Development of a short circuit simulation tool for railway DC electric traction infrastructure

DC is the preferred power supply topology for many railway systems such as tram, metro or certain heavy trains. One of the challenges encountered during the design of these systems is to properly simulate their behaviour during short circuit events. The grounding system must be sized and protection devices need to be defined for every project. Studying the current behaviour during short circuit events in a precise way requires a large number of iterations. A simulation tool based on Modified Nodal Analysis (MNA) has been designed for the specific case of a DC power system with a continuous ground conductor running parallel to the feeding system throughout its whole length. The algorithm is able to calculate the short circuit currents at any point of the line and to define the minimum cross-section required for the ground conductor. The program will make a continuous simulation of the line including different power supply configurations and output graphical information about the maximum currents in each conductor and the required ground cable for each scenario at each point of the line.