New Medium-Voltage DC Railway Electrification System

This paper highlights the potential of medium-voltage dc electrification for railway traction. A method is proposed for determining the dc voltage level in order to guarantee, in terms of traffic, equivalent performances to an ac-electrified railway line. Railroad traffic, type of transport service, and railway network topology being given, the analysis method takes into account the following constraints: voltage at the pantograph, heating of overhead line and rail-to-ground voltage. Once the dc voltage level is chosen, the dc electrification system is compared with a standard 25-kV ac electrification in the case of the French high-speed line from Paris to Strasbourg.