| Pantograph-catenary relationship,especially the current collection of pantograph and catenary is the key technical problem that affects the normal operation of high-speed trains.In recent years,the running speed of high-speed train is gradually increasing,and the phenomenon of off-line arc between pantograph and catenary is more and more frequent.The off-line arc will cause the high-speed railway unable to obtain the electric energy from the catenary normally.At the same time,the high temperature produced by the off-line arc of pantograph and catenary will cause ablation on the carbon slide plate and contact wire,reduce the service life,and even affect the safety of the train in serious cases.The harm brought by pantograph-catenary arc affects the operation performance of high-speed train and hinders the technical requirements of further speed-up of high-speed train.Therefore,in order to improve the operation performance and safety of high-speed trains,the research on off-line arc of pantograph catenary has gradually become an important aspect of high-speed railway technology.In this disseirtation,simulation,experiment and theoretical analysis are used to study the characteristics of off-line arc.First of all,this disseirtation introduces the role and influence of high-speed railway AC power supply system including pantograph and catenary in high-speed train driving.The pantograph offline arc is essentially an arc discharge that occurs in air.This article discusses the basic physical process of the breakdown arc that occurs in gas and the generation mechanism and process of the pantograph offline arc.Secondly,according to the mechanism of arc formation of the pantograph,an offline arc experiment platform for the pantograph is designed and built independently.The experimental platform used the actual copper-magnesium alloy contact wire used in the Beijing-Shanghai high-speed railway,and the pantograph used the pantograph carbon slide actually used by the CRH380 A EMU.The experimental platform more completely simulates the process of the pantograph from sliding current to dynamic offline arc generation.The offline arc detection system includes voltage,current and light intensity detection.Then,this disseirtation studies the arc characteristics of the pantograph arc formed by the experimental conditions of low voltage and high current.The changes of arc spike voltage,stable arc voltage,arc resistance,and power during the steady off-line state and dynamic off-line process of the pantograph are investigated respectively,and the volt-ampere characteristics of the arc of the pantograph are analyzed.Curve fitting of arc voltage spikes was carried out,and the effect of current on arc voltage during bow-grid offline process was explored.In addition,the voltage and current waveforms of steady-state offline arc and dynamic offline arc are analyzed by FFT transform.Finally,an offline simulation experiment platform for high voltage and high current pantograph is designed under the condition of limited power in the laboratory.The experimental platform formed a sinusoidal oscillating voltage and current waveform through the method of capacitor charging and discharging.In the process of capacitor discharge,the pantograph is separated to form an offline arc of the pantograph.And the control system is designed to achieve a good cooperation between the capacitor discharge and the separation of the pantograph.The characteristics of the arc generated under this condition are analyzed. |
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