Centralised Control Strategy for an Urban Rail Network in the Presence of Onboard Storage Systems

In line with the growing emphasis on energy efficiency in the railway industry, light rail and metro operators are actively seeking ways to optimize their energy use. Unidirectional traction power stations (TPS) significantly reduce the receptivity of traction networks, leading to an ineffective recovery of regenerative braking energy. This limitation becomes especially relevant in urban rail transit systems characterised by frequent starts and stops, where regenerative braking could substantially enhance efficiency. To address this challenge, the adoption of storage systems onboard rail vehicles is considered one of the predominant solutions. This work introduces a centralised control strategy for the optimal management of power flows in the presence of onboard accumulators. The strategy regulates the energy transfer between the traction circuit and the trains, ensuring that the operating voltage remains within acceptable operational limits. To this aim, individual trains are managed as distributed agents that are collaboratively operated for comprehensive energy optimisation. The numerical results of a case study based on Metro Line 1 in Naples, Italy, support the effectiveness of the proposed strategy.