On some spectrum estimation methods for analysis of non-stationary signals in power systems. Pt. 1. Theoretical Aspects. & Pt. 2. Numerical Applications
Bracale, A ; Carpinelli, G ; Lauria, D ; Leonowicz, Z ; Lobos, T ; Rezmer, J
/ ||RZ I07/04/I-045 ||RZ I07/04/I-046 ||ENY-ARTICLE-2008-012|
Abstract: Part I Frequency power converters and arc furnaces generate a wide spectrum of harmonic components and interharmonics. Representation of signals in time and frequency domain has been of interest in signal processing areas for many years, especially taking in the limelight time-varying non-stationary signals. Standard tools of harmonic analysis based on the Fourier transform assume that only harmonics are present and the periodicity intervals are fixed, while periodicity intervals in the presence of interharmonics are variable and very long. In this paper the Prony method was tested for this purpose and a novel approach for the analysis of power nonstationary signals, based on the “subspace” methods, is proposed: the “rootMusic” harmonic retrieval method which is an example of highresolution eigenstructure-based methods. Both methods can allow an accurate and useful estimation of power quality indices as well as of the interharmonic frequencies with their changes in time. This paper, which reports the theoretical aspects of these methods, is a companion paper to a paper of the same title, Part II, in which the numerical aspects of the proposed spectrum estimation methods are analysed using non-stationary voltage and current waveforms in a supply system of a dc arc furnace. Part II This is a companion paper to a paper of the same title, Part I, in which the theoretical aspects of some spectrum estimation methods for analysis of non-stationary voltages and currents in power systems with nonlinear loads are analysed. In particular, the Prony model and rootMusic method are taken into account. In this paper, numerical applications of the methods presented in Part I are discussed, in order to illustrate their implementation problems and practical applications. To investigate the methods, several experiments were performed using non-stationary voltage and current waveforms in a supply system of a dc arc furnace. For comparison, similar experiments were repeated using the Short-Time Fourier Transform. The comparison proved the effectiveness of the new methods; however, their computational efforts can be much more complex. Conclusions and recommendations are made concerning the framework of each method.
Keyword(s): Fourier Transform ; Waveform Distortion Analysis ; Power System ; Subspace Methods ; Prony Method
Note: 11th International Conference on Harmonics and Quality of Power. ICHQP. Lake Placid, New York, September 12-15, 2004. Piscataway, NJ: IEEE 2004, ref. 60 & 61, 7 + 6 p.
Fulltext : http://zet10.ipee.pwr.wroc.pl/record/14/files/
Cited by: try citation search for ENY-ARTICLE-2008-012; RZ I07/04/I-045; RZ I07/04/I-046
Record created 2008-03-06, last modified 2008-03-18
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