Investigation on Statistical Sizing Schemes for Hybrid Energy Storage Systems

This paper explores the power and capacity planning problems in hybrid energy storage systems (HESS) used in grid-connected solar/wind power systems using statistical analysis and numerical methods. A proper HESS operation and power management system allows for real-time power distribution control with the required system dynamic response and the characteristics of the internal energy storage devices. The goal of instantaneous power allocation of HESS is to effectively manage the state of charge (SOC), power level, and operating conditions of its internal energy storage devices to achieve optimal efficiency and capacity optimisation. The HESS power and capacity planning method discussed in this paper can be used in most HESS planning cases on a given set of system operating conditions. In order to present the feasibility of the proposed method, the HESS application case discussed in this paper aims to smooth the power fluctuation of wind and solar power generations and simultaneously ensure the specified dispatching power level and quality. In this paper, HESS cases analysis and numerical comparison studies are carried out with a typical solar/wind power generation system corresponding to two different power dispatching levels.