A Study On Dynamic Equivalence Of Wind Farms

With the increase of wind farm penetration on power systems, the wind farms begin to have a more and more important influence on power systems. In order to analyze dynamic performance of power systems with wind farms, adequate wind farms models need to be developed. Compared to conventional power plants, large wind farms consist of a large number of generators of small size, sometimes up to several thousands. As a result, when doing dynamic simulation for a large interconnected power system, in order to reduce the complexity of power system analysis and the simulation time, equivalent wind farm models have to be developed. This paper will focus on the dynamic equivalence of fixed speed wind turbines,and the main research achievements are as follows:1. A detailed model of fixed speed wind turbine is developed, including the wind power model, drive train model, generation system model and pitch angle control model. This model has been implemented in DIgSILENT.2. In this paper, monkey algorithm is studied, which is used to solve the optimization of multivariate systems. It is improved, and then proposed to be applied to dynamic equivalence of wind farms. This algorithm is realized by DPL in DIgSILENT.3. The definition and processes of dynamic equivalence is introduced. inluding how to apply to wind farms.4. In this paper, the critical clearing time is considered to be the evaluation criteria of equivalence method, and dynamic equivalence of several different types of fixed speed wind turbines is analyzed. The critical clearing time of the equivalent system is very similar to the real system, which validates that the algorithm can be applied to dynamic equivalence of wind farms, and has high accuracy. Compared to weighted method, the method in this paper has much higher accuracy. Compared to genetic algorithm, monkey algorithm is more stable and converges faster.