Frequency Nadir Solution of the Power System Considering Disturbance Probability Characteristics

With the increasing proportion of new energy sources, the power system has undergone various changes in terms of sources, grids, loads, and storage, making the dynamic process of system frequency more complex. It is necessary to study it from the perspective of the new situation. First, the uncertainty of disturbances is analyzed. By using high-order Gaussian fitting to analyze the differences between power generation and consumption, the probabilistic characteristics of disturbances are extracted, and the uncertainty is modeled with the characteristics of disturbances. Subsequently, the frequency response model of the power system is simplified and analyzed, resulting in an analytical formula related to the frequency nadir of the power system. Therefore, the probability of the frequency nadir is obtained from the probability of disturbances. Finally, a probability density transformation method is used to convert the probability density of disturbances into the probability density of the frequency nadir, completing the frequency nadir solution of the power system considering disturbance probability characteristics. The comparison between the simulation method and this method shows that it significantly improves computational efficiency while maintaining a minor error in results, providing effective data for the safety operation and backup planning of the power system.