Study Of Off-line Characteristics Between Pantograph And Catenary And Sensitivity Analysis Of Parameters Under High-speed Railway

With the rapid development of economy and the acceleration of urbanization,high-speed railway is of great significance to guarantee the sustainable and healthy development of national economy and improve people's living standards.The pantograph-catenary relationship is one of the key technologies to ensure the stable current collection and safe operation of trains.With the increase of train speed,the fluctuation of catenary and pantograph vibration become more intense,and the off-line phenomenon between pantograph and catenary causes frequent off-line arcs,which affects the current collecting quality of pantograph and catenary.Therefore,the contact force changes and off-line characteristics during high-speed train operation are analyzed based on the pantograph-catenary dynamic motion theory and current collecting status,and sensitivity method is used to quantitatively analyze the impact of pantograph-catenary parameters on current collecting quality,which is improved to meet the requirements of high-speed train operation,the main works are illuminated as follows:Firstly,in order to analyze the variation law of pantograph-catenary vibration which is used to explore the influence on current-collecting quality,the influence of catenary stiffness and its change rate on pantograph vibration and the dynamic motion of catenary under pantograph influence are analyzed respectively.Based on the above analysis,the pantograph is used as the external excitation of the catenary,and the catenary is assumed to be a multi-span continuous beam combined with the natural vibration characteristics to analyze of dynamic vibration law of catenary,and the relationship between the dynamic characteristics of the catenary and the running speed and the vibration frequency of the pantograph is obtained.Furthermore,the sensitivity analysis method is used to quantitatively analyze the influence degree of the parameters on the vibration movement of pantograph-catenary.Secondly,in order to explore the relationship between the contact force and its change rate and various parameters and to obtain the optimization method of current collection quality of pantograph-catenary in high-speed railway,the index which can describe the current collection quality more accurately is put forward.The key signals of the contact force near the dropper points are positioning extracted to analyze the changes of contact force by using the time series analysis method,smooth pseudo-Wigner-Ville distribution,wavelet transform and Lipschitz exponent in the three aspects of time domain characteristics,time-frequency characteristics and singular characteristics.The relationship between the contact force change between the two droppers and the stiffness value and its change rate is obtained for the time domain characteristics of contact force,and the moving average and the moving standard deviation are used as the evaluation indexes.The relationship between amplitude component of dropper-spacing and span,Lipschitz index and catenary stiffness and particle inertia is obtained to analyze the contact force at the dropper points and its change rate on both sides by using the wavelet transform for the time-frequency characteristics and singular characteristics.The analysis shows that the change rate of stiffness between the two dropper points and the inertia of the catenary particles can be reduced,which can significantly improve the change of contact force at the dropper-points.Then,in order to analyze the off-line rule of trains running at high speed,off-line spacing,off-line time and off-line position are analyzed as off-line characteristic parameters.The off-line characteristic parameters are obtained by means of simulation calculation,which solves the problem that off-line characteristic parameters are difficult to obtain in actual measurement and experimental research.It is concluded that the off-line position,off-line distance and off-line time are affected by the stiffness of the catenary and the inertia of the particle of the catenary.Finally,the global sensitivity analysis method is used to quantitatively analyze the relationship between each influencing factor and contact force characteristics,off-line characteristic signals.It is concluded that different position parameters have different effects on contact force and off-line characteristic signals at different locations through analysis.That is to say,the corresponding optimization scheme should be designed according to the deteriorating position of the current collection quality when optimizing the structure of catenary.On the basis of this analysis,the optimization method of catenary structure is put forward to meet the requirements of high-speed train operation.Through analysis,it is found that the current collecting quality of pantograph and catenary based on simple catenary and elastic catenary can be improved by adopting appropriate design methods such as increasing the contact wire tension and reducing the messenger wire tension,which shows the accuracy of the optimization method.