Study On Contact Resistance Characteristics Of Pantograph And Catenary System Of Trains And Its Influencing Mechanism

Trains can get energy from the only way of pantograph and catenary system.Its good service performances are the important condition for the current collection quality and safe operation of trains.With an increase of operation lines and the speed of trains,the vibration of pantograph and catenary system aggravates,which leads to the frequent occurrence of pantograph arcing.Meanwhile the electric contact status of pantograph and catenary system become more complex,which leads to the abnormal wear of pantograph strips even the fracture of pantograph strips,and the train will break down.The service performances of pantograph and catenary system contain mechanical properties and electrical contact properties,which need a much higher level due to the change of operation conditions.At present,the evolution law of electrical contact performances of pantograph and catenary system was not clear.Therefore the further study of electrical contact properties of pantograph and catenary system need to be carried out,which can provide a theoretical basis for improving electrical contact performances of pantograph and catenary system.In this paper,the research object is the electrical contact property of pantograph and catenary system.The experimental studies of that have been carried out through the dynamic contact resistance,temperature rise,the worn surface morphology of pantograph strips and the arc ablation resistance.The main research conclusions are as follows:According to characteristics of electric contact of pantograph and catenary system,experimental studies of dynamic contact resistance had been carried out through the simulation test device.Firstly changes of dynamic contact resistance and the wear loss of pantograph strips were verified under different electric current,contact pressure,and sliding speed.Then the influence mechanism of dynamic contact resistance on the the wear loss of pantograph strips was interpreted.Meanwhile the approximate linear relation of those had been found.Finally the value range of contact pressure of pantograph and catenary system was put forward from the perspective of electrical damage.Firstly the temperature distributions in the strip and its variations were recorded by a thermal infrared imager.Then the influence of electric current,zigzag movement and strip materials on temperature distributions of pantograph and catenary system was analyzed in accordance with the theory of heat transfer.Meanwhile the change of temperature distributions under different conditions was verified,and the influence of friction heat,joule heat and arc heat on temperature rise of pantograph and catenary system was analyzed.The dominant role of electric effect in temperature rise was demonstrated.Finally the temperature distribution of pantograph strips suggestted a good symmetry.Based on the simulation test device,the study of friction and wear properties of pantograph and catenary system was carried out.The influence of different conditions on the worn surface morphology of pantograph strips was studied,and then typical areas of that were divided.Meanwhile the formation of the worn surface morphology was investigated with or without electric current.The influence mechanism of the worn surface morphology under the current was investigated.Moreover the radial crack was formed in arc ablation areas.In this work,the arc erosion experiment using carbon strips and a pure copper electrode were carried out.The change of the arc ablation loss of pantograph strips was verified,and the formation of macroscopic and microscopic appearances in the arc ablation crater was analyzed.Finally the damage mechanism of pantograph strips under the action of mechanical friction,current-carrying friction and arc ablation had been put forward.