Method for Exact Compensation of Voltage and Current Phasors Computed by Orthogonal Finite Impulse Response Filters During Frequency Variations
Abstract:This article presents a generic method that fully compensates for the errors introduced by orthogonal finite impulse response filters (full-cycle discrete Fourier transform, half-cycle discrete Fourier transform, Cosine filter) in phasor computation during frequency variations in power systems. To accomplish this, the proposed method uses an accurate and easily calculated estimate of the local instantaneous frequency. The method is robust and precise and can be extended to deal satisfactorily with the effect of harmonics. Also, its implementation simplicity makes it attractive for real-time applications. Simulation results are provided to demonstrate the effectiveness of the proposed method.
Keywords: discrete Fourier transform; frequency variations; instantaneous frequency estimation; orthogonal finite impulse response filters; phasor computation; power system measurements; protective relaying
Document Type: Research Article
Affiliations: Electrical and Computer Engineering Department, National Technical University of Athens, Athens, Greece
Publication date: 2011-04-01