Handling large railway supply systems-a challenge for system modelling and a need to guarantee rail vehicle´s system compatibility

Over the last few years more and more focus has been put on the problematic of handling large and complex network topologies like the electrical railway supply network. A better understanding of the complete railway network is an absolute necessity due to increasing requirements for electrical system compatibility of the vehicles running on the network. These requirements include the well known questions of disturbance current limits and also questions of overall system stability. In order to fulfil them a great deal of effort in system modelling is needed during the vehicle´s tendering and design phase. The large number of independent variables in a large railway network forces the engineer to simplify the problem to some extent. One question is how, where and how much the models can be simplified. The paper describes some of the problems including how they can be handled in a simple way but still represent the real system with acceptable model errors