Harmonic Analysis Of Traction Power Supply System Of Universal Speed Railway

In recent decades,electrified railway has been booming,traction power supply system is an important part of electrified railway,due to the particularity of traction load will lead to a large number of harmonics in the system,so that traction power supply system and local power grid in an unstable state,serious accidents will be caused.Therefore,the study of harmonic transmission characteristics of traction power supply system is helpful to improve the quality of power grid and ensurethesafety ofrailway transportation.Firstly,the mathematical model and theoretical analysis of traction transformer,traction network and electric locomotive are established.The voltage and current relationship between the primary and secondary side of the transformer with single-phase connection,V/V connection,SCOOT connection and three-phase YNd11 connection modes are analyzed,and the unbalance degree and capacity utilization rate of the four connection modes are calculated.By using carson theory,the structure of multi-conductor space line is simplified,and the impedance of the equivalent catcontact line,rail and positive feeder is calculated.The working principle of electric locomotiveisanalyzed andfourcommutationprocesses areexplained.Secondly,with PSCAD as simulation software,the traction transformer simulation model was established and the voltage and current waveform of the power supply arm were simulated by simulated load.The equivalent model of double-wire electrified traction network was established with 5km as unit length.The commutation process of locomotive rectifier under different output voltages is analyzed.The commutation output voltage,current and harmonic characteristics of locomotiveinfourcommutationprocesses areanalyzed.In addition,in the whole traction power supply system,the AT power supply method is used to analyze the harmonics in different positions of the traction network by Fourier analysis,and the magnitude of the odd harmonic component is calculated.The simulation models of different locomotive positions and numbers were established,and the harmonic current variation was analyzed,andtheharmonicvoltageandcurrentdistortionratewerecompared.Finally,the performance characteristics of the first-order,second-order and third-order high-pass filters are analyzed,and the simulation of the first-order,second-order and third-order high-pass filters is carried out.A case of harmonic resonance accident in Xinyang power supply section is analyzed,and the effectiveness of the second-order high-pass filter device on harmonic suppressionis verified Figure[72]Table[28]parameter[80]...