Evaluation of the Modified Covariance Method Performance with Cleaning Characteristic Harmonic Digital Filter in Protection Relay

Abstract

Under harsh transient situations, contemporary protection relays necessitate the accurate and swift estimation of phasors. The prior CCHDF filter was limited by DFT techniques and utilized the Biunivocal Frequency Relationship of Phasors (BFRP). The Modified Covariance Method (MCM) is a sophisticated autoregressive spectral estimator offered as a substitute for spectral estimation in this study. This method improves the estimation of frequency, magnitude, and phase in challenging conditions. The initial algorithm's structure is preserved by the resulting MC-CCHDF (Modified Covariance CCHDF) filter, which provides enhanced accuracy and a faster convergence rate with harmonics and noise that are closely spaced.