Quantification Method for Inertia Heterogeneity of Power System Considering Node Coupling

Usually, the equivalent inertia constant is used to characterize the inertia level of the power system. However, as thermal power units with high inertia are replaced by renewable energy units with low inertia, the overall inertia level of power system gradually decreases. In addition, due to the cluster distribution of renewable energy units, inertia has obvious uneven distribution in space. Such centralized parameters as the system equivalent inertia constant cannot highlight the low inertia characteristics of the local area, which will bring security risks to power system. To this end, a method to quantify the spatial distribution of power system inertia considering nodal coupling is proposed. The nodal inertia is defined and calculated according to the frequency coupling between nodes based on the equivalent inertia of power system as the reference value. Finally, the proposed method is analyzed in the IEEE 10 machine 39 node system for arithmetic examples.