Filter design for harmonic reduction in high-voltage booster for railway applications

This paper presents the design of the power section of a 25-kV, 50-Hz, 10-MVAr single-phase static var compensator (SVC) for railway applications. It is based on a third harmonic filter, on a low-pass filter for harmonic reduction, and on a saturable reactor connected in series with the thyristor-controlled reactor. Harmonic filtering is the crucial aspect of the system because of the very stringent limitations imposed on the harmonic current generation due to railway signaling requirements. The effectiveness of this innovative solution in reducing the grid harmonic current injection is shown in the paper and the advantage, in terms of system efficiency, is underlined. The system was successfully constructed and installed at the end of 2002, and the commissioning will be completed during 2003.