Rotor Speed-Free Estimation of the Frequency of the Center of Inertia

This letter proposes a formula to estimate the frequency of the center of inertia based exclusively on measures of bus frequencies, obtained, for example, from phasor measurement units, the network admittance matrix, and two parameters of synchronous generators, namely, the inertia constant and the internal reactance. The proposed formula can be utilized online and requires a highly reduced set of measures of bus frequencies. The letter discusses the theoretical background of the proposed expression and tests it with a 1479-bus model of the all-island Irish transmission system.