1,720,966 research outputs found
Frequency-adjustable Positive Sequence Detector For Power Conditioning Applications
No full textThis paper proposes a novel and simple positive sequence detector (PSD), which is inherently self-adjustable to fundamental frequency deviations by means of a software-based PLL (Phase Locked Loop). Since the proposed positive sequence detector is not based on Fortescue's classical decomposition and no special input filtering is needed, its dynamic response may be as fast as one fundamental cycle. The digital PLL ensures that the positive sequence components can be calculated even under distorted waveform conditions and fundamental frequency deviations. For the purpose of validating the proposed models, the positive sequence detector has been implemented in a PC-based Power Quality Monitor and experimental results illustrate its good performance. The PSD algorithm has also been evaluated in the control loop of a Series Active Filter and simulation results demonstrate its effectiveness in a closed-loop system. Moreover, considering single-phase applications, this paper also proposes a general single-phase PLL and a Fundamental Wave Detector (FWD) immune to frequency variations and waveform distortions. © 2005 IEEE.200519281934Fortescue, C.L., Method of symmetrical co-ordinates applied to the solution of polyphase networks (1918) AIEE Transaction, (37), pp. 1027-1140Begovic, M.M., Djuric, P.M., Dunlap, S., Phadke, A.G., Frequency Tracking in Power Networks in the Presence of Harmonics (1993) IEEE Trans. on Power Delivery, 8 (2), pp. 480-486Deckmann, S.M., Marafão, F.P., Time based decompositions of Voltage, Current and Power Functions (2000) IEEE International Conference on Harmonics and Quality of Power, pp. 289-294Jiang, M.C., Pan, C.T., Fast peak detector for variable frequency three-phase sinusoidal signals (1994) IEE Proceedings of Systems and Circuit Devices, 141 (3), pp. 151-156Kaura, V., Blasko, V., Operation of a Phase Locked Loop System Under Distorted Utility Conditions (1997) IEEE Trans. on Industry Applications, 33 (1), pp. 58-63Silva, S.A.O., Donoso-Garcia, P., Cortizo, P.C., Seixas, P.F., A Three-Phase Line-Interactive UPS System Implementation with Series-Parallel Active Power-Line Conditioning Capabilities (2002) IEEE Trans, on Industry Application, 38 (6), pp. 1581-1590Zhan, C., Fitzer, C., Ramachandaramurthy, V.K., Arulampalam, A., Barnes, M., Jenkins, N., Software Phase-Locked Loop applied to Dynamic Voltage Restorer (DVR) (2001) IEEE Power Engineering Society Winter Meeting, 3, pp. 1033-1038Jesus, F.D., Soares, C.F.T., Neto, J.L.S., Watanabe, E.H., Aredes, M., Carvalho, J.R.D., Leal, M., Improvement of a Positive Sequence Components Detector in a Unbalanced Three-Phase System (2003) Brazilian Power Electronics Conference (COBEP)Awad, H., Svensson, J., Bollen, M., Phase Locked Loop for Static Series Compensator (2003) European Power Electronics Conference, , EPEMarafão, F.P., Deckmann, S.M., Pomílio, J.A., Machado, R.Q., A Software-Based PLL Model: Analysis and Applications (2004) Brazilian Automatic Conference, , CBAMarafão, F.P., Deckmann, S.M., Luna, E.K., A Novel Frequency and Positive Sequence Detector for Utility Applications and Power Quality Analysis (2004) International Conference on Renewable Energy and Power Quality (ICREPQ)Aström, K.J., Wittenmark, B., (1997) Computer-Controlled Systems: Theory and Design, , Prentice Hall IncNise, N.S., (2000) Control Systems Engineering, , John Wiley & SonsPeng, F., Ott, G., Adams, D., Application Issues of Active Power Filters (1998) IEEE Industry Application Magazine, 4 (5), pp. 21-30Aredes, M., Fernandes, R.M., Miranda, U.A., Neto, J.L.S., Cordeiro, A.A., Simulation study of a low-cost series compensator for voltage sags, harmonics and unbalances applied to a practical system (2003) Brazilian Power Electronics Conference (COBEP)Deckmann, S.M., Melo, E.F., Evaluation of Voltage Quality Indexes for Harmonic Distortion, Flicker and Sequence Components (1998) IEEE International Conference on Harmonics and Quality of Power, pp. 549-55
