Capacity optimization of energy storage system in wind farm considering battery life and reliability benefits

Generally, installing a storage system in a wind farm can improve the reliability performance of power systems. However, the capital and maintenance costs are very high. To obtain the highest benefit of storage systems, it is necessary to optimize the capacity of these systems. On basis of a storage smoothing strategy that wind farm output power is equal to the average wind generating power during a period of time, the optimization model of storage system capacity is proposed in this paper considering some effect factors, such as investment cost, battery life and reliability benefit. The service life and life cycle cost of storage battery are considered in storage system cost model. A modified IEEE-RBTS test system was used to demonstrate the effectiveness of the proposed method and models. Results of case studies show that the storage smoothing strategy with 8-hour average output is optimal for the configuration of wind farm storage system; the higher wind power penetration is, the bigger the benefits of installing storage system is; the reliability performance of basic system has a significant impact on the optimal capacity of storage system.