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Time-frequency and time-scale analysis of Barkhausen noise signals

Padovese, Linilson Rodrigues; MARTIN, N.; MILLIOZ, F.
Fonte: PROFESSIONAL ENGINEERING PUBLISHING LTD Publicador: PROFESSIONAL ENGINEERING PUBLISHING LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
771.6482%
Carrying out information about the microstructure and stress behaviour of ferromagnetic steels, magnetic Barkhausen noise (MBN) has been used as a basis for effective non-destructive testing methods, opening new areas in industrial applications. One of the factors that determines the quality and reliability of the MBN analysis is the way information is extracted from the signal. Commonly, simple scalar parameters are used to characterize the information content, such as amplitude maxima and signal root mean square. This paper presents a new approach based on the time-frequency analysis. The experimental test case relates the use of MBN signals to characterize hardness gradients in a AISI4140 steel. To that purpose different time-frequency (TFR) and time-scale (TSR) representations such as the spectrogram, the Wigner-Ville distribution, the Capongram, the ARgram obtained from an AutoRegressive model, the scalogram, and the Mellingram obtained from a Mellin transform are assessed. It is shown that, due to nonstationary characteristics of the MBN, TFRs can provide a rich and new panorama of these signals. Extraction techniques of some time-frequency parameters are used to allow a diagnostic process. Comparison with results obtained by the classical method highlights the improvement on the diagnosis provided by the method proposed.; FAPESP[05/51100-9]; FAPESP[06/04935-0]

Estudo do número de Strouhal em função do número de Reynolds em um anteparo triangular utilizando a técnica da análise tempo-freqüência; Study of the number of Strouhal in function of the Reynolds number in a triangular bluff body using the technique of the analysis time-frequency

Pinhata, Gustavo Marcelo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/08/2006 PT
Relevância na Pesquisa
767.5416%
Neste trabalho simulou-se o escoamento do fluxo de ar em um tubo, com um anteparo de formato triangular com arestas cortantes, posicionado no centro do tubo. O objetivo do estudo é a análise do comportamento do número de Strouhal em função do número de Reynolds. Para isto, foi utilizada a técnica da análise tempo-freqüência, baseada na transformada de Fourier e na transformada de Gabor. Os ensaios foram realizados com o fluxo com velocidades médias de escoamento de 3 a 10 m/s, sendo utilizado um sensor de pressão tipo piezo-resistivo para a detecção da flutuação de pressão ocasionada pelo desprendimento e formação dos vórtices. Os ensaios foram realizados em cinco etapas com o objetivo de se verificar a influência dos seguintes parâmetros na coleta de sinais e no fenômeno: ruído da rede elétrica; influência do anteparo e do ruído proveniente do escoamento do fluxo de ar; número de pontos da amostragem na coleta dos dados; do comprimento da tubulação; e posicionamento do sensor. Pode-se observar, a sensibilidade do sistema de medição através do ensaio realizado sem o anteparo, sendo verificada a influência do ruído do escoamento de ar pelo tubo; pode-se observar também uma pequena interferência do ruído da rede elétrica predominantemente para velocidades abaixo de 3 m/s. Apesar das influências citadas...

Análise tempo-freqüência de um escoamento em tê: desenvolvimento de uma técnica de comparação entre dados experimentais e resultados numéricos obtidos com os modelos LES e DES; Time-frequency analysis of the flow in a tee junction: comparing experimental data with numerical results from LES and DES models

