Railway Virtual Power Plant: Synergistic Integration of Grid-Friendly Traction Power System and Markets into a Sustainable Development Path for Green Railways

The relatively poor power quality and low capacity utilization in the existing railway traction power supply systems (TPSSs) are the pain points for the power system and railway sectors. To address this issue, this article proposes a railway virtual power plant (VPP) based on a multi-phase flexibly interconnected traction power supply system (FITPSS) integrated with multiple photovoltaics (PVs) and energy storage systems (ESSs). First, the concept of railway VPP is introduced. Then, carbon emission reduction (CER), peak load shifting (PLS), and frequency modulation (FM) regulation modes tailored for this railway VPP are proposed, in order to effectively achieve the multifunctional demand response of an AC electrified railway to the electricity and carbon markets. To adapt to the real-time dispatching requirements of the railway VPP, a rolling scheduling approach is designed, incorporating a composite prediction error in the system and an adaptive sliding window. To achieve real-time determination of each reference power for controllable devices, the railway VPP scheduling models are developed for the optimal power flow control of the FITPSS. Finally, the effectiveness and feasibility of the proposed method are verified based on data from an actual electrified railway. A comparative assessment highlights the technical-economic advantages of the proposed strategy over literature methods.