Consideration of harmonic distortions in electromagnetic simulation of artificial railroad structures

This study aims to develop models for defining harmonic distortions in electromagnetic modeling of artificial railroad structures, taking into account high harmonic generation of electric locomotives. The research objects included tunnels and galleries, as well as through-type and deck-type truss bridges. Calculations of sites having a flat relief were carried out for comparison. When developing digital models, an approach representing power supply systems in phase coordinates in the Fazonord software package (5.3.7.0-2024 version) was used. Sets of conductors grounded on both sides were used for constructions. Electromagnetic fields were defined by simulation of five down trains weighing 3192 tons and moving at intervals of 22 minutes. For several constructions, the maximum working values of electric field intensity at the studied sites exceeded the permissible value of 5 kV/m, i.e., 9.8 kV/m for the deck-type truss bridge and 5.9 kV/m for that of the tunnel type. Due to extended train intervals, magnetic field intensity had never exceeded the specified limit of 80 A/m. Our study revealed that high harmonics of electric locomotives provoke severe distortions in the hodographs of magnetic fields, while artificial structures significantly change field distribution in the section of the electric traction network. Thus, digital models of traction-energy systems were developed. These models make it possible to accurately define the dynamics of changes in electromagnetic field intensity in a space surrounding the electric traction network of 25 kV inside artificial structures consisting of many metal parts. The computer technology developed by the authors can be effectively used in the development of measures to ensure electromagnetic safety in artificial structures of electrified railway transport.