Estimation of Center of Inertia and Center of Powerfrom WAMS and SCADA Measurements

The increasing share of distributed renewable generation is reshaping the dynamics of modern power systems, necessitating more accurate and adaptive monitoring solutions. Wide Area Monitoring Systems (WAMS), based on Phasor Measurement Units (PMUs), provide high-resolution systemwide observability, enabling advanced applications. A critical input to these functions is the system frequency, which is often taken to be equal to the frequency of Center of Inertia (COI), in which the exact estimation remains an open question due to varying definitions of inertia-based weighting. This paper investigates alternative formulations using inertia constants and kinetic energy terms to determine the most representative system frequency. To support the evaluation, the spatial behavior of the Center of Power (COP) is also analyzed using SCADA-based power flow data. Results derived from real PMU and SCADA measurements show that the H·S-based COI formulation better aligns with the actual measured COP behavior.