Virtual Instrumentation Applied To The Implementation Of Ieee Std 1459-2000 Power Definitions
No full textThis paper discusses the utilization of Virtual Instrumentation to the implementation and evaluation of different power definitions, so that classical formulations and new definitions can be compared without the necessity of acquiring different power meters or analyzers. Accordingly, the definitions of IEEE Standard 1459-2000 for the measurement of power quantities under distorted and unbalanced situations, have been digitally implemented. Thus, several power and power factor components related to the decomposition of the measured voltage and current signals have been obtained. The proposed PC-based Virtual Instrument uses a high performance acquisition board and isolated sensors and transducers. All digital algorithms and routines have been implemented by means of a graphical development system. Regarding to the implementation of STD 1459, this paper also proposes several different algorithms to the required decompositions of voltage, current and power components. © 2005 IEEE.200517121718Czamecki, L.S., What is wrong with the Budeanu concept of reactive and distortion power and why it should be abandoned? (1987) IEEE Trans. on Instrumentation and Measurement, IM-36 (3), pp. 834-837Czarnecki, L.S., Orthogonal decomposition of the currents in a 3phase nonlinear asymmetrical circuit with a nonsinusoidal voltage source (1988) IEEE Trans, on Instrumentation and Measurement, 37 (1), pp. 30-34. , MarchIEEE Tutorial Course on Nonsinusoidal Situations: Effects on Performance of Meters (1990), IEEE Working Group on Nonsinusoidal Situations, 90EH0327-7-PWRRossetto, L., Tenti, P., Using Ac-Fed PWM Converters as Instantaneous Reactive Power Compensators (1992) IEEE Trans, on Power Electronics, 7 (L). , JanuaryDepenbrock, M., The FBD-Method, a generally applicable tool for analyzing power relations (1993) IEEE Trans. on Power Systems, 8 (2), pp. 381-387. , MayPractical definitions for powers in systems with nonsinusoidal waveforms and unbalanced loads: A discussion (1996) IEEE Trans, on Power Delivery, 11 (1), pp. 79-101. , IEEE Working Group on Nonsinusoidal Situations, JanuaryEmanuel, A.E., The Buchholz-Goodhue apparent power definition: The practical approach for nonsinusoidal and unbalanced systems (1998) IEEE Trans. on Power Delivery, 3, pp. 344-350Willems, J.L., Reflections on Apparent Power and Power Factor in Nonsinusoidal and Polyphase Situations (2004) IEEE Trans. on Power Delivery, , AprilEmanuel, A., Summary of IEEE Standard 1459: Definitions for the Measurement of Electric Power Quantities Under Sinusoidal, Nonsinusoidal, Balanced or Unbalanced Conditions (2004) IEEE Trans. On Industry Applications, , May/JuneMarafão, F.P., Electrical Energy Analysis and Control using Digital Signal Processing Techniques (2004), PhD dissertation, Dept. of Systems and Energy Control, University of Campinas, SP, BrazilArseneau, R., Application of IEEE Standard 1459-2000 for Revenue Meters (2003) IEEE PES General Meeting, 50, pp. 87-91IEEE Trial-Use Standard Definitions for the Measurement of Electric Power Quantities under Sinusoidal, Nonsinusoidal, Balanced or Unbalanced Conditions, IEEE Standard 1459-2000, 2000. ISBN 07381-1963-6Cristaldi, L., Ferrero, A., Piuri, V., Programmable Instruments, Virtual Instruments, and Distributed Measurement Systems: What is really useful, innovative and technically sound? (1999) IEEE Instrumentation & Measurement Magazine, pp. 20-27. , SeptemberGoldberg, H., What is Virtual Instrumentation? (2000) IEEE Instrum. & Measurement Magazine, pp. 10-13. , DecemberMarino, P., Nogueira, J., Hemandez, H., Laboratory