Hierarchical Model Predictive Control for Coordinated Electric Railway Traction System Energy Management

The paper presents a railway energy management system based on hierarchical coordination of electric traction substation energy flows and on-route trains energy consumption. The railway system is divided into energy-efficient individual trains energy consumption management as lower level, and the price-efficient electric traction substation energy flows management as higher level. The levels are coordinated through parametric hierarchical model predictive control with the main goal of additionally increasing the energy efficiency and decreasing the operational costs of the overall system. Through interactions with the power grid on the higher level, the system is able to provide ancillary services and respond to various grid requests. At the same time, lower level trains driving profiles are adjusted to attain the minimal cost of system operation with timetables and on-route constraints respected. The developed algorithm is verified on a detailed real case study scenario put together with a railway operator and a trains manufacturer. The presented results show significant cost and energy consumption reductions achieved by simultaneous coordination of several trains supplied from the same traction substation.