Modeling And Simulation Of Traction Network Of High-Speed Railway

In order to meet the evolving needs of our society and economy, and combined with the basic national conditions which China is an inland country with large population and has great demand for transportation, high-speed railway is developing rapidly along with the increasing efforts given by state in recent years. In the view of traction power supply system, traction transformer, traction network, EMU and integrated ground system make up a complete, closed energy flow system. As an important part of this energy flow system, traction network plays an important role in the safe operation of high-speed railway. Therefore, extracting precise electrical parameters of traction network and building a precise traction network model are of great importance.Aiming at the commonly adopted AT power supply mode targeted on high-speed railway, and combined with traction network multi-conductor transmission line characteristics and distributed parameter characteristics, chain network model is built in this article. To calculate the impedance matrix and admittance matrix of the serial subnet after being cut every1km. To solve the problem which transmission has a large number and is complex, the many transmission lines of traction network are regarded as ten wires, and the equivalent simplified methods of multi-conductor lines is derived.On the basis of calculating traction network electrical parameters based on Carson equations, some special conductor electrical parameters are extracted in different ways. In target of irregular section shape and complexity magnetization characteristics of the rail and the contact line, using electromagnetic fields finite element method to analyze, their self-impedance and capacitance to ground are precisely calculated. The calculation method of self-impedance of through ground wire is discussed. Parameters such as self-impedance, mutual-impedance and distributed capacitance of tunnel wires are calculated by all around infinite tunnel model. In addition, the coupling coefficient between the power circuit and piers is calculated by researching electrical parameters of viaducts.Traction network emulational model is built in the Simulink simulation platform, and the correctness of the built traction network mathematical model is verified by analyzing the traction network short circuit impedance characteristics and achieving the traction network short circuit impedance simulation. CRH3EMU model is built in the Simulink simulation platform too. The rectifier and inverter of EMU model differently adopt instant direct current control and indirect torque control theories. Based on the analysis on electrical parameters generated by vehicle traction transformers, pulse rectifier, intermediate circuit, PWM inverter and asynchronous traction motors, people can see that this circuit model could show CRH3EMU’s non-linear characteristics.The high-speed railway traction network and CRH3EMU linkage simulation, when EMU under the same feeding section but in different places, the traction network voltage and rail potential distribution simulation, with fixed place but in different sections, the traction network rail potential distribution simulation are realized. And through simulation analysis, traction network electrical characteristics are studied when the non-linear load is used in traction network.