Measurement and Analysis of Magnetic Field Radiated from D.C. Tramway: A case study for Tunis’s metro

High-power electrical drives, subsystems, and equipment mounted on board of rolling stock make the internal environment potentially harsh from the point of view of electromagnetic (EM) field emissions. In particular, at low frequencies, electronically controlled power drive systems behave as effective emission sources. This paper deals with characterization of electromagnetic field radiated from D.C. railway systems. The D.C. railway system of Tunis’s urban electric metro is described. The magnetic field is measured at different points inside and near the moving D.C. train. Measurement results are presented and analyzed. Analysis of measurement results shows that, within frequency range 100kHz-20MHz, the radiated magnetic field is coming from power electronic systems embedded on the train. In particular, choppers, D.C. motors and their connecting cables represent the most important emitting source of magnetic field in the D.C. tramway.