A procedure for the wear prediction of collector strip and contact wire in pantograph-catenary system

The effects of friction and electrical phenomena like arcing and sparking govern the wear rate in the sliding contact between the contactwire and the collectorstrip, these two effects are mutually interconnected in a complex manner. A means of investigating the wear of the collectorstrip and the contactwire is to carry out laboratory tests that allow to perform comparative tests between different material combinations and to establish the dependence on the main parameters such as sliding speed, contact force and current intensity. A problem to be considered in the application of the laboratory test results is their extrapolation to the real operating conditions, in order to assess the effective benefit among different solutions. In this paper, aprocedure that combines awear model for the contact between collectorstrip and contactwire with the simulation of the dynamic interaction between pantograph and catenary is proposed. The adopted wear model is based on the wear map concept, including the effect of electrical current flow, and it is tuned by means of the results obtained on laboratory test rig. The dependence of the electrical contact resistance on the contact force between each contactstrip of the pantograph and the contactwire of the overhead line is considered and the corresponding electrical current on each of the two collectors of the pantograph is evaluated. Instantaneous values of contact forces and electrical current are then fed into the wear model and the amount of the wear of the collectorstrips and of the contactwire along the overhead line is calculated, generating an irregular profile of the contactwire. The proposed procedure is applied to two cases: in the first one the wear of the contactwire using copper collectorstrips and graphite collectorstrips for dc line are compared. In the second one, the consequence of the variation of the mechanical tension of the contactwire on the wear levels is predicted.