Study on new traction power supply system for power quality comprehensive compensation in electrified railway

The outstanding power quality problems including three-phase voltage unbalance and large reactive power have drawn more and more attention of railway company and power system. 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. A new traction power supply system adopting Vx connection traction transformer and active power flow controller (PFC) is proposed. The mathematic model of the new system is built and the compensation currents of PFC are calculated for comprehensive compensation. Moreover, the optimized topology and control method of PFC are studied. The simulation and performance of the different operation modes verify the validity of the proposed system, which can be used in high speed and heave haul railways.