Frequency Nadir Prediction Method Based on the Two-Area Frequency Response Model

The prediction of frequency nadir is very important for the frequency security assessment of new power systems when the grid is disturbed. The current traditional system frequency response (SFR) model nadir prediction cannot solve the problem of spatiotemporal difference in frequency response, which will lead to a large error between the predicted nadir and the actual nadir, and will cause the frequency protection of the grid to operate incorrectly when the active power deficit occurs in the system. In this paper, we first analyze the two-area frequency response (TAFR) model considering the spatiotemporal features of frequency and establish a TAFR model containing wind energy, subsequently obtain the analytic solution of the model. Then, a prediction method of the frequency nadir is proposed based on the above model. Finally, simulations are performed in the detailed model, and the results show that the method can precisely characterize the spatiotemporal properties of the frequency response between regions, which verifies the accuracy and generality of the method.