Tiago, Graziela Marchi
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 30/03/2007 PT
Relevância na Pesquisa
968.7662%
Escoamentos turbulentos têm sido por muitos anos o objetivo de importantes estudos para descobrir sua dinâmica. Dentre as características mais significativas, destaca-se a multiplicidade de escalas que os caracterizam, desde as maiores estruturas (baixas freqüências) controladas pela geometria que as geram, até as menores estruturas (altas freqüências) limitadas pela viscosidade do fluido. Uma idéia importante é o conceito de vórtices que está ligado a melhorias nas técnicas de visualização, tanto em laboratório quanto em experimentos numéricos. Estes vórtices têm um importante papel em numerosas aplicações tecnológicas, sendo necessário entender a dinâmica da organização de seus movimentos para controlar mecanicamente sua produção ou supressão. Neste contexto, a análise de um misturador de ar em um escoamento em tê é o principal objetivo de estudo deste trabalho. A geometria em tê é bastante simples, mas propicia o aparecimento de um escoamento com passagem de vórtices. Testes experimentais do escoamento, com duas entradas de ar com temperaturas diferentes, foram realizados no Laboratório de Engenharia Térmica e Fluidos da Escola de Engenharia de São Carlos da Universidade de São Paulo (LETeF - EESC - USP). As medidas de temperatura foram obtidas com termopares instalados ao longo da tubulação. Com o software CFX foram realizados estudos com métodos numéricos LES e DES aplicados ao escoamento. Estes resultados computacionais foram comparados com os dados experimentais...

Análise tempo-frequência de ondas acústicas em escoamentos monofásicos; Time-frequency analysis of acoustic waves in single-phase flow

Lima, Simone Rodrigues
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/12/2010 PT
Relevância na Pesquisa
974.963%
A presente dissertação tem como objetivo principal estudar a propagação acústica em escoamentos monofásicos. Para tal, são analisados sinais transientes de pressão fornecidos por sensores instalados em posições conhecidas na linha de teste, através do estudo de técnicas de análise de sinais, a fim de investigar se as variações do conteúdo espectral dos sinais são influenciadas pela ocorrência de vazamentos no duto. A análise dos sinais foi realizada nos planos temporal, frequencial, tempo-frequência e estatístico. Os resultados experimentais foram obtidos no oleoduto piloto do NETeF - Núcleo de Engenharia Térmica e Fluidos da USP - Universidade de São Paulo, com uma seção de testes com 1500 metros e diâmetro de 51,2 mm, com escoamento monofásico de água. Os resultados obtidos através da análise tempo-frequência mostraram-se satisfatórios, sendo esta técnica capaz de identificar a composição espectral instantânea de um sinal, ou seja, foi eficiente na identificação de picos de amplitude da frequência ao longo do eixo temporal. Além disso, a análise probabilística, através do desvio-padrão do sinal também mostrou-se eficiente exibindo uma disparidade significativa entre os sinais com e sem vazamento.; The present dissertation reports on the study of the acoustic propagation in single-phase flow. It analyzes the transient signals provided by pressure sensors in known locations in the test line through the study of signal analysis techniques to investigate if the variations in spectral content of the signals are influenced by the occurrence of leaks in the pipe. The analysis of signals was performed in the time...

Proposta e avaliação de técnicas para compressão de transitórios rápidos e análise tempo-frequência de distúrbios em redes elétricas AC; Proposal and evaluation of techniques for fast transient data compression and time-frequency analysis of AC power line disturbances

Soares, Leonardo Bandeira
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
971.9321%
Este trabalho trata de conceitos relacionados à qualidade da Energia Elétrica (EE) e, neste contexto, apresenta a proposta de técnicas para a compressão da representação de transitórios rápidos e da análise tempo-frequência de distúrbios elétricos em geral. A qualidade da Energia Elétrica é medida pelo coeficiente de desvios que os sinais de tensão e corrente apresentam em relação ao sinal senoidal ideal. Tais desvios são denominados de distúrbios, podendo ser classificados como quase estacionários (e.g. distorção de harmônicas) e eventos (e.g. transitórios rápidos). No contexto de EE, os transitórios rápidos possuem pequena duração (i.e. na ordem dos microssegundos), são detectados por altas taxas de amostragem (i.e. na ordem dos MHz) e possuem difícil parametrização. Portanto, as representações das formas de onda geralmente são armazenadas para auxiliar a avaliação subjetiva dos transitórios e dos parâmetros de interesse. Consequentemente, a compressão destas formas de onda torna-se de extrema importância para armazenar dados adquiridos por longos períodos de tempo, e estes modos de compressão são tratados nesta dissertação. Em virtude das altas taxas de amostragem utilizadas, uma técnica baseada em Análise de Componentes Principais (PCA – Principal Component Analysis) é proposta para esta representação mais compacta de transitórios. Resultados mostram que o desempenho em compressão versus qualidade de reconstrução é semelhante ao de trabalhos relacionados com a vantagem de atender aos requisitos de altas taxas de amostragem. A análise tempo-frequência é um mecanismo que auxilia na classificação e caracterização dos distúrbios elétricos. Neste trabalho...

