Research On The Equivalent Modeling Of Large Wind Farms

The wind energy is regarded as a potential new energy. As a result, the utilization of wind energy has been paid more and more attention to. The main form of the use of wind energy is adopting wind turbine to generate electricity. More and more wind tur-bine generating sets has been connected to the gird. The output power of the wind farm is heavily influenced by the speed of the wind. So the stability of the gird face great challenge because of the injecting of wind power. In order to know how the wind farm will influence the gird, we need to know the equivalent model of the wind farm first.The research status of the wind farm model is described first. The advantage and disadvantage of the present research is discussed. On the basis of that, the two most important questions are pointed out. The first one is the model structure of the wind farm; the second one is how to decide the value of the parameters in the model. The new method is proposed in the process of handling that two questions.The aggregated model is most widely used model of the wind farm. This model is based on the model of the signal wind turbine generator set, which include the input wind speed model, the wind turbine model, the transmission system model and the generator model. Two kinds of generator model are introduced in this paper. One is the model of the squirrel cage induction generator, the other one is the model of the doubly fed induction generator model. This two kind of generators is most widely used in the wind farm.The traditional aggregated model of the wind farm which is commonly used is detailed introduced. The disadvantage of that model is pointed out. After that, the model of the wind farm used in this paper is proposed which is modified from the tra-ditional aggregated model. The model consist of three subsystem:the model of the equivalent wind, the model of the collection system of the wind farm and the model of the wind turbine generating set.The value of parameter of the wind farm model has a great influence on the out-put power of the wind farm. In order to improve the accuracy of the model, the opera-tion data of the wind farm is used to identify the value of the parameter of the new model. The identification strategy of the three subsystem is detailed introduced re-spectively.One squirrel cage induction wind farm and one doubly fed induction wind farm are chosen to prove the accuracy of the theory proposed in this paper. The detailed model, the traditional aggregated mode and the model proposed in this paper of that two wind farm are built on the MATLAB/Simulink platform. The simulation result shows the effectiveness of the identified model.