Method for Assessing Grid Frequency Deviation Due to Wind Power Fluctuation Based on “Time-Frequency Transformation”

Grid frequency deviation caused by wind power fluctuation has been a major concern for secure operation of a power system with integrated large-scale wind power. Many approaches have been proposed to assess this negative effect on grid frequency due to wind power fluctuation. Unfortunately, most published studies are based entirely on deterministic methodology. This paper presents a novel assessment method based on “Time-Frequency Transformation” to overcome shortcomings of existing methods. The main contribution of the paper is to propose a stochastic process “simulation” model which is a better alternative of the existing dynamic frequency deviation simulation model. In this way, the method takes the stochastic wind power fluctuation into full account so as to give a quantitative risk assessment of grid frequency deviation to grid operators, even without using any dynamic simulation tool. The case studies show that this method can be widely used in different types of wind power system analysis scenarios.