Measurements on 25 kV Traction Power Supply Systems

At the moment 25 kV traction power supply systems are being introduced in the Netherlands. Currently in the Netherlands a 1500 V DC system is used, however due to increasing energy demands this system is no longer sufficient. For the high-speed lines and heavy freight lines, which are under construction, the 2x25 kV AC system has been chosen. Introduction of this new technology leads to differences compared to the existing systems. Of particular interest are EMC topics such as influence of the traction power supply system on signalling systems, or systems in the close vicinity of the railway system. The latter is especially important in the Netherlands where the railway system runs through densely populated areas. A part of the first Dutch 25 kV line, the “Havenspoorlijn”, connecting the Rotterdam Harbour with the hinterland, will be used as a Pilot-Project. This line will be equipped with several measurement systems, to validate the system design. This project is financed by NS Railinfrabeheer. Preliminary measurements have been performed on the 25 kV system of the Luxembourg Railways, in a way similar to earlier experiments along a TGV track near Lyon, France. Prerequisite for measurements is that the normal traffic is not disturbed, and that the EMC of the system complies with the harsh EM conditions in the very close neighbourhood of the railway. Special techniques and sensors have been developed which allow measurement of current distributions, voltages and magnetic fields, without hampering the normal traffic. Measurements have been performed on a 25 kV RT system and a 25 kV AT system. For the RT system the measurements were done during normal traffic conditions. For the AT system the measurements were done during the daytime with the normal schedule. During the night a light engine was used, and different switching configurations of the supply system could be created.