Overvoltage
Mostrando 1-12 de 18 artigos, teses e dissertações.
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1. Desenvolvimento e uso do compósito de Nb2O5|Cu como revestimento aplicado por aspersão térmica sobre o aço AISI 1020 para proteção contra a corrosão pelo solo em estruturas enterradas
An Nb2O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen
Quím. Nova. Publicado em: 2012
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2. Projeto de filtros para atenuação de correntes de modo comum e de sobretensões em acionamentos de motores elétricos utilizando inversores PWM
The use of inverters in most of electrical motor drives applications has been accompanie by several undesirable effects, such as overvoltage at the motor terminals, circulation of common mode currents and electromagnetic interference problems. The determining factors for most of these problems come with the high switching speed and frequency of the semicondu
Publicado em: 2010
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3. Análise do comportamento de uma linha de um pouco mais de meio comprimento de onda sob diferentes condições de operação em regime permanente e durante a manobra de energização / Analysis of the behavior of an isolated transmission line with a little more than half wave lenght for different operating conditions in steady state and during the energization manouver
This work presents an analysis of the behavior of an isolated transmission line with a little more than half-wave length (2600 km) on fundamental frequency, 60 Hz, connected to an infinite busbar for different operating conditions. The voltage and current profiles for different loading conditions are monitored along the line. An analysis of the influence of
Publicado em: 2010
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4. A influência da resistência de terra nos efeitos das descargas atmosféricas
Existe uma grande preocupação por parte das concessionárias de energia relacionada aos distúrbios que geram sobretensões induzidas na rede elétrica, pois estas atingem os equipamentos sensíveis dos consumidores, causando danos e perdas. Em conseqüência deste quadro, as concessionárias contraem grandes prejuízos financeiros todos os anos devido ao
Publicado em: 2009
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5. Serviços ancilares através da geração distribuíba : reserva de potência ativa e suporte de reativos / Ancillary services provide by distributed generation : active power reserves and reactive support
In order to set the principles for a future regulatory framework in Brazil which involves the participation of distributed generation (DG) to provide ancillary services; this work presents an analysis developed in three broad areas, technical, economic and regulatory. A specific objective of the project is to make an analysis of the use of the DG for the sup
Publicado em: 2009
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6. InteraÃÃo transitÃria entre transformadores de potencial capacitivos e linhas de transmissÃo: uma contribuiÃÃo para minimizar falhas
Coupling capacitor voltage transformers (CCVT) are widely used in power systems for monitoring, protection relays and control aplications. Failure of this equipment may cause unexpected outages of transmission lines (TL), which may result in severe penalties as imposed by the regulatory agency of the government. This fact requires speeding maintenance proced
Publicado em: 2008
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7. Coordenação de isolamento para transitórios de manobra considerando a forma de onda da sobretensões
This work develops a new insulation coordination procedure for transmission lines, considering the influence of the individual characteristics of switching overvoltage waves on the insulation strength. The purpose is to assess how the waveshapes of the transient overvoltages affect the risk of flashover and the air gaps needed, instead of adopting a fixed st
Publicado em: 2006
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8. Digital system for synchronized switching of circuit breakers. / Sistema digital para manobra sincronizada de disjuntores - estudo e especificação funcional.
Nesta dissertação, discorre-se sobre manobra sincronizada de disjuntores. Entre as atividades desenvolvidas para a sua elaboração estão a análise de transitórios causados por manobras em capacitores, reatores e linhas de transmissão, estudos de sobretensão e estudos para a determinação de instantes favoráveis às manobras, sob o ponto de vista de
Publicado em: 2006
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9. Projeto de dispositivo supressor de surto de tensão / Design of voltage surge protective device
This work intends to design a voltage surge suppressor device for telecommunications equipments. The project was conducted with the help of simulation tools. The physical parameters like dopings and dimensions, as well as structures with and without emitter shorts were studied in order to understand their influence on the device behavior and to establish i
Publicado em: 2006
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10. Estudo do desempenho de redes de distribuição rural utilizando dados do sistema de localização de tempestades e da operação do sistema: uma abordagem de Engenharia
The work presents the results of a study based on the application of Lightning Location System (LLS) data and Interruptions data to analyze actual lighting performance of rural distribution lines at Minas Gerais State. The work presents the data used in the development of the case study consisting of three sources of infor mation: lightning data, extracted f
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 16/12/2005
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11. Design, development and implementation of a solid-state pulse modulator for high-power pulse transmitters / Projeto, desenvolvimento e construção de um modulador de pulso estado-solido para transmissores pulsados de alta potencia
This work describes the development of a modular line-type solid-state pulse modulator topology to be applied in magnetron pulsed power radar transmitters, commonly found on tracking, weather and air traffic management radars. This research includes the design, development and assembling of a pulsed modulator for the Barreira do Inferno Launching Center (CLB
Publicado em: 2005
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12. AVALIAÇÃO METROLÓGICA DE VARISTORES DE ÓXIDO DE ZINCO PARA MÉDIA TENSÃO / METROLOGICAL EVALUATION OF ZINC OXIDE VARISTORS OF MEDIUM VOLTAGE
Despite its many benefits, one of the few disadvantages of semiconductor technology is the vulnerability of solid state devices to undesired increase in temperature, voltage and current . Even low voltage pulses can produce interference and damages with several consequences. Thus, as electronics are used in more and more applications, temperature, protection
Publicado em: 2004