Statistical model for harmonic propagation studies in electric traction supply systems

The paper deals with the disturbance spectrum associated to the supply system for electric traction in different operating conditions. In particular, an experimental data set is used to analyze the electric systems for transportation currently in use in Italy, based on static power conversion stations (ESS) and dc supply feeders. In these traction systems the train supply voltage has harmonic spectrum characterized by the switching pulse of the rectifier bridges, by possible disturbances that affect the ac supply network and by the interaction between the converters on board devoted to supply traction motors and auxiliary services on the trains. The paper presents a software program that determines the regression linear indexes by a statistical model permitting to define the harmonic disturbance components in any general operating condition. The statistical model is set and compared with measurements performed on a real railroad plant.