Study On The Mechanism Of Arc Discharge For A Pantograph/Catenary System

Currently, the construction of high-speed electrified railway is a trend of railway developments all over the world. The pantograph/catenary system is one of the key components of electrical locomotives, which is used to transmit electrical power to the moving locomotives from the ground. The working performance of the pantograph/catenary system directly affects the regular operation and steady current-receiving of the electrical locomotives. In present, the service life of the pantograph/catenary system is one of urgent problems in the high-speed railways. Among many factors affecting the friction and wear behavior of the pantograph/catenary system, arc discharge is a main cause for abnormal wear of pantograph strips and contact wires. Therefore, it's essential to study the influence of arc discharge on the friction and wear behavior of the pantograph/catenary system.In the dissertation, a series of tests were carried out to study the friction and wear behavior of pantograph strips rubbing against contact wires and the characteristics of arc discharge on a high speed ring-on-block tester. The tests are studied under different normal forces, electic currents and time durations. By analyzing and comparing different friction coefficients, wear rates and topography of the contact surfaces, several conclusions can be drawn as follows:(1) The friction coefficient of the pure carbon strip/copper contact wire decreases with the increasing of normal force and electic current intensity. In the presence of electric current, the wear volume of pure carbon strip decreases with the increasing of normal force and increases with the increasing of electric current intensity. In the absence of electric current, the wear volume decreases with the increasing of normal force. The wear rate of the pure carbon strip has the same varying tendency. The wear rate of the carbon strips increases with the increasing of arc accumulated energy. And it is nearly proportional to arc accumulated energy.(2) The average time of arc discharge in one revolution of the disk decreases with the increasing of normal force. The intensity of electric current has small influence on the average time. The average power of arc discharge decreases with the increasing of normal force and increases with the increasing of electric current intensity. And it firstly decreases and then increases with the increasing of test duration. Accumulated energy of arc discharge during one revolution of disk decreases with the increasing of normal force and increases with the increasing of electric current intensity.(3) In the presence of electric current, the temperature of the worn surface in the carbon strip/copper contact wire system has little change with the increasing of normal force and firstly decreases and then becomes stability with the increasing of test time. In the absence of electric current, it decreases with the increasing of normal force and increases with the increasing of electric current intensity. The temperature of worn surfaces increases with the increasing of arc accumulated energy and is proportional to arc accumulated energy.(4) Arc discharge leads to the appearance of pittings and flow lines on the surfaces of the pure carbon strips. A large number of pittings, scratches, and copper on the worn surfaces of the pure carbon strips are found by observation of an optical microscope. The greater the arc accumulated energy, the more pittings and the more serious damage there are on the surface.