Using cross-wavelets to decompose the time-frequency relation between oil and the macroeconomy

Conraria, Luís Aguiar; Soares, M. J.
Fonte: Universidade do Minho. Núcleo de Investigação em Políticas Económicas Publicador: Universidade do Minho. Núcleo de Investigação em Políticas Económicas
Tipo: Trabalho em Andamento
Publicado em 03/10/2007 ENG
Relevância na Pesquisa
765.5452%
A large body of empirical literature has suggested that oil price shocks have an important effect on economic activity. But in most of the literature the analysis is exclusively done in the time domain. However, interesting relations exist at different frequencies. We use (cross) wavelet analysis to uncover some of these relations, estimating the spectral characteristics of the time-series as a function of time. Our analysis suggests that the volatility of both the inflation rate and the output growth rate started to decrease in the decades of 1950 and 1960, suggesting that the great moderation started then,but that it was temporarily interrupted due to the oils crisis of the 1970s, whose effects extend until the mid 1980s. We also show that while at business cycle frequencies oil prices lead industrial production, in the very long run production increases lead oil price increases. The exception to this long-run relation occurred between the mid 1970s and mid 1980s. Our analysis also suggests that monetary policy became much more eficient after 1980 to deal with the inflationary pressures of oil shocks.; Luís Aguiar-Conraria acknowledges financial support from Fundação para a Ciência e a Tecnologia, project “Oil shocks and the Macroeconomy: Econometric estimation...

Using wavelets to decompose time-frequency economic relations

Conraria, Luís Aguiar; Soares, M. J.; Azevedo, Nuno
Fonte: Universidade do Minho. Núcleo de Investigação em Políticas Económicas Publicador: Universidade do Minho. Núcleo de Investigação em Políticas Económicas
Tipo: Trabalho em Andamento
Publicado em 10/10/2007 ENG
Relevância na Pesquisa
772.268%
Economic agents simultaneously operate at different horizons. Many economic processes are the result of the actions of several agents with different term objectives. Therefore, economic time-series is a combination of components operating on different frequencies. Several questions about the data are connected to the understanding of the time-series behavior at different frequencies. While Fourier analysis is not appropriate to study the cyclical nature of economic time-series, because these are rarely stationary, wavelet analysis performs the estimation of the spectral characteristics of a time-series as a function of time. In spite of all its advantages, wavelets are hardly ever used in economics. The purpose of this paper is to show that cross wavelet analysis can be used to directly study the interactions different time-series in the time-frequency domain. We use wavelets to analyze the impact of interest rate price changes on some macroeconomic variables: Industrial Production, Inflation and the monetary aggregates M1 and M2. Specifically, three tools are utilized: the wavelet power spectrum, wavelet coherency and wavelet phase-difference. These instruments illustrate how the use of wavelets may help to unravel economic time-frequency relations that would otherwise remain hidden.

Time-frequency analysis of intermittent two-phase flows in horizontal piping

Klein,F. L.; Seleghim Junior,P.; Hervieu,E.
Fonte: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM Publicador: Associação Brasileira de Engenharia e Ciências Mecânicas - ABCM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2004 EN
Relevância na Pesquisa
867.9306%
One of the main features associated to multiphase flows is the existence of characteristic dynamic structures according to which the different phases of a mixture of immiscible fluids can flow. The manifestation of one of these structures, known as flow pattern or regime, is determined by the flow rates as well as by physical and geometrical properties of the fluids and piping. The development of flow pattern characterization and diagnostic methods, and the associated transitions in between, is of crucial importance for an efficient engineering of such phenomena. Time-frequency analysis is used in this work to characterize horizontal air-water intermittent flow regimes. More specifically, our main objective is to reveal the existence of sub-regimes inside the intermittent regimes region with the help of the corresponding time-frequency covariance, which is capable of detecting transitions by assessing the unstationarity associated with the corresponding transitions. Experimental tests were conducted at the TALC facility at CEA-Grenoble and an extensive database was obtained, covering several types of intermittent flow. A conductivity probe, consisting in two ring electrodes flush mounted to the pipe, delivered signals from which the time-frequency covariance was calculated from the corresponding Gabor transform.

