Research On The Key Technology Of Single Return Rail System In Urban Rail Transit

With the rapid development of China’s urban rail transit system,the metro lines length and the number of metro are increasing,the stray current problem caused by part of the current flowing into the earth when the current return through the running rail is becoming serious.Therefore,more and more people pay attention to the research of stray current protection and treatment measures.The harm of stray current includes corrosion of structural reinforcement and pipelines along the line,resulting in the rise of ground potential,which not only affects the normal operation of the equipment,but also affects the traffic safety in serious cases.The traditional solutions include installing drainage network,shortening the distance of substation and increasing the rail-ground insulation level.However,these protective measures only reduce the amplitude of stray current,which is difficult to solve the long-term corrosion effect of stray current fundamentally.Therefore,in order to solve above problem fundamentally,this paper designs a single return rail system for traction power supply,and studies the key technology of the implementation scheme of the system.In this paper,firstly,the metro system is optimized and improved from the hardware equipment to cooperate with the design of power supply for single return rail.The hardware equipment is mainly divided into two parts: train and single return rail.Aiming at the train equipment,based on the B-type train operation,and referring to the power supply technology of the third rail,the return vanes is added to the train,and the installation mode and installation position of the return vanes are selected,and the reliability of the design scheme of the return vanes is verified through field test.Then the main circuit of the train is improved so that the improved train can run on the lines of the traditional running track.Aiming at the equipment of single return rail,the steel aluminum composite rail,intermediate joint,expansion joint,anti-creeper,end elbow,insulation support,protective cover and other components are studied.The return scheme of single return rail and the installation scheme of single return rail in various line sections are selected.Finally,the safety and maintenance measures of single return rail are formulated to ensure the safe and stable operation of power supply return system of single return rail.In the design of power supply scheme of single return rail system,the method of combining test and simulation analysis is adopted.Firstly,a specific urban rail transit line is selected to test and analyze the insulation performance and stray current situation of the running rail return system.Through the analysis of the reliability of the single return railpower supply system and the analysis of the reliability of the single power return rail supply system,the simulation results show that the system can meet the requirements of the system.In view of the possible grounding fault of single return rail system,the protection scheme and protection measurement and control scheme are formulated.Finally,the economy of single return rail system is analyzed to explore the actual engineering benefits of its construction.Through the above research,it is proved that the single return rail system can not only completely solve the stray current problem caused by the return current of running rail,but also improve the economy of the whole life cycle of rail transit,with good economic and social value.It is suggested that the system can be widely used,especially in the construction of new lines.