Modeling of Electromagnetic Fields Occurring at Intersection of Traction Networks and Overhead Power Supply Lines

Abstract

Traction networks (TN) 25 kV generate higher electromagnetic fields (EMF) with frequency 50 Hz, the strengths of which at a standardized height of 1.8 m, as a rule, do not exceed the permissible norms for electrical personnel. In places where railroads routes intersect with high voltage overhead power supply lines (OPL), the interference of fields, generated by the traction network and OPL, occurs. This can lead to an increase in strengths and a complication of the EMF spatial structures. The article presents a methodology for determining the strengths created at intersections, and modelling results performed for typical situations when a TS of 25 or 2x25 kV is intersected by an overhead power line of 220 kV at an angle of 90 degrees. The algorithm for calculating the resulting EMF strengths includes the following steps: calculation of TN and OPL modes in phase coordinates, the results of which determine the potentials and currents of all wires; the calculation of the vertical and horizontal components of the EMF strengths; calculation of amplitude values of strengths at the intersection point taking into account possible elliptical polarization. The modelling results show that the maxima of the amplitudes of the magnetic field strength at the points of intersection by the traction network of 25 kV and OPL of 220 kV reach 83 A/m. A similar parameter for the electric field equals to 5.4 kV/m. For a 2x25 kV traction network, these values are reduced to 32 A/m and 4 kV/m, respectively. This work was financially supported by the grant “Improving the quality of electric energy and electromagnetic safety in railway power supply systems equipped with Smart Grid devices by applying methods and means of mathematical modeling based on phase coordinates”.