Signal-Dependent Time-Frequency Analysis using a Radially Gaussian Kernel

Baraniuk, Richard G.; Jones, Douglas L.; Baraniuk, Richard G.; Jones, Douglas L.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
874.5114%
Journal Paper; Time-frequency distributions are two-dimensional functions that indicate the time-varying frequency content of one-dimensional signals. Each bilinear time-frequency distribution corresponds to a kernel function that controls its cross-component suppression properties. Current distributions rely on fixed kernels, which limit the class of signals for which a given distribution performs well. In this paper, we propose a signal-dependent kernel that changes shape for each signal to offer improved time-frequency representation for a large class of signals. The kernel design procedure is based on quantitative optimization criteria and two-dimensional functions that are Gaussian along radial profiles. We develop an efficient scheme based on Newtonâ s algorithm for finding the optimal kernel; the cost of computing the signal-dependent time-frequency distribution is close to that of fixed-kernel methods. Examples using both synthetic and real-world multi-component signals demonstrate the effectiveness of the signal-dependent approach â even in the presence of substantial additive noise. An attractive feature of this technique is the ease with which application-specific knowledge can be incorporated into the kernel design procedure.

Beyond Time Frequency Analysis: Energy Densities in One and Many Dimensions

Baraniuk, Richard G.; Baraniuk, Richard G.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
863.259%
Journal Paper; Given a unitary operator A representing a physical quantity of interest, we employ concepts from group representation theory to define two natural signal energy densities for A. The first is invariant to A and proves useful when the effect of A is to be ignored; the second is covariant to A and measures the "A" content of signals. The construction is quite general and is also easily extended to the multi-operator case, which generalizes previously derived joint densities such as the time-frequency and time-scale distributions

Optimal Phase Kernels for Time-Frequency Analysis

Baraniuk, Richard G.; Wisur-Olsen, Fridtjof; Baraniuk, Richard G.; Wisur-Olsen, Fridtjof
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Report; Text; Text
ENG
Relevância na Pesquisa
975.2306%
Tech Report; We consider the design of kernels for time-frequency distributions through the phase, rather than amplitude, response. While phase kernels do not attenuate troublesome cross-components, they can translate them in the time-frequency plane. In contrast to previous work on phase kernels that concentrated on placing the cross-components on top of the auto-components, we set up a "don't care" region and place the cross-components there. The close connections between optimal allpass kernels and optimal lowpass kernels provide new insight into signal-dependent time-frequency analysis.

Opitmal Phase Kernels for Time-Frequency Analysis

Wisur-Olsen, Fridtjof; Baraniuk, Richard G.; Wisur-Olsen, Fridtjof; Baraniuk, Richard G.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Conference paper; Text; Text
ENG
Relevância na Pesquisa
869.9791%
Conference Paper; We consider the design of kernels for time-frequency distributions through the phase, rather than amplitude, response. While phase kernels do not attenuate troublesome cross-components, they can translate them in the time-frequency plane. In contrast to previous work on phase kernels that concentrated on placing the cross- components on top of the auto-components, we set up a "don't care" region and place the cross-components there. The close connections between optimal allpass kernels and optimal lowpass kernels provide new insight into signal-dependent time-frequency analysis.

