A single phase pll based active power filter solution for power quality problems in railway electrification systems using scott transformer

Transportation is one of the biggest energy consumer especially automobiles. In a world where energy conservation and environmental protection are growing concerns, the development of electric vehicle technology has taken on an accelerated pace. Electrified railway system has big advantages to save energy, environmental factor and mass capacity compare with their rivals for example automobiles and aircrafts. Therefore the electrified railway has increased its share and importance on transportation system at last twenty years. Due to growing capacity and complexity of the railway systems, it introduced us with power quality problems. Power quality is become more a critical issue and it requires more careful control.The aim of this paper is to introduce electrified railway system and mitigate the power quality problems in the 25 kV AC railway system and decrease the harmful effects to utility electric network using proposed topology. The method has two different parts. First one is an EPLL based single phase active power filter that can compensate the load reactive and harmonic current. The second one is Scott transformer can decrease unbalanced voltage on the network.The performance and efficiency of the proposed method are investigated with simulation studies by PSCAD / EMTDC.