Relevance of Harmonic Active Power Terms for Energy Consumption in Some Railway Systems

Active power is not carried solely by the fundamental component (either dc or ac) especially for highly distorted systems, as electrified railways. The paper proposes two indexes and a preliminary assessment of the relevance of harmonic active power terms. Results are shown for three major railway systems architectures (3 kV dc, 2x25 kV 50 Hz and 15 kV 16.7 Hz) using experimental pantograph voltage and current. Harmonic power terms are relevant for the estimate of energy consumption especially for ac systems rather than dc, with some significant situations especially for 16.7 Hz systems.