of Virtual Instrumentation for Industrial Electronics (2000) Proceedings of IEEE International Conference on Industrial Technology, 2Cristaldi, L., Ferrero, A., Monti, A., Ponci, F., Mckay, W., Dougal, R., A Virtual Environment for Remote Testing Of Complex Systems (2005) IEEE Trans, on Instrum. and Measur, 54 (1). , FebruaryWillems, J.L., Ghijselen, J.A., Emanuel, A.E., The apparent Power Concept and the IEEE Standard 1459-2000 (2005) IEEE Trans, on Power Delivery, 20 (2). , AprilParedes, H.K.M., Deckmann, S.M., Marafão, F.P., Voltage Reference Selection: Who's Concerned About? (2005) Brazilian Power Electronics Conference, , COBEP, Recife, BrazilFerrero, A., Peretto, L., Sasdelli, R., Revenue Metering in the Presence of Distortion and Unbalance: Myths and Reality (1998) IEEE International Conf. on Harmonics and Quality of Power, pp. 42-47Marafão, F.P., Deckmann, S.M., Marafão, J.A.G., Power Factor Analysis under Non-Sinusoidal and Unbalanced Systems (2002) IEEE International Conference on Harmonics and Quality of PowerDeckmann, S.M., Marafão, F.P., Time based decompositions of Voltage, Current and Power Functions (2000) IEEE International Conference on Harmonics and Quality of Power, pp. 289-294Emanuel, A.E., Reflections on the Effective Voltage Concept (2003) Sixth International Workshop on Power Definitions and Measurements under Non-Sinusoidal Conditions, pp. 1-7. , MilanMarafão, F.P., Deckmann, S.M., Lopes, A., Robust Delta OperatorBased Discrete Systems for Fixed-Point DSP Implementations (2004) IEEE Applied Power Electronics Conference and Exposition, , APEC, USA, FebruaryPádua, M.S., Deckmann, S.M., Marafão, F.P., FrequencyAdjustable Positive Sequence Detector for Power Conditioning Applications (2005) IEEE Power Electronics Specialists Conference, , PESC, Recife, BrazilAndria, G., Salvatore, L., Inverter drive signal processing via DFT and EKF (1990) IEEProceedings, 137-B (2), pp. 111-11
The Influence Of Voltage Referential In Power Quality Indices Evaluation [a Influência Da Referência De Tensão Na Avaliação De Indicadores De Qualidade De Energia]
No full textThis paper discusses the importance of the voltage referential for power quality monitoring and power systempsilas instrumentation. Considering the operating conditions of simple power circuits, it will be demonstrated that an incorrect choice of the voltages referential may result in erroneous quantification of some power quality indices, especially in three-phase four wire circuits. The use of a virtual reference point and the neutral conductor as reference have been considered and the simulation results confirm the influence of the voltage reference selection in the evaluation of total harmonic distortion, unbalance factors and voltage sags. Finally a way of linking both methods will be discussed by means of Blakesleypsilas theorem. © Copyright 2010 IEEE - All Rights Reserved.618188Depenbrock, M., The FBD-Method, a Generally Applicable Tool for Analyzing Power Relations (1993) IEEE Trans. Power Systems, 8 (2), pp. 381-387. , MayEmanuel, A.E., Reflections on the Effective Voltage Concept Proc. 2003 International Workshop on Power Definitions and Measurements under Non-sinusoidal Conditions, pp. 1-8Willems, J.L., Ghijselen, J.A., The Choice of the Voltage Reference and the Generalization of the Apparent Power Proc. 2003 International Workshop on Power Definitions and Measurements under Non-sinusoidal Conditions, pp. 9-18Willems, J.L., Reflections on Apparent Power and Power Factor in Non-sinusoidal and Poly-phase Situations (2004) IEEE Trans. Power Delivery, , AprWillems, J.L., Ghijselen, J.A., Emanuel, A.E., The Apparent Power Concept and the IEEE Standard 1459-2000 (2005) IEEE Trans. Power Delivery, 20 (2), pp. 876-884. , AprEmanuel, A.E., The Buchholz-Goodhue Apparent Power Definition: The Practical Approach for Nonsinusoidal