Sizing of a photo voltaic-storage system for power system frequency support

Power system frequency quality has become topical due to the installation of variable renewable generation. The present paper contributes to the topic by investigating the sizing of a photovoltaic energy storage (PV-ES) system for frequency maintenance. The core content of the paper is threefold. Firstly, an algorithm is proposed to optimize storage capacity required to provide virtual kinetic energy and droop response for the frequency support. Secondly, the required storage and corresponding power capacity are assessed in the case of the frequency dynamics of the Nordic power system. Particular attention is given to the sizing requirements for virtual kinetic energy, replacing the displaced kinetic energy of conventional power plants. Thirdly, a case study is performed to showcase the sizing of several PV-ES systems located in Finland where they are considered to participate in the frequency maintenance in terms of inertial support.