The location and capacity of distributed wind generator ( DWG) and the battery energy storage ( BES) both affect the operating state of the distribution system.In order to improve the wind power accommodation capacity of the distribution system and weaken the effect of wind power output uncertainty,a coordinated optimal allocation for the locating and sizing of DWG and BES is performed in the planning stage.Then,a chance-constrained programming model,of which the objective function is to maximize the annual comprehensive income,is established by taking into consideration the stochastic power flow of the wind-storage system to reflect the operating state and the uncertainty of the distribution system containing DWG and BES.Moreover,an improved multi-population genetic algorithm is proposed,and an effective searching optimal mechanism is introduced to enhance the performance of the algorithm.Simulated results on the IEEE 33-bus distribution system show that the proposed optimization model is rational and that the proposed algorithm is effective.