Research On The Contact Resistance And Optimal Pressure Load Of The Pantograph And Catenary System

The characteristics of the contact resistance between pantograph sliding plate andcontact wire directly affect the current-carrying performance of the pantograph catenarysystem. Wear experiment with metal impregnation carbon strips and Cu-Sn alloy contactwire was conducted and the relationships between different experimental conditions andcontact resistance were researched. The following conclusions were obtained byanalyzing the experimental results. Under zero contact current conditions, if pantographsliding plate and contact wire keeps in relative static state, contact resistance willdecrease with the increase of pressure load. And if the pantograph sliding plate andcontact wire keeps in relative sliding state with a constant pressure load, contactresistance will increase with the increase of sliding speed. But under strong currentsliding contact state conditions, contact resistance will decrease with the increase ofcontact current with a constant pressure load and sliding speed. Then, a calculationmodel of the contact resistance was built by analyzing the influence of pressure load,sliding speed and contact current on contact resistance. The model parameters weresolved by the improved Gauss-Newton iterative algorithm and the validity of thecalculation model was proved.The large wear of sliding plate and instability of current-carrying inpantograph-catenary system is a key problem, which has restricted the development ofthe electrified railway to high speed, heavy load, safety and stability, and should besolved by adopted effective measures in our country. The friction coefficient and contactcurrent of the current-carrier friction pairs are fluctuation when it sliding at high speed,the reason is that the vibration which caused by the mechanical action between the tworough friction surfaces. The performance of current-carrying would become worse andthe mechanical wear, electrical wear would become greater when the vibrationamplitude which has direct relation with the pressure load and the condition of contactsurface is very large. So, it is necessary to take the optimal tribological properties (theminimum of wear rate of sliding plate) and the optimal current-carrying properties (theminimum of stability coefficient of current-carrying) into comprehensive considerationto determine the optimal pressure load. Wear experiment with metal impregnation carbon strips and Cu contact wire was conducted and the influence law of wear rate ofsliding plate which characterize the wear speed of the pantograph sliding plate andstability coefficient of current-carrying which characterize the performance of theelectric locomotive current collection caused by pressure load under the specific contactcurrent and sliding speed were researched. The experimental results showed that underthe special contact current and sliding speed conditions, the wear rate of sliding platewhich characterizes the wear speed of the pantograph sliding plate decreases first andthen increases, which shows the changing trend of U-type while the pressure loadincreasing. But the stability coefficient of current-carrying which characterizes thestability of the contact current will decrease with the increase of pressure load. So thereis a suitable pressure load to make the wear of sliding plate and stability ofcurrent-carrying relatively optimal. So, based on a number of experiment data underdifferent conditions, a BP neural network nonlinear model was built, whose inputs werepressure load, contact current and sliding speed, and outputs were wear rate of slidingplate and stability coefficient of current-carrying. And then the particle swarm algorithmwas used to optimize the multi-objective problem when the contact current and slidingspeed were given. At last the Pareto set with the best pressure load were obtained tomake the wear rate of sliding plate and stability coefficient of current-carrying minimal.