Optimal Phase Kernels for Time-Frequency Analysis

Wisur-Olsen, Fridtjof; Wisur-Olsen, Fridtjof
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Conference paper; Text; Text
ENG
Relevância na Pesquisa
975.2306%
Conference Paper; We consider the design of kernels for time-frequency distributions through the phase, rather than amplitude, response. While phase kernels do not attenuate troublesome cross-components, they can translate them in the time-frequency plane. In contrast to previous work on phase kernels that concentrated on placing the cross-components on top of the auto-components, we set up a "don't care" region and place the cross-components there. The close connections between optimal allpass kernels and optimal lowpass kernels provide new insight into signal-dependent time-frequency analysis.

Measuring Time-Frequency Information Content using the Renyi Entropies

Baraniuk, Richard G.; Flandrin, Patrick; Janssen, A. J. E. M.; Michel, Olivier; Baraniuk, Richard G.; Flandrin, Patrick; Janssen, A. J. E. M.; Michel, Olivier
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Journal article; Text; Text
ENG
Relevância na Pesquisa
772.1248%
Journal Paper; The generalized entropies of Renyi inspire new measures for estimating signal information and complexity in the time-frequency plane. When applied to a time-frequency representation (TFR) from Cohen's class or the affine class, the Renyi entropies conform closely to the notion of complexity that we use when visually inspecting time-frequency images. These measures possess several additional interesting and useful properties, such as accounting and cross-component and transformation invariances, that make them natural for time-frequency analysis. This paper comprises a detailed study of the properties and several potential applications of the Renyi entropies, with emphasis on the mathematical foundations for quadratic TFRs. In particular, for the Wigner distribution, we establish that there exist signals for which the measures are not well defined.

Time-frequency and point process algorithms for cardiac arrhythmia analysis and cardiorespiratory control

Kodituwakku, Sandun
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
EN_AU
Relevância na Pesquisa
878.9186%
Cardiovascular diseases are major causes of disability and premature death globally. In particular, atrial fibrillation is the most common cardiac arrhythmia condition found in clinical practice, and is associated with an increased risk of stroke. Heart rate variability (HRV) and respiratory sinus arrhythmia (RSA) are important indicators of cardiovascular health, and provide useful information on autonomic nervous system inputs to cardiac cycle and cardiorespiratory coupling, respectively. New methods to support the treatment of cardiovascular diseases and identifying efficient ways of measuring cardiovascular health could yield significant benefits. In this thesis, we present a number of advanced algorithms for cardiorespiratory signal processing. We present algorithms for analyzing atrial fibrillation arrhythmia from electrocardiograms (ECG). We propose an orthonormal basis function based representation for fibrillatory waveforms, and use a regularized least square solution for atrial activity extraction from ECG, suppressing more dominant ventricular components. Time-frequency analysis of atrial activity is used to identify and track fibrillatory frequencies from extracted atrial activity, which provides possible guidance to tailored treatments. In addressing the problem of tracking fibrillatory frequencies...

Multitaper Methods for Time-Frequency Spectrum Estimation and Unaliasing of Harmonic Frequencies

Moghtaderi, AZADEH
Fonte: Quens University Publicador: Quens University
Tipo: Tese de Doutorado Formato: 1515276 bytes; application/pdf
EN; EN
Relevância na Pesquisa
773.0619%
This thesis is concerned with various aspects of stationary and nonstationary time series analysis. In the nonstationary case, we study estimation of the Wold-Cram'er evolutionary spectrum, which is a time-dependent analogue of the spectrum of a stationary process. Existing estimators of the Wold-Cram'er evolutionary spectrum suffer from several problems, including bias in boundary regions of the time-frequency plane, poor frequency resolution, and an inability to handle the presence of purely harmonic frequencies. We propose techniques to handle all three of these problems. We propose a new estimator of the Wold-Cram'er evolutionary spectrum (the BCMTFSE) which mitigates the first problem. Our estimator is based on an extrapolation of the Wold-Cram'er evolutionary spectrum in time, using an estimate of its time derivative. We apply our estimator to a set of simulated nonstationary processes with known Wold-Cram'er evolutionary spectra to demonstrate its performance. We also propose an estimator of the Wold-Cram'er evolutionary spectrum, valid for uniformly modulated processes (UMPs). This estimator mitigates the second problem, by exploiting the structure of UMPs to improve the frequency resolution of the BCMTFSE. We apply this estimator to a simulated UMP with known Wold-Cram'er evolutionary spectrum. To deal with the third problem...

