Frequency estimation in three-phase power systems with harmonic contamination: A multistage quaternion Kalman filtering approach

TL;DR

This paper introduces a multistage quaternion Kalman filtering method for accurately estimating the fundamental frequency and its rate of change in three-phase power systems, even with harmonic contamination.

Contribution

A novel two-stage quaternion Kalman filtering approach that jointly models three-phase voltages and accounts for harmonic contamination in frequency estimation.

Findings

Effective frequency estimation demonstrated on synthetic data.

Robustness to harmonic contamination validated with real-world data.

Improved accuracy over existing methods.

Abstract

Motivated by the need for accurate frequency information, a novel algorithm for estimating the fundamental frequency and its rate of change in three-phase power systems is developed. This is achieved through two stages of Kalman filtering. In the first stage a quaternion extended Kalman filter, which provides a unified framework for joint modeling of voltage measurements from all the phases, is used to estimate the instantaneous phase increment of the three-phase voltages. The phase increment estimates are then used as observations of the extended Kalman filter in the second stage that accounts for the dynamic behavior of the system frequency and simultaneously estimates the fundamental frequency and its rate of change. The framework is then extended to account for the presence of harmonics. Finally, the concept is validated through simulation on both synthetic and real-world data.