Robust Planning of Source-grid-storage System Considering Frequency Security Based on Improved N−k Uncertainty Set

With the increasing integration of renewable energy sources into the grid, frequency security issues in power systems have become increasingly prominent. In this paper, we incorporate frequency security requirements into the planning process by constructing an improved N-k uncertainty set that considers both unit capacity and unit failure probabilities, along with a wind power load scenario set that retains extreme data. A frequency response model for a thermal-wind-storage system is developed, and security constraints related to frequency that satisfies a certain confidence level are derived. Additionally, a robust optimization planning model for source-grid-storage systems is developed, which accounts for frequency safety chance constraints. The original problem is reformulated into a master-subproblem, which is iteratively solved using the column-and-constraint generation method (CCG). Finally, the effectiveness of the proposed model is validated through case analysis.