Digital Twin based Implementation of Active Traction Substation in DC Railway Systems

Electric railway systems (ERS), stand as a pivotal technology in the transportation sector. Given the extensive nature of these networks, conducting precise simulations becomes imperative for ensuring dependable and safe operations aligned with real-world performance. Meanwhile, the development of more eco-friendly sections with increased energy efficiency have become a goal for ERSs which are one of the high-consumption users for grid. Focusing on regenerative braking energy (RBE), this paper addresses the potential of bidirectional traction substations known as active traction substation (ATSS) with interleaved PWM rectifiers, allowing bidirectional power flow and promoting RBE revert to the main grid. In this paper, an approach is presented to develop a digital twin (DT) concept of bilateral DC railway system with ATSS which allows to receive the real data from physical system and estimate the transient events and power quality issues. Utilizing the current setup of the Italian 3 kV DC railway line as a realworld example, the study assesses different substation characteristics to pinpoint the optimal design, considering essential metrics like voltage ripple, stress on passive components, total harmonic distortion, voltage and current imbalances, and achieving unity power factor operation. Due to the inclusion of a real case study, the findings accurately reflect real-world parameters.