Modeling Of High-speed Railway Traction Power Supply System And Research On Resonance Suppression Strategy

Based on the needs of high-speed,high-efficiency,heavy-load,and safety for electrified railways,a large number of AC-DC-AC EMU(Electric Multiple Units)have been invested in domestic railways.The harmonic transmission characteristics of high-speed load and normal-speed load are different.Although the high-speed load power factor is high and the harmonic distortion rate is relatively small,due to the PWM pulse width modulation technology commonly used in high-speed loads and the characteristics of the EMU itself.The distribution range of harmonics injected into the system will become larger,and the harmonic content of high frequencies will increase sharply.The higher harmonic current acts on the distributed capacitance and inductance of the traction network,which may cause the problem of higher harmonic resonance.The voltage distortion of the traction network caused by the high-order resonance will further increase the harmonic current of the high-speed load and aggravate the damage of the electrical equipment,which not only affects the safe and stable operation of the electric locomotive,but also causes unfavorable factors of the high-speed railway.Therefore,it is necessary to conduct in-depth research on the mechanism and suppression methods of higher harmonic resonance of high-speed railway.Based on the harmonic modeling of the high-speed railway,this thesis takes a high-speed railway power supply arm as the applicability study,and uses the impedance analysis method and modal analysis method to propose the high-order harmonic resonance problem of high-speed railway.A high-pass filter is used for harmonic resonance suppression.Firstly,on the basis of the existing research,the reduction and order reduction of the impedance and admittance of the traction network are deduced in detail,and the equivalent circuit model of the AT traction power supply system is established;Numerous studies the resonance characteristics of high-order harmonics under a single harmonic source,ignoring that high-frequency harmonics may also interact with adjacent EMUs to cause the increase of traction network voltage,which in turn affects the safe operation of adjacent locomotives.Therefore,the research on the high-order harmonic resonance characteristics of the high-speed railway has been further improved;thirdly,in view of the lack of research on the high-order harmonic resonance suppression characteristics of the current high-pass filter in different access positions of the traction network Supplements were made;finally,the traction power supply system was built by PLECS software,RT-Box was used to simulate the real locomotive load power,and a semi-physical simulation platform was built to verify the above theory.The results show that this thesis further studies the high-order harmonic transmission characteristics and the suppression scheme of the high-speed railway traction power supply system.It is clarified that the harmonic interaction between EMUs may further lead to the phenomenon of higher harmonic resonance,and the optimal access position scheme of the high-pass filter is proposed.It provides a theoretical basis for solving the high-order harmonic resonance problem of high-speed railway,and has a wide range of application prospects and a certain practical guiding role.