Least Squares Based Renewable Energy-Enrich Regional Inertia Evaluation Method for Interconnected Power Systems

With the rapid increase of the penetration of renewable energy sources in the power system, the inertia level of the power system continues to go down, and the frequency regulation capability is gradually weakened. In addition, the uneven distribution of renewable energy-enriched areas and synchronous power-enriched areas makes the spatial distribution characteristics of inertia more prominent, which seriously threatens the interconnected system frequency stability. Aiming at the above problems, a renewable energy-enriched area inertia assessment method based on the least squares method is proposed. First, the mechanism of regional inertia on the frequency response of the power system is explained. Secondly, the inertia response characteristics of renewable energy units under different control modes are analyzed and treated as controlled current-sources and voltage-sources respectively. Further considering the parameter privacy of renewable energy units, the least squares-based method is adopted to identify the regional inertia; finally, the improved the IEEE-39 bus test system constructed in MATLAB/Simulink simulation software is used to verify the proposed method. The simulation results show that the method is accurate and applicable to the estimation of equivalent inertia of renewable energy power systems under different scenarios.