A quaternion frequency estimator for three-phase power systems

Motivated by the need for accurate frequency estimation in power systems, a novel algorithm for estimating the fundamental frequency of both balanced and unbalanced three-phase power systems, which is robust to noise and distortions, is developed. This is achieved through the use of quaternions in order to provide a unified framework for joint modeling of voltage measurements from all the phases of a three-phase system. Next, the recently introduced Hℝ-calculus is employed to derive a state space estimator based on the quaternion extended Kalman filter (QEKF). The proposed algorithm is validated over a variety of case studies using both synthetic and real-world data.