Modelling and Simulation of New Traction Power Supply System in Electrified Railway

In conventional single-phase 25kV AC traction power supply system, there are some outstanding power quality problems including three-phase voltage unbalance and large reactive power. Moreover, the neutral section insulators at exits of substations affect the safety and efficiency of the electric trains, especially in high speed railway and heavy haul railway. In this paper, a new traction power supply system adopting single-phase traction transformer and active power flow controller (PFC) is proposed. In the new system, the power quality problems caused by single-phase traction load are solved in grid side and the continuous power can be provided to electric trains without neutral sections in traction side. The mathematic model of the new system is built and the compensation currents of PFC are calculated. Moreover, the optimized topology and control method of PFC are studied. Based on MATLAB software platform, the simulation results verify the validity of the proposed system.