Characteristics And Modeling Of Dynamic Contact Resistance Of Pantograph-catenary Under Wave Loading

Contact resistance is a major parameter of sliding contact in pantograph catenary,the contact resistance can reflect the quality of the current in the pantograph-catenary system.The contact resistance in the pantograph-catenary system is closely related to the sliding velocity and contact electrical current,and is closely related to the contact pressure load,and the pressure load is fluctuating in the sine form during the actual train operation.The fluctuating load has important influence on the contact resistance characteristics of pantograph catenary system.Therefore,it is necessary to study the dynamic contact resistance of pantograph catenary under fluctuating load.In this paper,the influence of fluctuation amplitude,vibration frequency,sliding velocity and contact electrical current on the dynamic contact resistance characteristics is studied by using a pin and disk high speed current friction and wear experimental machine to simulate the pressure fluctuation state.The causes of the variation of the change law are analyzed with the surface morphology.The results show that,when the current-carrying is in a sliding contact and the vibration frequency is certain,the dynamic contact resistance decreases first and then increases with the increase of the amplitude of pressure fluctuation,and the dynamic contact resistance increases slowly with the increase of the pressure fluctuation frequency,and the dynamic contact resistance increases with the increase of the sliding velocity.As the contact current increases,it gradually decreases.High temperature arc and contact temperature rise are the main reasons for the change of dynamic contact resistance.The surface topography analysis shows that under the same current condition of current-carrying,the pressure fluctuation amplitude and the sliding speed are small,and the contact surface is mainly mechanical wear.When the pressure fluctuation amplitude and the sliding speed are large,it is mainly electrical wear,and the electrical wear is the main reason for the deterioration of the surface contact state and the increase of contact resistance.A mathematical model of the dynamic contact resistance of the pantograph catenary under fluctuating load is established for the influence of fluctuation amplitude,vibration frequency,sliding velocity and contact electrical current on the dynamic contact resistance.The nonlinear regression nlinfit function in Matlab program is invoked,and the parameters of the model are solved by the Gauss Newton iteration method,and verify the validity of the mathematical model.