Study On The Law Of Traction Backflow In Railway Station And Its Influencing Factors

Railway is the second largest means of transportation after highway,is an important infrastructure in China,in China’s comprehensive transportation system has a crucial position.By the end of 2019,the length of China’s railways in operation had reached more than 139,000 kilometers,and the length of its high-speed railways reached 35,000 kilometers,ranking first in the world.In recent years,in order to meet the needs of railway transportation,the railway station has been continuously expanded,the stock passages in the station have increased,and the backflow environment has become more and more complex.There are many problems in the station,such as the failure of traction backflow,the burning loss of rail insulation joint,the over-potential of rail,the damage of choke transformer and so on.At present,it is not clear about the proportion of backflow distribution in the traction backflow system of railway station.In this paper,the variation of the reflow distribution ratio and the unbalanced current of the rail in the general power supply section of the station is studied by the combination of simulation and actual measurement.Firstly,the electromagnetic transient analysis software EMTP is used to build the simulation model of the interval from the railway station trailer to the incoming signal.By comparing the simulation results before and after increasing the coupling lines,the influence of the coupling effect of different lines on the backflow distribution ratio of the lines in the interval section is studied,and it is found that the catenary and the power supply line installed along the line play a decisive role in the backflow distribution of the lines in the interval section.By comparing and analyzing the simulation results with the measured data,it is found that when the coupling effect between lines is not considered or the coupling effect between rail and backflow line is only considered,the simulation results have a large deviation from the measured data,and the simulation results considering the coupling effect between rail,backflow line,catenary and power supply line are consistent with the measured data.It shows that the coupling effect between catenary and power supply line must be considered when constructing traction backflow system.Secondly,the simulation model of traction backflow system in general power supply interval is built by using the above modeling method.In this paper,the influence of line length and line spacing on the backflow distribution ratio in the interval is studied by simulation,and a comparison table of the backflow distribution ratio between lines,line length and line spacing is obtained.According to the proportion of the reflow distribution between the lines in the table,the calculation formula of the current between the rail and the reflow line in the interval section is derived,and a calculation method of the current between the rail and the reflow line in the interval section is put forward.Finally,aiming at the problem of poor traction backflow found in the field investigation,the corresponding improvement measures are put forward according to the above research results.