Modelling and Determination of Short Circuit Traction Line Parameters for the Italian 3 kV DC Railway System

In recent years, traction infrastructures for metro and railway systems are objects of relevant interest to improve public mobility according to the paradigm of smart grid and environmental sustainability. However, critical conditions due to short circuit faults may compromise the functionality of the entire power system. Therefore, protection systems have to promptly operate in presence of faults. This paper focuses on the Italian 3 $\mathbf{kV}$ DC railway traction power system. It aims to investigate the impact of traction line network parameters on the short-circuit current. With this regard, the system is, firstly, described according to the Multiconductor Transmission Line (MTL) model, and then represented by an equivalent lumped polyphase circuit. This circuit is used to determine the power line's equivalent resistance and inductance values, which can be used to set the protection devices installed at the Traction Power Substations (TPSs).