Research On The Characreristic And Effect Mechanism Of The Contact Resistance Of Pantograph-Catenary System

The system consisting of pantograph and catenary is the link of electric locomotives getting power from outside, and an important mechanism ensuring electric locomotives running fast and safely. As an impotant and basic parameter of electrical contact in pantograph-catenary system, the value of pantograph-catenary system’s contact resistance can be regarded as an indicator of contact performance of pantograph-catenary system. Oversized or unstable contact resistance in pantograph-catenary system will not only reduce the quality of trains receiving current, but also shorten the service life of the pantograph skateboard and catenary wire. Therefore, the research of contact resistance in pantograph-catenary system has important practical significance.This paper describes the pantograph-catenary electrical contact test systems developed by my laboratory. Because of the special structural design in catenary wire’s motion device, the test system can simulate the "flexible, flat and linear contact" feature in pantograph-catenary system comparing with other similar test machine.Through theoretical analysis, this paper describes the contacting situation of pantograph-catenary system, studies the features and generation mechanism of contact resistance of pantograph-catenary system:The contact resistance of pantograph-catenary consists of the shrinkage resistance generated by the changed distribution of traction current density in conducting spots and the surface membrane resistance, and gives a theoretical formula for estimating the number and radius of the conductive spots in the contact surface.By the trial observing the static and dynamic contact resistance of pantograph-catenary system on conditions of different contact pressure, traction current and sliding speed, the effecting laws of these factors were expounded, and the effecting mechanisms of them were analyzed. Studies have shown that:The dynamic contact resistance of pantograph-catenary is greater than the static one on the same conditions significantly; The static and dynamic contact resistances of pantograph-catenary both decrease with increasing pressure, and the rate of decline tend to smooth; The static and dynamic contact resistances of pantograph-catenary both decrease with increasing current, meanwhile the rate of decline tend to smooth; The dynamic contact resistance of pantograph-catenary increases with increasing speed, and the rate of raising tends to steep; Faster the speed is, steeper the tendency that the dynamic contact resistance of pantograph-catenary decreases with the increasing current is.In this paper, through the trial and theoretical analysis, the dynamic contact resistance mathematical model of pantograph-catenary system concerning contact pressure, traction current and sliding speed was established. After analysing and comparing several iterative algorithms for solving nonlinear equations, this paper applies MatLab and uses LM(Levenberg-Marquardt) algorithm to estimate unknown parameters in the model by fitting trial datas. Through experimental verification, the dynamic contact resistance mathematical model of pantograph-catenary system established in this paper is valid.