Unbalanced Systems
Mostrando 13-24 de 26 artigos, teses e dissertações.
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13. Analytical methods for analysis of induction generators connected to eletric power distribution systems / Metodos analiticos para analise de geradores de indução conectados em redes de distribuição de energia eletrica
This thesis presents the development of analytical methods for analysis of squirrel-cage induction generators connected to distribution systems. It was developed analytical methods for evaluation of the following technical issues: large-disturbance stability analysis of induction generators; small-disturbance stability analysis of induction generators; deter
Publicado em: 2008
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14. Análise de Defeitos em Coordenadas de Fase Utilizando Modelagem a Quatro Condutores e Fluxo de Potência Continuado / Fault Analysis by Phase Coordinates Using Four-Wire Modeling and Continuation Power Flow / Análise de Defeitos em Coordenadas de Fase Utilizando Modelagem a Quatro Condutores e Fluxo de Potência Continuado / Fault Analysis by Phase Coordinates Using Four-Wire Modeling and Continuation Power Flow
The effects of neutral wires and system grounding in most power flow and fault analysis methodologies are neglected or merged into phases using Krons reduction method. Thus, the neutral wire and ground currents and voltages remain unknown, restricting the analysis. This work presents a new formulation for fault analysis in the phase domain using three-phase,
Publicado em: 2008
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15. Application of wavelet transform for power quality analysis in electric arc furnace. / Aplicação da transformada Wavelet na análise da qualidade de energia em fornos elétricos a arco.
A new method for the detection and classification of the disturbances that affect the electric power quality in industrial electric systems with electric arc furnaces was developed in this work. During the fusion process of the electric arc furnaces, may occur several events that affect the electric system to which it is inserted may occur, having as charact
Publicado em: 2008
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16. MÃtodos de sincronizaÃÃo de conversores em sistemas de geraÃÃo distribuÃda / Converter synchronization methods for distributed generators systems
The use of frequency converters DC/AC to integrate renewable energy as distributed generation is becoming more common. In such applications, the synchronization with the voltage vector is fundamental to control the converters, particularly considering the new requirements on Low Voltage Ride Through demanded from the distributed generation. This work propose
Publicado em: 2008
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17. Disfunção renal e síndrome de baixo débito cardíaco / Renal dysfunction and low cardiac output syndrome
Background: The low cardiac output syndrome (LCOS) is a serious and complex stage in the pathophysiology of heart failure. Regional blood flow alters depending on different organs and systems, with special impact on the kidney. Acute renal failure is common in patients with LOCS, and it is an independent predictor of increased morbidity and mortality. Object
Publicado em: 2008
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18. Three-phase generalized state estimation / Estimação de estado generalizada trifasica
Since its introduction in 1969 by Fred C. Schweppe, J. Wildes and D. Rom, the power system state estimation has been widely studied. The state estimation is evolving to a more detailed modeling, which considers state variables not commonly used in bus/branch system modeling. A generalized state estimation model, in which switches and circuit breakers are rep
Publicado em: 2007
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19. O trabalho em produção contínua: uma abordagem ergonômica na indústria do petróleo. / The work in continuous production: an ergonomic approach at the oil industry.
This work presents the ergonomics study based on offshore oil production platforms, in operation works for the process plant. The first investigations resulted on indications of disintegrated and unbalanced operational aspects into the production environment. From those evidences, the bibliographical revision indicated the considerations and limits of aspect
Publicado em: 2006
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20. Development and application of shunt active filters for three-phase four-wire systems / Estudo e aplicação de filtros ativos paralelos para sistemas trifasicos com quatro fios
Electricity power quality has gained increased importance in the past few years. The growing number of power electronicsbased loads has created a preoccupation about harrnonic distortion in electric systems. Electricity power quality is an important issue both for energy utilities and consumers. Harrnonic poIlution may cause severe problems to electricity ut
Publicado em: 2005
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21. YAI - Technological support for a solidaristic education / YAI - Apoio tecnologico para uma educação solidaria
During the last decades the cultural industry succeeded in promoting and approving increasingly stricter national and international intellectual property protection laws to the detriment of society at large. Innovations are becoming more and more inhibited due to the fact that new knowledge is always built on previous knowledge with an access control getting
Publicado em: 2005
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22. Metodo Zvus Gauss paralelo para calculo de fluxo de potencia trifasico em redes assimetricas de distribuição de energia eletrica
This work proposes a parallel three-phase power flow method for asymmetrical distribution systems, based on the Zbus Gauss method. Ali the elements of the distribution systems are modeled using per phase quantities and the I = YV formo Moreover, the component models are phase decoupled by using compensation current injections, making the method suitable for
Publicado em: 1999
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23. 18q+, the progeny of a balanced translocation t(1;18)mat: case report with necropsy findings.
A female infant with additional genetic material on the long arm of chromosome 18 is described. Cytogenetic studies of the infant and her mother showed that the altered region resulted from an unbalanced translocation of part of the long arm of chromosome 1. This chromosomal abnormality has not been reported previously, according to a recent registry of abno
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24. Functional impairment trajectories among persons with HIV disease: a hierarchical linear models approach.
OBJECTIVE: This study investigates the level, time course, and stability of functional impairment in a population of persons with symptomatic HIV disease, and illustrates the application of hierarchical linear modeling (HLM) to trajectories of functional status in unbalanced longitudinal data. STUDY POPULATION: We utilized longitudinal interview data on a de