A Planning and Control-Integrated Design Approach for Railway Power Flow Controller With Hybrid Energy Storage System

Integrating energy storage systems (ESSs) into the railway power flow controller (RPFC) offers a promising path to enhance the interaction capability and connection compatibility between the railway power systems (RPSs) and the utility. Despite its technical advantages, full consideration must be given to the media-type & configuration of ESS, the rating of RPFC, and the control framework that can compatibly integrate the control & planning for cost-efficiency improvement. For this problem, a novel concept that takes the real-time control and off-line configuration approach in a unified framework is proposed for hybrid ESS-integrated RPFC (HESS-RPFC) in this paper, in which the comprehensive techno-economic performances of the whole system are taken into account. First, a unified analytical power regulation framework is established for HESS-RPFC, in which the functions of energy management (EM) and power quality control are seamlessly integrated. To realize EM, improve RPS’s grid-connection compatibility, and reduce the rating of RPFC, a double-layer power regulation strategy of HESS-RPFC is developed on the proposed framework. Subsequently, a lifetime net benefit-oriented optimization model is formulated and solved, through which, the optimal rating configuration of the whole system and HESS’s mode-triggering thresholds can be obtained. Finally, a comprehensive performance evaluation based on real-measured data is conducted, revealing that HESS-RPFC with the proposed method provides superior economic benefits over single-media ESS schemes, ensures satisfactory grid-connection compatibility for the RPS, and reduces the RPFC’s rating by nearly 46%. Additionally, the real-time execution feasibility of the proposal is demonstrated by hardware-in-the-loop tests.