Coordinated operation of a hybrid energy storage system and a hydropower plant for the provision of frequency containment reserves

Abstract This paper studies the coordinated operation of a hydropower plant, equipped with two Francis units, a battery and a supercapacitor, all providing frequency containment reserves. A simulation model of the hybrid power plant is used for this purpose. The simulation model of the hydropower plant is based on a real hydropower plant. The simulation models of the battery and the supercapacitor are based on the results of laboratory tests performed on commercial cells. The control system is based on previous works by the authors and has two goals. One is distributing the power set-point for the provision of frequency containment reserves between the Francis units, the battery and the supercapacitor. The purpose of this distribution is minimizing the wear in different components of the hydropower plant and the battery aging. The other goal of the contol system is keeping the state-of-charge of the battery and supercapacitor within a pre-specified band with the help of the Francis units. The paper studies the influence of the supercapacitor sizing on the performance of the hybrid power plant, scrutinizes the control system, and suggests possible solutions to further improve the performance of the hybrid power plant.