The Numerical Simulation Study On The Stray Current Of Metro

With the DC power supply of subway, the running rail may produce stray current, not only led to loss of structural steel even reducing the safety of the structures but also result in perforation of the underground pipeline and causing serious economic losses. Therefore, studying the distribution of the stray current will reduce the stray current leakage significance.It’s researched that the traditional simulation method has a huge flaw. In consideration of the limitations of traditional methods, this paper developed a simulation method based on Pspice. Kirchhoffs voltage law and current law are used to calculate of the voltage and current relationship in the complex resistor network, thus voltage, input current and output current at any node are obtained.The simulation method based on Pspice simulates working conditions in unilateral and bilateral power supply. The distribution of stray current under various rail-ground resistivity, the supply current and the distance between traction substations is drawed. It mainly concludes:(1) The simulation method based on Pspice and the simulation method based on differential equation in drainage and no-drainage reach a very small data error that is less than5%. It’s showed that the simulation method base on Pspice is effective.(2) Under electrical insulation without current drainage, the distribution of rail current and stray current is parabolic. In the mid-point railway current is at a minimum, and stray current is at a maximum.Under electrical insulation with current drainage, the distribution of rail current and stray current is semi-parabola. The distribution of rail potential is straight line, at the traction substation is zero, at the train is the maximum value, and the maximum is as twice as the value without current drainage.(3) With the leak points increased, the rail current is reduced, stray current is increased. With the decrease of the rail-ground resistivity, the rail current is reduced, stray current is increased. With the increase of locomotive current, rail current, stray current, the maximum rail potential proportional to the growth. With the increase of power supply length, the rail current is reduced, stray current is increased.(4) Compared with the unilateral power supply, bilateral power supply can effectively reduce the rail potential and stray current.