Research On Failure Mechanisms Of Lateral Electrical Connectors Of High-speed Railway Catenary

The catenary electrical connector is an important component of the catenary system.The electrical connector can improve the current distribution in the contact suspension.Through the electrical connectors,serial and parallel power supply can be achieved,which can reduce power loss and improve power supply quality.In recent years,with the increase in the years of operation of high-speed railways,the problem of failure due to electrical connectors in contact suspensions has become increasingly prominent.In view of this,it is necessary to study the failure mechanisms of the electrical connectors of the high-speed railway catenary,which is helpful to solve the problems of frequent strand breaking and fracture failure of the electrical connectors of the high-speed railway catenary,and provides a theoretical basis for improving the service life of the electrical connectors.This article takes the lateral electrical connector as the research object which are widely used in high-speed railway catenary.Through the methods of on-site investigation,theoretical analysis,model establishment,parameter calculation,observation verification,and test verification methods,combined with the knowledge of mechanical action,electrical action,chemical corrosion and other fields,a systematic study on the failure mechanisms of electrical connectors was carried out.Firstly,based on the working conditions of the electrical connectors site and the relevant theory of the failure mechanisms,a comprehensive analysis of the potential factors that may cause the failure of the electrical connectors is carried out,and hypotheses are proposed;Secondly,the Keyence VHX-700 FC three-dimensional microscope and Zeiss Gemini SEM 300 field emission scanning electron microscope was used to observe the microstructure of the faulty electrical connectors fractures,and the energy spectrum analysis of the material at the fractures was conducted to verify the hypothesis of fretting wear,bending fretting fatigue and environmental corrosion as failure factors of electrical connectors failures;Next,through the establishment of models and parameter calculations,the effect of the pulse current on the lateral electrical connectors in the contact suspension is obtained;Finally,according to the calculation results,first apply a cyclic pulse current pretreatment to the electrical connectors,and then disassemble the preprocessed electrical connectors into wires,clamp them on the Tianxing MC-10 electronic universal tensile test machine for tensile test,and draw the sample of the stress-strain curve,it was found that with the increase of the number of pulse current pretreatment,the tensile strength of the electrical connectors decreased,the plastic deformation ability is improved.This mechanical property test verified the hypothesis that the purely electroplastic effect of pulse current will change the mechanical properties of the copper alloy material for electrical connectors,which will lead to failure of the electrical connectors and reduce the service life of them.Through this study,it was found that the working environment of the electrical connectors is extremely complicated.While being corroded by acid rain and salt spray,it is also affected by the impact current and bending fretting fatigue.Therefore,the failure of the electrical connectors is the result of a combination of factors.Among them,the crimping process,fretting wear,bending fretting fatigue,electroplastic effect,environmental corrosion,and material defects of the electrical connector are the main factors leading to failure of electrical connectors.