Simulation of power fluctuation of wind farms based on frequency domain. Part two. Transformation algorithm and model simplification

The wind power fluctuation model built up in the frequency domain is mathematically equivalent with that in the time domain, and has a clearer physical meaning therefore describes the fluctuation more accurately. However, the simulation of this model is required to deal with the time-frequency transformation related to the power spectrum density (PSD), which is more special and complicated than normal transformations. Meanwhile, the computational complexity also increases significantly, more computation resources are needed. These problems negatively affect the engineering application of the model. To overcome these disadvantages, the physical meaning of PSD based on fundamental concepts is presented, so that the specialties of this model compared with conventional ones can be understood. Then the time-frequency transformation algorithm is derived, which is fast to be implemented in digital computers. Two model simplification approaches are proposed subsequently, both of which can tremendously accelerate the simulation for either embedded integration or concentrated integration scenarios. The numerical simulation results finally validate the feasibility and efficiency of this model. © 2011 State Grid Electric Power Research Institute Press.