Energy storage system(ESS)participation in day-ahead scheduling of the active distribution network(ADN)is of great significance for its improvement of utilization efficiency of distributed generation(DG)and operating economy in distribution networks. A new operating optimization model is proposed for battery energy storage system(BESS)in an active distribution network with DG. Both time-of-use price and the price difference between sale and purchase are considered to realize cost minimization of ADN. It has improved the accommodation capability of DG and minimized the cost of purchasing electricity from the main grid. In order to improve the operation economy

the equivalent operating cost of BESS is considered according to calculation of the cyclic life of BESS. The branch and bound-interior point method is used to consider discrete variables and inter-temporal constraints so as to decompose the problem into a series of static active power optimization problems with only continuous variables. Numerical tests via the modified IEEE 33-bus system with DG and BESS show that the proposed model and method are effective and feasible. This work is supported by National Natural Science Foundation of China(No. 51577049).