The propagation of harmonic currents generated by inverter-fed locomotives in the distributed overhead supply system

Pulse-width-modulated converter-fed locomotives generate current harmonics that give rise to traveling waves in the overhead supply system. The waves are partially reflected at the feeding substances, causing parallel and series resonances at various discrete frequencies. An investigation based on the wave propagation approach demonstrates the influence of the track topography and the varying position of locomotives within the track. The distribution of harmonic currents in the overhead supply system is evaluated and discussed. These currents are shown to be much higher in certain locations of the railway track than the harmonic current injected by a locomotive. They may also appear at distant tract locations. The natural resonances in the overhead supply system determine the intensity of electromagnetic interference with the track-side communication lines