A Ground Fault Location Method for DC Railway Systems

The application of Direct Current (DC) railway systems is more and more noticeable as they conform most of urban tram feeding systems and, step-by-step, it is being introduced in high-speed train power systems. Despite of their high efficiency, the risk of ground faults is latent due to environmental problems and aging in the catenary. These faults can interrupt the service for hours until it is repaired, then a quick maintenance is needed. In order to help in this issue, this paper proposes a ground fault location method for catenaries in DC railway systems based on the DC voltage and earth current measurement in each DC traction substation (TS). The normalized currents respecting the global fault current are compared with a model-based data pool allowing the method to locate the fault along the protected catenary. To corroborate the method, simulations have been performed in a three-TS DC railway model in Matlab-Simulink obtaining promising results.