Hierarchical coordination of trains and traction substation storages for energy cost optimization

This paper is focused on improvement of energy- and cost-efficiency of an electric railway traction system with respect to electricity supply conditions, routes conditions, timetable requirements and overall system constraints. This is attained by coordination of electric traction substation energy flows management and on-route trains energy consumption to facilitate the integration of railways into smart electricity grids. Optimization of energy flows in the electric traction substation with respect to the grid-supplied electricity price profile is coordinated with multiple trains on-route power consumption. The coordination optimizes traction profiles directly to improve the electricity cost while all physical and on-route constraints are kept. For validation purposes, extensive simulation scenarios are conducted confirming significant energy saving and cost reduction potential of the presented coordination in different railway system operation set-ups including volatile price tariffs, different energy storage systems, different number of trains in the substation supply area and grid conditions.