Study Of Matching Locomotive With Traction Network For High-speed Railway

AC drive electric locomotive for high-speed electrified railway adopts Pulse Width Modulation technology, it is very different from traditional AC-DC electric locomotive in harmonic characteristics, it eliminates primary low order harmonics, and reduces total harmonic distortion, but its harmonic frequency is more widely distributed, the possibility of harmonic resonance between locomotive and traction power network will greatly increase.Combined model of AT traction power network or NF traction power network and locomotive used in high-speed railways is found, law of harmonic resonance between locomotive and traction network is studied.Based on theory how four quadrant PWM converter works and its harmonic voltage expressions, equivalent circuit model in ac side is set up, harmonic current expressions of locomotive is derived to analyze how voltage and power have influence on current spectrum.Network structure of AT traction power network and NF traction power network for high-speed railways is analyzed, traction power network is naturally divided up to obtain chain network including parallel multi-conductor transmission lines and vertical element according to transverse connection of traction power network and locomotive's position. The theory about multi-conductor transmission lines is used to build model of traction power network, classical Carson theory is used to calculate series impedance matrix and shunt admittance matrix, transmission lines are equivalently complicated according to traction network vertical connection, Phase-Model theory is used to build equivalentπharmonic model of traction power network.Based on matlab/simulink software combined model of locomotive and traction power network for high-speed railway is found to study impedance frequency characteristics and distribution characteristics of AT-CRH2 system,AT-CRH5 system,NF-CRH2 system and NF-CRH5 system, and analyze how parameter of traction power network have influence on law of harmonic resonance between locomotive and traction power network.