Control and sizing methodology of BESS in wind farms considering adaptive adjustment of SOC

Battery energy storage system (BESS) has been used to smooth the wind power fluctuations. However, because of the cost of BESS is relatively high, the effectiveness of fluctuation smoothing has been limited. Meanwhile, capacity optimization of energy storage can reconcile the relationship between energy storage cost and the smoothing effectiveness. Thus, a novel sizing algorithm of BESS is proposed to optimize the capacity of BESS. Firstly, state-of-charge (SOC) of energy storage system is used as index to avoid over-charge/-discharge of energy storage system to prolong the lifespan of BESS. Secondly, an objective function is presented to minimize the overall cost including the invest cost, operation cost and punishment cost to determine the optimal BESS capacity. At last, improved partial swarm optimization algorithm is adopted to deal with this problem. The calculation results prove the proposed algorithm is good.