An Inductance Forcedly Absorbing Current Circuit to Reduce the Stray Current in the DC Power Supply System

In DC power supply system, because of imperfect insulation between rails and the earth, stray current emerges and causes damage to buried metallic facilities. This paper establishes a mathematical model of stray current distribution. A circuit based on inductance forcedly absorbing current is researched for DC railways. According to the Matlab/Simulink, it is proved that the circuit not only can achieve the purpose of reducing the rail current as well as reducing the stray current, but also the installation location and number of the circuit will affect the distribution of the stray current. In the unilateral power supply mode, the distance between the train and the circuit shorter, the current on the whole rail smaller. The more number of circuits, the current on the whole rail also smaller. On the basis of unilateral power supply mode, the rail current can be further reduced by taking the bilateral power supply mode.