Evaluating Regional Inertia-based COI with Synchrophasor Measurement

Due to the replaced number of large synchronous generators and renewable penetration, the center of inertia (COI) becomes a key factor in wide-area control with stability analysis. Knowing the area-based COI frequency significantly introduces the inertia estimation latency regarding periodic time-varying. This work proposes a pseudo technique based on measured angles of phasor measurement units (PMUs) to determine the area-based COI frequency, thus improving the precision of inertia estimation of the real-world power system. At the beginning, a two-machine model strategy is presented by considering ambient signals from potential PMU locations/buses while dividing the area estimation into a separate quantity of two significant areas (i.e., western and eastern regions) regarding the longitudinal 60 Hz Japan transmission network. Then, the pseudo phasor observation points considering different locations in both areas are established to determine the COI frequency for each area. The resulting accuracy is verified by comparing to the ratio of known/contributing synchronous power outputs. Finally, the estimated inertia-based COI frequencies in both areas are combined to identify the total system inertia in comparison with the conventional inertia estimation-based disturbance technique.