Simulation Research On The Influence Of Contact Forces Between Overhead Contact System And Pantograph Caused By The Abnormal State Of Catenary

With the rapid development of electrified railways,our expectations for faster,safer and more reliable electrified railways are increasingly growing.As a crucial part of the electrified railway,the overhead contact system has frequently appeared the abnormal status in the actual operation process,which has seriously affected the current collection between the pantograph-catenary and thus reduced the reliability of electrified railway operations.Studying the current collection quality of pantograph-catenary under the abnormal conditions is able to provide the basis for judging the extent of harm caused by the abnormality of the overhead contact line,providing the reference for fault prediction and fixed-point maintenance of the overhead contact line and has great significance for improving the security of overhead contact system.At present,scholars at home and abroad has mainly focused on the research of the mechanism and phenomenon of abnormal conditions of overhead contact line,while rarely made a quantitative analysis on the quality of the current collection quality of pantographcatenary.The thesis will establish an abnormal state model of overhead contact line with the help of ANSYS and explore the influence of different anomalies on the quality of pantograph-catenary by the contact force to characterize the current collection quality of pantograph-catenary,giving a reference for judging the abnormal conditions of overhead contact line and putting forward improvement measures to enhance current collection quality of pantograph-catenary and increase the reliability of overhead contact system.A brief introduction is made to the frequent abnormalities of overhead contact line in the practice of the project.A simple catenary suspension overhead contact line,a rigid overhead contact line,overlapping sections and rigid-flexible transition models were established based on ANSYS-APDL,and the sliding of the pantograph along the contact lines was achieved by coupling method.Based on the model of flexible overhead contact line under the normal conditions,the three types of contact suspension abnormalities such as contact line wearing,suspension string breakage,and suspension string falling off were simulated.It was found that when the wearing of contact lines reached 28% of the sectional area of initial contact lines,the current collection quality of the pantograph-catenary was significantly getting worse;the closer the suspension string located near the center,the poorer the quality of the pantograph-catenary;in the analogue simulation of the abnormalities of support device base loosening of the catenary wire,it can be found that the failure point cannot collect the current when the catenary wire base fallen off;in the analogue simulation of the parameters abnormalities of tensile structure between contact line and catenary wire,it was found that increasing the tension of contact line and catenary wire can effectively improve the current collection quality of pantograph-catenary.For rigid suspension overhead contact line,the impact of span variation of rigid suspension overhead contact line on the current collection quality of pantograph-catenary was simulated and analyzed.It was found that within a span of 6m to 10 m,the smaller the span was,the better the flow quality was,but the question that the resonance would degrade the current collection quality shall take into account when the span excitation frequency was close to the natural frequency of the overhead contact line.In the simulation of the impact of the looseness of the positioning insulator,overlapping sections and the installation deviation of the rigid-flexible transition on the current collection quality of pantograph-catenary,it is found that appropriate reduction in suspension stiffness can effectively improve the current collection quality of pantograph-catenary.When the positioning insulator loosened and the suspension stiffness was too small,the current collection quality of pantograph-catenary would deteriorate sharply;the overlapping sections and the rigid-flexible transitions were the weakness of overlap contact systems.When the installation deviation was too large,the pantograph-catenary would not be able to receive the flow normally.It is proposed to improve the current collection quality of pantograph-catenary by the installation of elastic insulating suspension components.Studies have shown that different arrangements of elastic insulating suspension components have different degrees of improvement in the quality of current collection;installation of the component at the overlapping sections and rigid-flexible transitions can effectively improve the quality of current collection and increase the tolerance of overhead contact line under the abnormal conditions;under the premise of ensuring speed and current collection quality,the use of elastic insulating suspension components can increase the span of overhead contact system,reduce the number of failure points,and decrease the workload of construction and maintenance.