Sizing Energy Storage Based on a Life-Cycle Saving Dispatch Strategy to Support Frequency Stability of an Isolated System with Wind Farms

Wind power fluctuations usually cause grid frequency deviations, which could have a significant impact on an isolated power system. This paper proposes a dispatch strategy of the energy storage (ES) to support grid frequency stability of the isolated power system. The dispatch strategy of the ES is based on the forecasted mean wind speed and the corresponding standard deviation. Based on the dispatching scheme, a power spectrum density (PSD)-based method has been developed for sizing the ES and validated through system simulations based on the actual wind speed data and real isolated system in China. Results presented in this paper have shown demonstrated that the cycle-life of the ES can be significantly saved by using the proposed dispatch strategy. The developed ES sizing method has taken the random characteristics of wind power fluctuations and the frequency responses of the system into full consideration. Therefore, the proposed dispatch strategy and sizing method of the ES is general and can be applied to other isolated power systems with the ES being used to support grid frequency stability.