PMU-based Estimation of the Frequency of the Center of Inertia and Generator Rotor Speeds

The paper compares a variety of on-line approaches based on PMUs to estimate the angular speed of individual synchronous machines as well as of the center of inertia. These approaches involve the solution of an optimization problem or a Weighted Least Square problem and are based on the frequency divider formula that has been recently proposed on the Transactions on Power Systems by the second and third authors. The case study is based on a dynamic 1,479-bus model of the all-island Irish system with inclusion of stochastic wind speed, noise and time-varying PMU measurement delays. The scenarios studied in the paper allow identifying the key features of the considered estimation approaches. A thorough discussion on the impact of measurement delays and system size is also provided.