Effectiveness of filters in 3 kV DC railway traction substations supplied by distorted voltage-measurements and diagnostics

Abstract

Electric energy quality criteria relating to a DC supply system concern the circuits from the rectifiers installed in traction substations till the vehicle's current collector. Energy Law and related implementing provisions unequivocally state that an electrified transport system, as the energy recipient, shall fulfil energy consumption requirements that are defined in the agreement. It imposes certain conditions for the railway power supply company. Introduction into traffic of the traction vehicles that are equipped with converter power electronics drive systems increased requirements regarding voltage quality in a DC catenary. At the same time, increase in share of non-linear recipients causes the increase of distortions in AC voltage supplying traction substations, which also transfer to the DC side. In some cases, disturbances in operation of low power infrastructure, such as signaling and control circuits, were observed, although energy quality parameters at the AC side have been fulfilled. All these factors caused a change in operational conditions of the resonance smoothing filters hitherto used in the rectifier traction substations that are supplied by AC medium voltage power lines. This paper presents a research and a case study of the problem of effectiveness of functioning of the applied resonance filters, from measurements, allowing for problem identification, to the results of the studies of the proposed new solution of a filter and the results of the observed exploitation of a prototype with the application of a digital monitoring and diagnostics system. Copyright: