Research On Harmonic Resonance Analysis And Suppression Technology Of AT Traction Network

With the wide application of AC-DC-AC locomotives in electrified railways,the problem of high frequency harmonic resonance on traction networks has become increasingly prominent.When the locomotive generates a large number of harmonics that coincide with the resonance frequency of the system,it will causing harmonic resonance on the traction network,causing over-voltage,over-current,equipment burning,and locomotive stop operation,which will endanger the safe and stable operation of the system.Therefore,it is necessary to analyze the harmonic resonance characteristics of the traction network,study the harmonic resonance law under different conditions,and adopt a reasonable and effective scheme to control.This paper takes an AT traction network resonant accident line as an example.Based on MATLAB/SIMULINK software,a traction power supply system model was built.The Norton equivalent model of locomotive is obtained by pulling the measured data of harmonic current on the network,and “locomotive-traction network” system is established.And then analyzing the basic theory of harmonic transmission characteristics,harmonic amplification characteristics and resonance principle,further studying the effects of harmonic resonance on different short-circuit capacity,locomotive position,power arm length,and power supply mode.According to the serious damage caused by harmonic resonance to the system,this paper proposes control ideas for different objects.Several common harmonic resonance control devices compare the Resistance-frequency characteristics,power characteristics,filtering effects,economic performance,etc,and select a second-order high-pass filter device.Then Parameter design,installation method,configuration selection,and transient analysis are performed to determine the control scheme and prove that the scheme is reasonable and effective.Considering the special conditions that may be dealt with after the second-order filter is put into system,Proving and evaluating of the scheme’s effects under different conditions.such as small short-circuit capacity,multiple locomotive operation,Up or down railway splitting,partition splitting,and cross-regional power supply.The results show that the scheme can effectively filter out the higher harmonics,and the effect is good,which provides a reference for the practical application of harmonic resonance control.