Frequency Response Model and Its Application for the Renewable Energy Resources Power Plant

Renewable energy resources (RESs) are usually connected to the power plant through power electronic converters which cannot provide inertia to the power plant like synchronous machines. Therefore, the power plant's frequency dynamic response performance may be unsatisfactory when power fluctuations occur. In order to evaluate the influence of RESs output fluctuation and load power fluctuation on the frequency of the RESs power plant, this paper establishes a frequency response model. Then, the model is discretized and its corresponding matrix form expression is derived. Consequently, based on the proposed frequency response model, this paper establishes the frequency security constraints, which is combined into the economic dispatching problem of the RESs power plant. The accuracy of the proposed frequency dynamic model is verified by case studies. The case studies also show that the economic dispatching model is conducive to simultaneously improving the safety and economy of the RESs power plant.