and Unbalanced Systems (1998) IEEE Trans. Power Delivery, 13 (2), pp. 344-350. , AprMarafão, F.P., (2004) Análise e Controle Da Energia Elétrica Através de Técnicas de Processamento Digital de Sinais, , Ph.D. dissertation, Universidade de Campinas (UNICAMP), Campinas, Brasil(2000) IEEE Trial-Use Standard Definitions for the Measurement of Electric Power Quantities under Sinusoidal, Non-sinusoidal, Balanced or Unbalanced Conditions, pp. 1459-2000. , IEEE StandardMoreira, A.C., Marafão, F.P., Deckmann, S.M., Morales P, H.K., Análise Comparativa das Técnicas de Medição de Potência Baseadas na Recomendação IEEE 1459-2000 e no Método FBD Proc. 2006 IEEE Conferência Internacional de Aplicaçõ es Industriais, 2006Blondel, A., Measurement of Energy of Polyphase currents (1893) Proc. International Electrical Congress Chicago III, pp. 112-117Blakesley, T.H., A New Electrical Theorem (1894) Proc. of the Physical Society of London, 13, pp. 65-67Norma, L., Power Quality Analyser TOPAS 1000 - Faster Completion of Measuring Tasks in Power Networks with a Single Tool, , Hhttp://www.suparule.com/docs/Topas_1000_User_Manual.pdfH, GmbH, Disponível: Acesso em: 9 de agosto de 2007Fluke 1750 Three-Phase Power Quality Recorder - Operator Manual, , http://www.fluke.com.br/brpt/products/ProductManuals.htm?cs_id= 35706(FlukeProducts)&category=PHASE3(FlukeProducts), Available on: Access on: 9 August 2007Power Analyzer - User's Guide, , http://www.google.com.br/search?hl=ptBR&q= model+658+power+quality+analizer+&meta=, Dranetz - BMI, Disponível: Access on: 9 August 2007Registrador de Parâmetros de Qualidade de Energia Elétrica - Guia de Usuário, , http://ias.reason.com.br/reason/admin/uploads/File/produtos_documentos/ RQE-III/R007-GU.pdf, Disponível em: Acesso em: 9 de agosto de 2007Monitor de Tensão para Qualidade de Energia, , http://www.cck.com.br/portugues/index.htm, Disponível em: Acesso em: 9 de agosto de 200
Methodology To Identify The Fundamental Component Of The Grid Voltage Based On The Discrete Fourier Transform (tdf) Recursive Algorithm [metodologia Para Identificação Do Componente Fundamental Da Tensão Da Rede Baseada No Algoritmo Recursivo Da Tdf]
No full textConsidering the increasing demand on digital processing techniques for power electronics and power systems application, this paper deals with the use of a Recursive Discrete Fourier Transform (RDFT) for phase angle, frequency and magnitude identification of the grid fundamental voltages, irrespective to waveform distortions, frequency or amplitude deviations. It will be discussed that if the fundamental frequency of the measured voltages exactly matches the frequency for which the DFT has been designed, an ordinary RDFT algorithm is completely able to provide the necessary information about phase, frequency and magnitude. Two additional algorithms have been proposed to ensure the correct performance if the frequency departs from its nominal value: one for phase correction and another for identification of the fundamental component magnitude. Moreover, it is important to point out that by means of the proposed algorithms, the fundamental component can be identified in less than 2 cicles, independently of the input voltage signal. The analysis of the RDFT has been performed by means of simulation results. In order to evaluate the behavior of the RDFT in a practical system, experimental results regarding to the synchronization of a small generator and the power grid will be presented.183381396Lin, T., Domijan Jr, A., Recursive Algorithm for Real-Time Measurement of Electrical Variables in Power Systems (2006) IEEE Transaction on Power Delivery, 21 (1), pp. 15-22Marafão, F. P.Deckmann, S. M.Pomilio, J. A. and Machado, R. Q (2005). Metodologia de Projeto e Análise de Algoritmos de Sincronismo PLL. Revista Eletrônica de Potência (SOBRAEP), Special Section: Applied Control in