Research On Vehicle-mounted Power Quality Inspection System Of Traction Network

The matching problem of electric locomotive and traction network has always affected the safety of electrified railway system;it is the focus of current research in the field of traction power supply system.Serious matching problem of electric locomotive and traction network will directly lead to traction power supply system failure,even if not directly lead to failure,it can shorten the electrical equipments life whitch are settled in traction substation and Phase-separate-station too.As the matching problem of electric locomotive and traction network with randomness and concealment,after the failure maintenance staff often can not quickly find the cause of the malfunction.If the power quality of the traction network is monitored during locomotive driving,It will helpful to the maintenance,fault prediction and fault handling of traction power supply system equipment.At present,the sampling frequency of quality monitoring system traction settled in substation and locomotive is too low to complete the monitoring tasks of monitoring the matching problem of electric locomotive and traction network.Therefore,it is necessary to develop a power quality real-time detection system for monitoring the power quality of traction network.The key identify matching problems between the electric locomotive and traction network is to find the characteristics of different match problems.However,we can only get the network voltage and current on the locomotive,so the most important thing to complete the development of power quality monitoring system is to get enough characteristics from the measured voltage and current.This article successfully gets the harmonic characteristics of different matching problem through analys the net voltage and current mainly by Fourier transform.Traction power supply system structure is very complex,different power supply section has different traction network parameters The same matching problem between different locomtives and power supply section has different characteristics.In order to find out the common characteristics that can accurately identify each matching problem of electric locomotive and traction network,this paper mainly through the simulation and measurement to complete the matching feature extraction.Five simulation models were built in MATLAB(SIMULINK)in order to study the five kinds of matching problems.By changing the parameters of the mode in the simulation platform we can simulate different power supply arms and locomotives.In this way we can get comprehensive harmonic characteristics.What's more,Harmonics analysis of the measured data is carried out.And the different matching problems'harmonic characteristics of the network voltage and current are calculated.Finally,the characteristics of different matching problems are obtained by measured results with simulation analysis.Based on the research conclusion about the harmonic characteristics of network voltage and current,a hardware system based on DSP is developed to collect and analyze the power quality of traction network in real time.The system can complete the collection of voltage and current on the secondary side of the locomotive transformer,and analyze their harmonic characteristics in real time.The system can also record and classify the power quality abnormalities.