Negative Sequence and Harmonic Suppression Unified Control Method for High-Speed Electric Railway

Due to the negative sequence and harmonic currents power quality problems caused by high-speed electric railway traction power supply system, this paper proposes a new type of negative sequence and harmonic unified control method, which is based on the transformer inductive filtering technology. Three-phase V/v traction transformer, combination of a inductive filtering technology and SVG system, the former is used to suppress characteristic harmonics, the latter is used to compensate negative sequence and residual harmonics. Based on ampere-turn balance principle, it fulfills the total elimination of negative and harmonic magnetic potential, so that the network side does not contain the corresponding negative sequence and harmonic currents. After analysis on the basic principle, the simulation results prove the correctness and validity of the unified control method. This method fully exploits the electromagnetic potential of traction transformer, it not only plays the role of power transmission and transformer, but also can be used for power quality control, eventually forming a transformer system that owns the function of harmonic shielding and negative sequence control.