New cophase traction power supply system

Given the problems in the electric traction power supply system of electrified railway, such as large amount of negative sequence, harmonics and reactive power, and the losses of traction speed and power caused by the neutral section insulator between adjacent power supply areas, a new cophase traction power supply system is proposed by combining a YN, vd connected transformer with an integrated power flow controller (IPFC). The system fundamentally overcomes the three-phase unbalance issue with minimum harmonic components. The removal of the neutral section insulator meets the demand of highspeed passenger and heavy cargo services. The structure of cophase traction power supply system and the performance of the YN, vd balance transformer are discussed, and the structure of IPFC, the principle of balanced transformation and the control strategy are analyzed. Simulation results validate the feasibility of the proposed scheme.