An orthogonal polynomial analogue of the Landau-Pollak-Slepian time-frequency analysis

Erb, Wolfgang
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
769.9791%
The aim of this article is to present a time-frequency theory for orthogonal polynomials on the interval [-1,1] that runs parallel to the time-frequency analysis of bandlimited functions developed by Landau, Pollak and Slepian. For this purpose, the spectral decomposition of a particular compact time-frequency-operator is studied. This decomposition and its eigenvalues are closely related to the theory of orthogonal polynomials. Results from both theories, the theory of orthogonal polynomials and the Landau-Pollak-Slepian theory, can be used to prove localization and approximation properties of the corresponding eigenfunctions. Finally, an uncertainty principle is proven that reflects the limitation of coupled time and frequency locatability.; Comment: 26 pages, 2 figures

Time-Frequency Analysis as Probabilistic Inference

Turner, Richard E.
Fonte: IEEE Publicador: IEEE
Tipo: Article; published version
EN
Relevância na Pesquisa
976.9907%
This is the final published version. It was originally published by IEEE at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6918491.; This paper proposes a new view of time-frequency analysis framed in terms of probabilistic inference. Natural signals are assumed to be formed by the superposition of distinct time-frequency components, with the analytic goal being to infer these components by application of Bayes' rule. The framework serves to unify various existing models for natural time-series; it relates to both the Wiener and Kalman filters, and with suitable assumptions yields inferential interpretations of the short-time Fourier transform, spectrogram, filter bank, and wavelet representations. Value is gained by placing time-frequency analysis on the same probabilistic basis as is often employed in applications such as denoising, source separation, or recognition. Uncertainty in the time-frequency representation can be propagated correctly to application-specific stages, improving the handing of noise and missing data. Probabilistic learning allows modules to be co-adapted; thus, the time-frequency representation can be adapted to both the demands of the application and the time-varying statistics of the signal at hand. Similarly...

Coherence and time-frequency analysis of impulse voltage and current measurements

Dikun,Jelena; Onal,Emel
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 EN
Relevância na Pesquisa
769.2009%
The aim of this paper is to point out the advantages of the use of the time-frequency analysis in the digital processing of waveforms recorded in high voltage impulse tests. Impulse voltage tests are essential to inspect and test insulation integrity of high voltage apparatus. On the other hand, generated impulse currents are used for different test applications such as investigation of high current effects, electromagnetic interference (EMI) testing, etc. Obtained voltage and current waveforms usually have some sort of interferences originated from the different sources. These interferences have to be removed from the original impulse data in order to evaluate the waveform characteristics precisely. When the interference level is high enough, it might not be possible to distinguish signal parameters from the recorded data. Conventional filtering methods cannot be useful for some interference like white noise. In that case, time-frequency filtering methods might be necessary. In this study, the wavelet analysis, which is a powerful time-frequency signal processing tool, is used to recognize the noise of impulse current and voltage data. Thus, the noise sources can be determined by short time Fourier Transform, and a coherence approach is used to determine the bandwidth of noises.

The determination of short circuits and grounding faults in electric power systems using time-frequency analysis

Esen,Vedat; Oral,Bulent; Akinci,Tahir Cetin
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2015 EN
Relevância na Pesquisa
766.5855%
In order to ensure that electrical energy reaches consumers uninterrupted, researchers constantly try to improve power transmission lines. To realize this improvement, probable faults should be analysed through every known method, and new methods should also be implemented. In this study, firstly, the Keban power transmission line located in the Eastern Anatolia region of Turkey was modelled. After that, probable short circuit scenarios were applied on the model, and the short circuit faults in the scenarios were analysed by using the Fourier analysis. The Fourier analysis is a mathematical method that is used as an effective way to determine the sudden changes in the frequency and time band. The study was successful in determining phase and grounding faults through the analyses of the scenarios using Fourier analysis. The fact that the mathematical method was applied on the probable scenarios on a physical model increases the importance of the study.