Research On Sliding Electrical Contact Of Pantograph-catenary Based On Fractal Dimension Under Fluctuating Load

The pantograph-catenary system of high-speed electrified railways is the power source of electric locomotives.Only by ensuring good Current Collection can the railway be operated reliably and safely.The pantograph-catenary current receiving system is a typical sliding electrical contact system.This sliding electrical contact system is a complex current carrying friction system.The intervention of the electrical factors makes the friction and wear more complicated.The research on the sliding electrical contact of the pantograph-catenary is actually the study of the current conduction and friction and wear between the pantograph and the catenary.The fluctuation of the contact pressure load caused by flexible contact between pantograph and catenary also makes the sliding electrical contact of pantograph-catenary more complicated.In this paper,a self-made tester of high-speed current-carrying friction and wear is used to study the sliding electrical contact under the fluctuating load.The influence of the contact pressure fluctuation amplitude,frequency,sliding velocity and initial current on the current conduction and friction and wear of sliding electrical contact of pantograph-catenary is analyzed.The current conduction mainly studies the current stability,and the friction and wear mainly studies the wear rate of the pantograph slide plate.This two can respectively characterize the stability and reliability of pantograph-catenary system.The fractal theory is used to analyze the friction force signals and the current signals obtained from the experiment.And the fractal dimension of the two signals is calculated by the structure function method.It can be concluded that the fractal dimension of current will increase with the increase of sliding velocity and amplitude of load pressure fluctuation,decrease with the increase of initial current,and increase slowly with the increase of frequency of pressure fluctuation.The fractal dimension of friction force will increases with the increase of sliding velocity and amplitude,frequency of the load pressure fluctuation,and decrease first and then increase with the increase of initial current.Comparing the experimental results of current-carrying friction and wear of pantograph-catenary,it is found that the current stability is related to the fractal dimension of current,and change rules are similar;the wear rate is related to both the fractal dimension of current and the fractal dimension of friction force;and the mechanism analysis of the sliding electrical contact and wear process of pantograph-catenary with fractal dimension shows that the electrical wear changes faster than the mechanical wear.