Practical Modeling of Flywheel Energy Storage for Primary Frequency Control in Power Grids

With significant integration of renewable energy sources (RES), particularly wind power, there is a need for fast regulation to counteract the effect of frequency variation through primary frequency control (PFC). Flywheel energy storage (FES) technologies are particularly important, because of their fast response capability and high flexibility of operation. However, not much work has been carried out on properly modeling the FES to analyze its performance at the power system level. Therefore, the focus of this paper is on developing a dynamic model for frequency regulation studies, practical and useful for system operators, of a FES system connected to a power system to provide PFC, and study its effects on system stability. The proposed practical model is tested using a commercial simulation package, and compared with respect to a previously reported test system equipped with a high-capacity wind generator, which creates significant frequency and voltage fluctuations, demonstrating its application for solving PFC problems in power networks.