Integrated configuration and control strategy of PV generation in railway traction power supply system

Abstract

Recently, electric railways have experienced a rapid development with an increasing power demand. Due to the flexible installation at trackside land along railways, photovoltaic (PV) generation is suggested to extend to the traction power supply system (TPSS) in railway. Firstly, this paper proposes a three-phase integrated configuration for PV generation connected to two-phase traction network and on-site consumption of solar resource alongside railways. In this configuration, another inverse V/V transformer is used to maintain a balanced three-phase low voltage (LV) ac bus from two-phase traction network. It is more convenient to access more PV generation units. Then, in order to mitigate the negative sequence currents caused by electric trains, an individual phase current (IPC) control strategy for PV converters is developed for power quality improvement. It can not only supply the locomotive with asymmetrical currents but also feed back to the grid with symmetrical currents. All the implementation and calculations are conducted in the three-phase stationary reference frame without any sequence extracting and power compensations. Finally, simulation results are presented to validate the effectiveness of the proposed IPC control strategy.