Renewable Energy Power System Unit Commitment Considering Regional Frequency Stability Requirement

With the development of new power systems, the formation of a “double high” pattern in frequency has made frequency security a prominent problem. It is particularly important to formulate a unit power generation plan with frequency security constraints at the day-ahead scale. However, a unit commitment model with frequency security constraints based on a unified frequency for the entire network cannot be used because the frequency exhibits spatial variations. This problem is solved in this study by establishing a single-machine aggregation model for the frequency response of a partitioned power system. In the unit commitment model, the frequency support between individual regions is established based on the distribution of the disturbance power over individual subregions. The index of the initial frequency change rate is introduced for each subregion to establish an analytical expression for the relationship between the frequency security constraints and the unit commitment scheme. Finally, the effectiveness of the model and the solution algorithm is verified for the improved IEEE39 node system.