Power Electronics, 10 (1), pp. 7-14Sasso, E.M., Sotelo, G.G., Ferreira, A.A., Watanabe, E.H., Aredes, M., Barbosa, P., Investigação dos modelos de circuitos de sincronismo trifásicos baseados na teoria de potências real e imaginária instantâneas (p-PLL e q-PLL) (2002) Congresso Brasileiro de Automática, pp. 480-485. , Natal, BrasilAndria, G., Salvatore, L., Inverter drive signal processing via DFT and EKF (1990) IEE Proceedings-Electric Power Applications, 137, pp. 111-119. , 2 a Ed, ppNakano, K., Ota, Y., Ukai, H., Nakamura, K., Fujita, H., Frequency detection method based on recursive DFT algorithm (2002) Power Systems Computation Conference (PSCC), pp. 1-7. , Session 1, Paper 5, ppBegovic, M.M., Djuric, P.M., Dunlap, S., Phadke, A.G., Frequency Tracking in Power Networks in the Presence of Harmonies (1993) IEEE Transaction on Power Delivery, 8 (2), pp. 480-486Kaura, V., Blasko, V., Operation of a Phase Locked Loop System Under Distorted Utility Conditions (1997) IEEE Transaction on Industry Applications, 33 (1), pp. 58-63Ribeiro, M.V., Deckmann, S.M., Romano, J.M.T., Adaptive filtering, wavelet and lapped transforms for power quality problem detection and identification (2003) IEEE International Symposium on Industrial Electronics, 1, pp. 301-306Cardoso, R. and Gründling, H. A (2006). Single and Three-Phase Kalman Filter Based Synchronization Methods, IEEE 7th International Conference on Industrial Applications (INDUSCON), Recife, BrasilPádua, M.S., Deckmann, S.M., Marafão, F.P., Frequency-Adjustable Positive Sequence Detector for Power Conditioning Applications (2005) IEEE 36th Annual Power Electronics Specialists Conference (PESC), pp. 1928-1934. , Recife, BrasilWang, M., Sun, Y., A Practical Method to Improve Phasor and Power Measurement Accuracy of DFT Algorithm (2006) IEEE Transactions on Power Delivery, 21 (3), pp. 1054-1062Marafão, F.P., (2004) Análise e Controle da Energia Elétrica Através de Técnicas de Processamento Digital de Sinais, , Tese de Doutorado, Departamento de Sistemas e Controle de Energia, FEEC/Unicamp, Campinas, BrasilMcGrath, B.R., Holmes, D.G., Galloway, J., Power Converter Line Synchronization Using a Discrete Fourier Transform (DFT) Based on a Variable Sample Rate (2005) IEEE Transactions on Power Electronics, 20 (4), pp. 877-844Srianthumrong, S. and Sangwongwanich, S (1998). An Active Power Filter with Harmonic Detection Method based on Recursive DFT. 8 thInternational Conference on Harmonics and Quality of Power (ICHQP), 01, pp. 127-132Macías, J.A.R., Expósito, A.G., Efficient Moving-Window DFT Algorithms (1998) IEEE Transactions on Circuits and Systems II: Analog and Digital Signal Processing, 45 (2), pp. 256-260Funaki, T., Matsuura, K., Tanaka, S., Error Correction for Phase Detection by Recursive Algorithm Real Time DFT (2002) Electrical Engineering in Japan, 141 (1), pp. 8-17Oppenheim, A.V., Schäfer, R.W., Discrete-Time Signal Processing (1999) Prentice Hall Processing Series, , 2nd Edition, New Jersey, USAHaykin, S., (1989) An Introduction to Analog and Digital Communications, , John Wiley & Sons, New York, USASubmódulo 2.2. (2002). Padrões de Desempenho da Rede Básica. Operador Nacional do SistemaKundur, P., (1993) Power System Stability and Control, pp. 581-626. , McGraw Hill, New York, USA, ppElgerd, O.L., Control of Electric Power Systems (1981) IEEE Control Systems Magazine, 1, pp. 4-16. , 2a- Ed, ppKumar, I.P., Kothari, D.P., Recent Philosophies of Automatic Generation Control Strategies in Power Systems (2005) IEEE Transactions on Power Systems, 20 (1), pp. 345-357Moreira, A.C., (2006) Uso de Instrumentação Virtual para a Análise da Qualidade da Energia Elétrica, , Dissertação de Mestrado, Departamento de Sistemas e Controle de Energia, FEEC/Unicamp, Campinas, Brasi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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