Hybrid power plant in FCR-N provision: An analysis of storage sizing in connection with turbine stress reduction

This paper examines the capability of a linear time-invariant (LTI) filter to reduce the stress of turbine units in hybrid power plants providing Frequency Containment Reserve (FCR) for primary control of the power grid. The main focus is to analyze the effect of filter parametrization on the stress reduction under the dynamic performance criteria given by the Nordic FCR requirements. Analytic derivations are targeted to gain insight into the dependencies of attainable stress reduction, and storage sizing as a function of the FCR test and filter parameters. The study revealed that the filter utilizes an available storage system inefficiently, resulting in low performance in terms of turbine stress reduction and high energy usage. The obtained results are valid for any turbine and storage combination with suitable characteristics for FCR operation since the analysis focused on power behavior. • Distribution of the load between turbine and energy storage using an LTI filter. • Analysis of filter parameters on the turbine stress reduction. • Examination of the filter performance regarding storage sizing.