of renewable and sustainable power supply in railways has become one of the foremost challenges. Thus, focused on this issue, this paper discusses the evolution toward resilient traction power supply systems (TPSSs) of railways with interconnected microgrids (IMGs), which integrates more renewable energy and guarantees stronger power supply in case of grid disturbances and failures, e.g., voltage unbalance, harmonic and violent fluctuation, power outage and extreme events in the wake of natural disasters and extreme weather. Various architectures of IMGs are proposed to be integrated in dc and ac railway electrification systems, including low voltage (LV) dc, medium voltage (MV) dc, LV ac and hybrid ac/dc IMGs. The introduction of IMG can access more renewable energy with higher power quality and sustain power supply to the locomotives in an extreme grid scenario, which facilitates the development of railway resilient TPSSs with respect to enhanced flexibility and sustainability. Then, the discussions and comparisons among different IMGs in ac and dc railway electrification systems are conducted. Finally, it is concluded that IMG-integrated resilient TPSSs provide a universal solution for high-quality power supply against grid disturbances and failures.