Research On Temperature Rise And Temperature Distribution Model Of Collector Shoes

Collecting boots and contact rail system are important ways to provide electric energy for trains in urban rail transit.The electrical contact performance of boot-rail system directly affects the quality of power supply and the running safety of trains.The electric contact of boot-rail system can be divided into dynamic electric contact and static electric contact.When the train stops,because the electrical equipment on the train is still running,the collector shoe and the contact rail are relatively static at this time,the current flows through the contact surface of the shoe-rail,and the temperature rises through the contact resistance.If the contact resistance is larger or the heating time is longer,it may damage the shoe-rail,and the larger contact resistance will also affect the quality of power supply.Therefore,it is necessary to study the contact resistance and temperature of shoe-rail system.In this paper,the static electrical contact performance of boot-rail system is studied by combining theoretical analysis with experimental test.Based on the theory of electric contact,the electric contact model of shoe-rail is established and the calculation formula of contact resistance of shoe-rail is deduced.According to the theory of heat conduction,the temperature model of shoe-rail is established,and the calculation formula of temperature rise and temperature distribution is deduced.The calculation formula is verified by the temperature test of the slide plate of the collector shoe,and the correctness of the electric contact model of the shoe rail and the temperature model of the slide plate is proved.The results show that the contact resistance of shoe-rail is about 7-12 milliohms.When the current is small or the contact force is large,the contact resistance is stable.When the current is large,the contact resistance fluctuates greatly due to the factors such as higher temperature and softening of the surface of the shoe-rail.The temperature rise model of the slider of collector shoe is more accurate at low current,and the steady temperature of the slider is more error at high current,but the short-term temperature rise process is still more accurate.The spherical and cylindrical temperature distribution formulas are fitted by the least square method,and the residual values are compared.It is found that the isothermal surface in the slider is more in line with the cylindrical temperature distribution.The cylindrical temperature distribution is used to calculate that when the current is 100 ampere,the temperature of the shoerail contact surface is over 200 ?.Increasing the contact force can reduce the temperature and contact resistance of the contact surface.In order to solve the problem of excessive temperature and contact resistance of shoe-rail contact surface when the train stops,static contact force of shoe-rail system can be increased and uniform force can be exerted when the train stops,so that the isothermal surface of shoe-rail contact surface is closer to the cylindrical distribution,and the heating of shoe-rail contact surface can be reduced.