Journal ArticleDOI
Frequency estimation by demodulation of two complex signals
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TLDR
In this paper, the authors proposed a method for frequency estimation in a power system by demodulation of two complex signals, which does not introduce a double frequency component and can improve fast frequency estimation of signals with good noise properties.Abstract:
This paper presents a method for frequency estimation in a power system by demodulation of two complex signals. In power system analysis, the /spl alpha//spl beta/-transform is used to convert three phase quantities to a complex quantity where the real part is the in-phase component and the imaginary part is the quadrature component. This complex signal is demodulated with a known complex phasor rotating in opposite direction to the input. The advantage of this method is that the demodulation does not introduce a double frequency component. For signals with high signal to noise ratio, the filtering demand for the double frequency component can often limit the speed of the frequency estimator. Hence, the method can improve fast frequency estimation of signals with good noise properties. The method loses its benefits for noisy signals, where the filter design is governed by the demand to filter harmonics and white noise. The method has been previously published, but not explored to its potential. The paper presents four examples to illustrate the strengths and weaknesses of the method.read more
Citations
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Journal ArticleDOI
Power system frequency estimation using least mean square technique
TL;DR: In this article, a least mean square (LMS) algorithm in complex form is presented to estimate power system frequency where the formulated structure is very simple and the three-phase voltages are converted to a complex form for processing by the proposed algorithm.
Journal ArticleDOI
Estimation of frequency and its rate of change for applications in power systems
TL;DR: In this paper, a new method for estimation of power frequency and its rate of change is presented, which is based on a newly developed quadrature phase-locked loop concept.
Journal ArticleDOI
Adaptive Frequency Estimation in Smart Grid Applications: Exploiting Noncircularity and Widely Linear Adaptive Estimators
TL;DR: This article introduces a unified framework for the estimation of instantaneous frequency in both balanced and unbalanced conditions in a three-phase system, thus consolidating the existing approaches and providing next-generation solutions capable of joint adaptive frequency estimation and system fault identification.
Journal ArticleDOI
Measuring power system harmonics and interharmonics by an improved fast Fourier transform-based algorithm
TL;DR: In this article, an improved FFT-based algorithm to measure harmonics and interharmonics accurately is proposed, where a frequency-domain interpolation approach is adopted to determine the system fundamental frequency, and the interpolatory polynomial method is applied to reconstruct the sampled time-domain signal; it is followed by using the FFT to calculate the actual harmonic components.
Journal ArticleDOI
Widely Linear Adaptive Frequency Estimation of Unbalanced Three-Phase Power Systems
Yili Xia,Danilo P. Mandic +1 more
TL;DR: The proposed method makes use of the full second-order information within three-phase signals, thus promising enhanced and robust frequency estimation and is well matched to unbalanced system conditions and also provides unbiased frequency estimation.
References
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Journal ArticleDOI
Estimating and interpreting the instantaneous frequency of a signal. I. Fundamentals
TL;DR: The concept of instantaneous frequency (IF), its definitions, and the correspondence between the various mathematical models formulated for representation of IF are discussed in this paper, and the extent to which the IF corresponds to the intuitive expectation of reality is also considered.
Estimating and Interpreting The Instantaneous Frequency of a Signal
TL;DR: In this paper, the concept of instantaneous frequency (IF) is extended to discrete-time signals, and the specific problem of estimating the IF of frequency-modulated (FM) discrete time signals embedded in Gaussian noise is explored.
Journal ArticleDOI
A New Measurement Technique for Tracking Voltage Phasors, Local System Frequency, and Rate of Change of Frequency
TL;DR: In this paper, the frequency and rate-of-change of frequency at the bus can also be determined from the positive sequence voltage phase angle, and the theoretical basis of these computations and results of experiments performed in the AEP power system simulation laboratory are also outlined.
Journal ArticleDOI
Estimating and interpreting the instantaneous frequency of a signal. II. Algorithms and applications
TL;DR: The concept of instantaneous frequency (IF) is extended to discrete-time signals and methods based on a modeling of the signal phase as a polynomial have been introduced.
Journal ArticleDOI
Frequency tracking in power networks in the presence of harmonics
TL;DR: In this paper, a modified zero-crossing method using curve fitting of voltage samples is proposed, and polynomial fitting of the discrete Fourier transform (DFT) quasi-stationary phasor data for calculation of the rate of change of the positive sequence phase angle.
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