Comparative Study on the Position of Shunt Active Power Filters in 25 kV AC Railway Systems

AC electrified railway systems show power quality problems such as harmonic current pollution, feeder voltage
perturbation, and reactive power demand. These power quality problems have a bad effect on the AC
railway system itself as well as other electric systems connected together. This paper investigates comparatively
two configurations of a shunt active power filter (SAPF) for improving power quality in the AC railway
systems. Different control algorithms corresponding to the installation position of the active power filter at
the substation or at the sectioning post are proposed respectively. A comparative case study on the two
positions of SAPF has been performed comprehensively.