Abstract: The flexible traction power supply system (FTPSS) based on power flow controllers can solve the problems of phase separation and power quality inherent in traditional industrial-frequency single-phase AC traction power supply systems, while providing interfaces for the integration of flexible resources such as photovoltaics (PV) and hybrid energy storage systems (HESS). The energy storage system can participate in system energy management, improving regenerative braking energy utilization and overall system efficiency. However, its power and capacity configuration is constrained by system economic performance. Meanwhile, the uncertainties in PV output and traction load pose challenges to energy storage configuration and operational scheduling. To address these issues, this paper proposes a bi?level collaborative optimization model for energy storage capacity configuration and operational scheduling in an FTPSS integrated with PV and HESS. The outer layer minimizes the total system cost and employs the grey wolf optimizer (GWO) to optimize the power and capacity configuration of the HESS. The inner layer focuses on the daily operational process and establishes a mixed?integer linear programming (MILP) model aiming at minimizing the daily operational cost. Simulation results demonstrate that the proposed method effectively improves system economic performance, confirming the application potential of the joint integration of PV and HESS in the FTPSS.