Stochastic Optimization Method Of Multi Wind Power Grid Dynamic Economic Dispatch

Large-scale wind farms connected to the grid has brought a huge challenge for power system economic dispatching. In order to study the output characteristics of wind farm, copula theory is introduced to construct the model of joint distribution for the output power of multiwind farms which can depict correlation caused by geographical and weather similarity well.Then, a scenario generation method based on the correlation of wind farm is proposed, and a dynamic economic dispatch model considering the correlation of wind farm is proposed, so as to verify the effect of wind power correlation on scheduling.In order to improve the solving speed of the dynamic economic dispatch of the actual large power grid with multi wind farms, and give a accurate depication of the randomness and the relative characteristics of the wind farm,a stochastic optimization model of the 24 point dynamic economic dispatch is established, which takes the goal to minimize the total fuel consumption, the pollution gas emission fee and the purchase cost. In order to deal with the stochastic of wind output power and the coupling of operation constraint among different times, two-stage compensation algorithm is applied to solving this model. The compensation variables are defined for constraints with random variables, and the original dispatching model is then transformed into two-stage model. The first-stage model is of constraints about conventional variables, and expected compensation value calculated by numerical integrating of random variable is added to the objective function. The second-stage model is constrained by random variables, and its objective function is to minimize the expected compensation value based on Copula probability distribution. The optimal solution is obtained by the alternating iteration of the two-stage model.The example results of IEEE 118 bus system and an actual provincial grid show that considering wind farm output power correlation can give a result which conform to actual situation when solve the dispatching problem with multi-wind farm.second phase compensation algorithm can quantity the impact of power system security and economy caused by wind power and given the minimum value of compensation fees,, so as to provide a reliable basis for decision making for scheduling person. At the same time, the algorithm has the advantages of little scale and high solving speed calculation. This shows the effectiveness and usability of the proposed stochastic optimization method.