Analysis of stray currents for traction vehicles

The operation of traction vehicles such as locomotives and trams makes the emergence of stray currents in the area of rails and under the rails. These stray currents can adversely affect cable lines near the rail for example. And therefore, the article deals with the structural simulation of stray currents in the rail and in the area under the rail. This area is divided into several sections which are interlinked and differ with their parametric properties that are defined in the simulation by using resistors. The simulation includes several longitudinal and vertical layers. The length of the simulated section is of 1 km. There are created two different simulations namely one for the railway track and there is one for the tramway track. The individual tracks are of the same length but of the different supply voltage. In stray currents simulation of the railway track the locomotives has a quaternion of series-parallel connected traction motors which are powered from the contact wire with the value of 3.3 kV. We use the quaternion of direct current traction motors which are powered from the contact wire with value of electrical voltage of 600 V in the simulation of tramway track. The simulations are carried out for dynamic states of operation of individual traction vehicles. At first the accelerating period with subsequent stopping is carried out and then the accelerating period up to steady speed is carried out. The individual start-ups are gradual and the leakage current into the rail is subsequently used when mathematical formulas are applied for the calculation of stray currents. Their results are indicated via graphic explication but they are also stated in the table of layers and in the maximal values of potential in nodes. The last graph shows the comparison of individual stray currents in the area under the rail when the different supply voltage is applied. The simulations are used to clarify and understand the stray currents when the asymmetrical loading con- itions are applied.