Measurement and modeling of low-frequency electromagnetic noise generated by moving trains in 25 kV ac high-speed railway lines

This paper deals with measurement and modeling of conducted and radiated emissions (CE and RE) of high-speed trains in the low-frequency range 9−150 kHz, which are mainly generated by power-electronic converters. Firstly, an experimental procedure and a post-processing method, based on the median filter, is proposed to improve procedures foreseen in current Standard IEC 62236-2. Specifically, magnetic-field RE are characterized by a time-frequency representation, and stationary emissions are separated from transient events. Finally, a simplified model for the prediction of CE and RE is presented and compared versus a previously developed multiconductor-transmission- line approach. It is shown that the proposed simplified model provides useful results, as long as the spatial distribution of the radiated field (and not the estimation of emission levels) is of interest.