Different Models for the Simulation of DC Railway Systems Supplied by Non-Reversible Substations

Simulation is a valuable way to develop efficient design of the infrastructure and operations of electrical railway systems. Nevertheless, the size of such systems and the complexity of the power flows lead to complex models that require simplifications. A specific scenario has been identified as particularly difficult to study with most of the existing simulation tools. This scenario consists in a line with low energy recovery capacity in which all the substations are blocked. In such case, the railway system is disconnected from the AC grid and becomes an islanded system in which the braking trains, and eventually energy storage subsystems, supply other trains in traction mode. This paper aims to compare different modelling approaches to simulate DC railway systems in this specific scenario. The results highlight that conventionnal approach is not able to deal with this scenario. Another approach, based on a dynamic model from previous research works, is well able to estimate the system behavior with this scenario, but it leads to long computational time. Finally, an intermediary approach is proposed to simplify the model in such scenario and potentially reduce the computation time.