More benefits can be earned for wind farms integrated with a battery energy storage system (BESS) by improving the acceptance of wind power. Firstly

this paper proposes a double optimization model for battery energy storage system considering grid structure. The optimal configuration node

power

capacity of BESS are determined with the aim of incremental benefits maximization for wind and storage joint system compared with wind farms only considering system security constraints in the outer planning model. The benefits maximization of wind and storage joint system is chosen as the objective function

and the output of generating units

wind farm

BESS as decision variables. In the constraints

power balance

spinning reserve

power and capacity of BESS are considered in the inner optimization model. A numerical optimization algorithm

which is based on an improved empirical competition algorithm is proposed to calculate the model. Finally

the validity of this model is verified in an improved IEEE 118-node system. Case results suggest that the best configuration of BESS can increase wind farm benefits

meanwhile both benefits increments and the improvement of abandoned wind show an increasing trend with reduction in investments or the increase in grid price. Furthermore

an appropriate initial capacity of BESS is able to improve the benefits of composite BESS and wind generation system. And on the premise of guaranteed convergence

the improved empirical competition algorithm can effectively increase the computing speed compared with the traditional one. This work is supported by National Basic Research Program of China (973 Program) (No. 2014CB23903) and National Natural Science Foundation of China (No. 51337005).