Study On Stray Current Of Urban Rail Transit And Rail Potential Suppression Measures

At present,China’s economy is developing rapidly,and a large number of people are moving to central cities,which resulting in urban traffic congestion and limited economic development.To solve this problem,developing urban rail transit is the best choice for major central cities.However,the intensive increase in passenger flow will lead to serious overloading of the train,and the traction current required by the electric locomotive will increase accordingly.The technical difficulties it brings cannot be underestimated.For example,stray currents are increasingly corroding structural steel bars and pipelines of underground railways,and high rail potentials are gradually increasing the harm to personal safety and equipment along the line.Based on the advanced mathematical micro-element method,the mathematical model of stray current and rail potential distribution is established,and the mathematical expression of stray current and rail potential distribution is derived.Secondly,the article uses MATLAB to simulate the mathematical model,study the factors that affect the magnitude of stray current and rail potential.Finally,the model is verified in combination with reality,which provides theoretical guidance for reducing stray current corrosion and preventing excessive rail potential.The study found:(1)The reduction of the rail-to-ground transition resistance,the increase of the longitudinal resistance of the drainage network,and the increase of the locomotive current draw will increase the stray current of urban rail transit.(2)The increase in rail-to-ground transition resistance,the increase in rail longitudinal resistance,and the increase in the locomotive current draw will cause the rail potential of urban rail transit to rise.(3)The stray current function I_mis a monotonously decreasing function about the position x of the electric locomotive,and the rail potential distribution function U is a monotonously increasing function about the position x of the electric locomotive.The effective value of stray current and rail potential near the traction substation tends to be larger.