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Topologia de gerador de dist?rbios el?tricos baseada em conversores de pot?nciaChaves J?nior, Emanoel Raimundo Queiroz 19 June 2015 (has links)
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Previous issue date: 2015-06-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Dist?rbios el?tricos como afundamentos de tens?o, interrup??es e desequil?brios de
tens?o podem causar s?rios problemas para os consumidores e para as empresas de gera??o
e transmiss?o de energia. Nos ?ltimos anos, essas empresas de servi?os el?tricos
v?m empregando t?cnicas e equipamentos de prote??o para evitar a ocorr?ncia dist?rbios
ou para amenizar os seus efeitos no sistema. Geradores de dist?rbios s?o utilizados
para analisar o comportamento de equipamentos el?tricos e eletr?nicos frente a poss?veis
dist?rbios el?tricos. A an?lise dessas falhas permite o desenvolvimento equipamentos
de prote??o adequados. Neste trabalho ? apresentado o desenvolvimento de um gerador
de dist?rbios baseado em conversores de pot?ncia que, aliado com uma estrat?gia de
controle, ? capaz de gerar v?rios tipos de dist?rbios sim?tricos como: afundamentos trif?-
sicos, eleva??es trif?sicas e inje??o de harm?nicos. A estrat?gia de controle ? baseada no
controle linear discreto e no controle repetitivo. S?o detalhadas as etapas do projeto dos
controladores e do filtro utilizado para a redu??o de harm?nicos na sa?da. S?o apresentados
os resultados obtidos com simula??es computacionais e os resultados obtidos com
ensaios do sistema implementado em laborat?rio. / Electrical disturbances such as voltage sags, interruptions and voltage unbalances
might cause serious problems for the end-user and for the companies of generation and
transmission of energy. Few years ago, those companies have been using methods and
equipments of protection to avoid the disturbances? presence or to mitigate their effects
on the power system. Disturbances generators are used to analyse the behavior of electrical
and electronic equipments affected by disturbances. The analysis of those failures
allows the development of appropriated protection equipments. In this paper, the development
of a disturbances generator based on power converters is presented. The disturbance
generator developed is able to generate some symmetrical disturbances, such as: voltage
sags, voltage swells and harmonic distortion. The control strategy used in the disturbance
generator is based on discrete and repetitive control. The steps of the design of the control
and of the filter used for reducing harmonic in the output, are detailed in the text. Are
presented the obtained results on computational simulations and the obtained results on
laboratory tests.
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An?lise de impactos na rede de distribui??o de energia el?trica decorrentes da inser??o de sistemas de gera??o fotovoltaicosNunes, Evandro Ailson de Freitas 30 June 2017 (has links)
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Previous issue date: 2017-06-30 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Atualmente, os incentivos ? gera??o de energia el?trica a partir da fontes consideradas
limpas v?m aumentando consideravelmente devido ? escassez dos combust?veis f?sseis,
at? ent?o utilizados em abund?ncia. Em paralelo, unidades de gera??o distribu?da que
utilizam fontes renov?veis tamb?m ganha for?a com a diminui??o dos impostos aplicados
sobre os componentes constituintes dos sistemas de gera??o que utilizam este tipo de
fonte de energia. No entanto, a qualidade da energia el?trica tem sido severamente afetada
pelo aumento do n?mero desses sistemas ligados ?s redes de distribui??o de baixa tens?o.
Com base nisso, nesta disserta??o s?o avaliados os impactos na rede de distribui??o de
energia el?trica decorrentes da conex?o de instala??es fotovoltaicas, em v?rios n?veis de
penetra??o. Nesse intuito, ? realizado um estudo de caso que consiste em operar uma
planta fotovoltaica de 9 kWp conectada ao ponto de acoplamento comum de uma subesta??o
com pot?ncia nominal de 15 kVA. O sistema fotovoltaico utilizado, se divide em:
i) sistema trif?sico fixo de 8 kWp e ii) sistema monof?sico fixo de 1 kWp. A avalia??o ?
feita com base nos indicadores da qualidade da energia el?trica, que indicam as caracter?sticas
de pot?ncia, harm?nicos de tens?o e corrente, desequil?brios entre fases do sistema
e regula??o do fator de pot?ncia. A partir da an?lise desses indicadores, obtidos com
aux?lio da transformada discreta de Fourier, ? realizada uma an?lise do impacto gerado
pela planta fotovoltaica no ponto de conex?o com a rede el?trica. Por meio de resultados
experimentais, os indicadores s?o estimados durante a opera??o do sistema fotovoltaico
e s?o analisados e comparados com o padr?o internacional estabelecido pelo IEEE (do
ingl?s, Institute of Electrical and Electronics Engineers). / Currently, incentives for clean energy generation have been increasing considerably
due to the limitation of fossil fuels, until then used in abundance. In parallel, distributed
generations increase with the reduction of the taxes of the embedded components of the
renewable energy sources. However, the power quality (PQ) has been severely affected
by the increasing number of these types of energy sources connected to low voltage distribution
networks. In this dissertation, the impact on the utility grid will be evaluated
under varying levels of a photovoltaic system penetration. A 9 kWp photovoltaic plant,
composed of three system topologies connected to a 15 kVA substation common coupling
point, will be carried out: a 8 kWp three-phase fixed topology and a 1 kWp fixed
single phase. These photovoltaic systems are power electronics based devices, such as
inverters constructed from semiconductor switches, which, due to their construction and
operation, affect the waveform of the electrical voltage and current, deteriorating the PQ.
From the analysis of PQ indices, obtained by means of discrete Fourier transform, for
power characteristics, voltage and current harmonics, imbalanced levels among system
phases and power factor regulation, an analysis of the impact generated by the photovoltaic
plant at its point of connection with the utility grid will be performed. The indices will
be analyzed and compared to the standards established by the Institute of Electrical and
Electronics Engineers (IEEE) in order to evaluate the impact caused by the connection of
the photovoltaic system at the PCC.
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