A TLM APPROACH FOR THE MODELLING OF HIGH AND LOW FREQUENCY EMC PROBLEMS IN POWER SYSTEMS

The electromagnetic compatibility (EMC) analysis of complex systems such as the electrified railway, where trainset, power supply systems, telecommunication network, and train detection and control systems are closely coupled by a variety of mechanisms, requires a detailed knowledge of the internal couple relationships of the system components. The lack of information precludes any rigorous deterministic prediction of electromagnetic interference (EMI), and it requires a test campaign in order to verify compliance with the limits fixed by international standards on EMI. Nevertheless, the difficulty in carrying out measurement in a reproducible way and the cost of a possible system redesign if a violation of the EM emission is found, suggest the need for a characterization of the EM environment right from the start of the project phase. For this purpose, it is necessary, starting from the models of the main noise source and victims, to provide a methodology capable of describing in an easy way the main coupling mechanisms between the noise sources and the susceptible victims, taking into account both low frequency and high frequency phenomena. On this basis, the paper proposes a new methodology for the EM characterization of the electrified railway systems. In particular, it presents a method based on transmission line modeling (TLM) able to model the EM interaction between electrical circuits that model the sources and the victims of EMI. The paper presents a software tool that implements these algorithms and discusses the results of some simulations.