Study On Contact Failure Of The Pantograph's Sliding Electrical Contact Under Fluctuant Loading

With the rapid development of electrified railways,the operating conditions of all kinds of locomotives are getting larger and larger,which increases the complexity of the operation conditions of the friction pair of pantograph catenary system.Therefore,in order to improve the efficiency and stability of the electrical energy transmission of the pantograph and network,it is necessary to study the contact failure of the pantograph's sliding contact.Based on the actual operating conditions of the locomotive,this paper makes use of a self designed pantograph and sliding electrical contact experiment machine,YISHION copper contact wire and metal carbon slider.From the electric contact reliability theory,the current stability coefficient can reflect the contact failure state of the contact wire and the sliding plate of the pantograph.Combined with the current evaluation system of the high speed railway,the criterion of the stability coefficient of the current carrying current can be proposed.On the basis of collecting the experimental data,taking the surface temperature and surface morphology of the slide plate,and combining the theory of sliding contact reliability,the main reasons for the failure phenomenon of the pantograph and net sliding contact in different experimental conditions are analyzed.The effects of fluctuating load amplitude,fluctuating load frequency,slip speed and current intensity on electrical conductivity of sliding electrical contacts are studied.The fuzzy inference system is constructed by the experimental data of the full factorial experiment,and the fuzzy center is trained by gradient descent algorithm.In order to ensure the global minimum value,the simulated annealing algorithm is used to train the fuzzy inference system,and the relationship model between the wave load,velocity,current and current stability coefficient is established.The training results show that the error between the predicted value of the current stability coefficient and the experimental value is very small,and the fuzzy reasoning system is effective.The model can be used to determine whether the sliding contact of the pantograph and catenary is in contact failure state.