A Framework for Assessing the Inertia Distribution of Power Systems

In a modern power system with high penetration of renewable generation, the system inertia decreases dramatically and will show nonnegligible spatial-temporal distribution characteristics. In this paper, we propose an integrated framework for assessing and revealing the spatial-temporal distribution characteristics of the inertia, i.e., the overall inertia level at each time period and the spatial distribution of the inertia within the system. This framework incorporates two novel metrics, i.e., rate of change of inertia (RoCoI) and the improved inertia distribution index (IDI), for quantitative evaluation of the system inertia. The RoCoI index is derived from the generation scheduling tool, while the IDI is calculated based on the frequency data measured by PMUs. Case studies on the IEEE RTS-96 system demonstrate the effectiveness of the proposed approach, and indicate the time-varying as well as locational impacts of inertia distribution on the system's frequency response.