Disturbing impact of ac railway power supply with a scott transformer on a supplying grid - laboratory tests

The paper presents investigation of the influence of the AC autotransformer power supply system on the energy quality in a public grid. The research includes construction of a laboratory model of AC autotransformer railway power supply system. The model consists of a power substation with a Scott transformer, overhead catenary system with the inductances of the contact wire, parallel feeder and running rails, autotransformers and two trains. The first one with the inverter-asynchronous drive and the second with the diode rectifier and DC motor drive. The influence of the AC autotransformer system on the public grid considering all types of the disturbing influence including voltage unbalance, voltage harmonic generation and power fluctuation in aggregated.