Methodology for assessing the impact of regenerative braking energy injection of a direct current railway system on the distribution grid
Jesús Araúz, Sergio Martínez
Abstract
The increasing development of railway systems around the world is leading the scientific community to a growing interest in studying the coupling between different railway technologies and other systems such as energy storage systems, microgrids, and power systems to improve global energy efficiency. Many authors have considered regenerative braking energy as an important contributor to railway efficiency. Thus, its usage has been studied, mainly to reduce energy consumption, improve power quality, and even achieve catenary-free operation. Few studies deal with the interaction between railway systems and the distribution grid, and even less include a precise grid description. Therefore, this paper proposes a novel methodology to assess the impact of injecting regenerative braking energy into distribution grids, based on detailed modeling of the DC railway system and the grid, but simplified modeling of their coupling. The application of the proposed methodology is illustrated with a case study on the actual Panama Metro Line 1 to investigate the impact on a surrounding distribution grid inspired by Panamanian common configurations. The results indicate the feasibility of injecting all the surplus energy into the grid, characterizing the resulting voltage fluctuations.