Coordinated Control of Battery Energy Storage System and Plug-in Electric Vehicles for Frequency Regulation in Smart Grid

This paper presents a coordinated control of battery energy storage (BESS) and plug-in electric vehicles (PEVs) for frequency regulation in a smart grid. The proposed control strategy aims to eliminate frequency fluctuation caused by the dynamic behavior of load and intermittent nature of renewable sources (RESs). Due to the limitations of a conventional source to respond important changes in generation or load, BESS is employed to regulate the frequency within an allowable limit by supplying and consuming active power to/from the grid. However, BESS may not cover all changes in active power, and moreover the conventional source has a slow response. Consequently, the frequency may lose stability due to an imbalance between generation and load resulting in a severe situation in the smart grid. To circumvent this issue, in this paper, PEVs are therefore coordinated with BESS and adopted to be an ancillary service for frequency regulation. The proposed control allows PEVs to only operate under charging state, and hence PEVs are controlled to reduce their charging power via an aggregator according to droop characteristic. The proposed control strategy is validated in the simplified smart grid performed by DIgSILENT powerfactory software. The simulation results demonstrate that the proposed control strategy can improve frequency regulation effectively using comparative study. Finally, the proposed control strategy can reduce the BESS energy capacity related directly to decrease in power utilization.