Integration of PV and Battery Storage for Catenary Voltage Regulation and Stray Current Mitigation in MVDC Railways

Innovative advancement in power electronics is reshaping the conventional high-voltage transmission systems and has also opened a new paradigm for researchers to consider its benefits in the railway electrification system (RES). In this regard, the medium-voltage direct current RES (MVDC-RES) is a key area of interest nowadays. In this paper, a secondary energy source (SES) consisting of renewable energies (REs) and energy storage systems (ESSs) is proposed to solve the issues of catenary voltage regulation, rail potential, and stray current in the MVDC-RES. Some of the major integration topologies of the SES are analyzed for MVDC-RES and the most effective one is proposed and implemented. The voltage at the point of connection (PoC) of the SES is used as a reference for controlling different operation modes of REs and ESSs. Moreover, feedforward control is used at the ESS converter to attain the quick response from the batteries for the desired operation. The proposed scheme improves the catenary voltage, and reduces the rail potential and stray current. Besides, the scheme provides higher energy density and reduces line losses. Simulation results are provided to validate the operation modes and advantages of the proposed scheme.