Voltage Instability
Mostrando 1-12 de 20 artigos, teses e dissertações.
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1. Investigation of dynamic instability of three plates switch under step DC voltage actuation using modified couple stress theory
Abstract In this paper dynamical instability of three-layer micro-switch under DC voltage actuation has been studied. Recent studies have used the classical beam theory while leaving out the length scale parameter. In this paper dynamic behavior of the switch has been investigated based on couple stress theory and considering the length scale parameter. To t
Lat. Am. j. solids struct.. Publicado em: 10/07/2018
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2. Application of Iteration Perturbation Method in studying dynamic pull-in instability of micro-beams
In the present study, dynamic pull-in instability of electrostatically-actuated micro-beams is investigated through proposing the nonlinear frequency amplitude relationship. An approximate analytical expression of the fundamental natural frequency is presented by modern asymptotic approach namely Iteration Perturbation Method (IPM). Influences of vibrational
Lat. Am. j. solids struct.. Publicado em: 2014-12
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3. Modeling the pull-in instability of the CNT-based probe/actuator under the Coulomb force and the van der Waals attraction
Carbon nano-tube (CNT) is applied to fabricate nano-probes, nano-switches, nano-sensors and nano- actuators. In this paper, a continuum model is employed to obtain the nonlinear constitutive equation and pull-in instability of CNT-based probe/actuators, which includes the effect of electrostatic interaction and intermolecular van der Waals (vdW) forces. The
Lat. Am. j. solids struct.. Publicado em: 2014-12
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4. Estudo da influência dos parâmetros no processo de soldagem GMAW - arco pulsado
Pulsed gas metal arc welding describes the metal transfer mode involving oscillation (pulsing) of the welding current from a high pulse current in which level drop growth, necking of wire tip and detachment occur, and a low background current, which is applied to maintain the arc. The advantages of the process are: metal transfer without spatter formation an
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/09/2011
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5. VOLTAGE STABILITY PROBABILISTIC ASSESSMENT IN COMPOSITE GENERATION AND TRANSMISSION SYSTEMS / ANÁLISE PROBABILÍSTICA DA ESTABILIDADE DE TENSÃO EM SISTEMAS COMPOSTOS DE GERAÇÃO E TRANSMISSÃO
In some countries, the electric power systems are operating near to their limits due to the absence of investments in the transmission network expansion and natural growth of the electricity demand. This operation condition can also occur in electric power systems in which the transmission expansion is carried out in appropriate way. In this case, the excess
Publicado em: 2009
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6. SIMULAÇÃO ESTÁTICA E DINÂMICA DO CONTROLE DE TENSÃO POR LTC E COMPENSADOR ESTÁTICO / STATIC AND DYNAMIC SIMULATION FOR THE VOLTAGE CONTROL BY LTC AND STATIC VOLTAGE COMPENSATOR
O tema abordado neste trabalho é a observação e análise, em regime permanente e dinâmico, da ocorrência de um fenômeno que já foi observado em condições reais de operação do sistema elétrico brasileiro, que é a relação oposta à usual entre a grandeza controlada e a grandeza controladora. Nestes caso, mesmo que haja margem de recursos para ma
Publicado em: 2008
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7. A Contribution to the voltage stability studies within power systems: new aspects related to load representation. / Uma contribuição ao estudo da estabilidade de tensão em sistemas elétricos de potência: novos aspectos relacionados à representação da carga.
This work investigates the impact of transient and steady state load behavior on power systems voltage stability. In order to do this, a detailed electric power system model is used to reproduce the main aspects of voltage instability and collapse phenomena. The numerical solution of the resulting non-linear differential-algebraic equations is carried out by
Publicado em: 2007
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8. Assessment of voltage stability critical areas of São Paulo State transmission network / Analise da estabilidade de tensão e areas criticas da rede eletrica do Estado de São Paulo
This work investigates the security level of the transmission network of the State of São Paulo with respect to the occurrence of voltage collapse. A number of credible scenarios including base cases (N-0) and single contingency (N-1) cases are considered. PV curve methods are employed for evaluating the voltage stability margin for the selected set of oper
Publicado em: 2006
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9. Fenômenos de instabilidade do arco na soldagem GMAW com gases de baixo potencial de oxidação
The arc welding process with continuous wire and gas protection (GMAW) is currently one of the most important metal joining process. This process has passed through a constant evolution with the introduction of power supplies with electronic control, and the use of techniques to control metal transfer, its operational stability and weld bead formation. Moreo
Publicado em: 2006
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10. Analysis of the vulnerability area and tension stability in electric systems with the insert of wind parks / Análise da área de vulnerabilidade e estabilidade de tensão em sistemas elétricos com a inserção de parques eólicos
The present dissertation evaluates the voltage sag and stability of the real electrical system with the insertion of wind farms. The voltage sags studies serve of base for determination of the vulnerability areas of the electrical system, in which, in turn, the aspects are investigated regarding the voltage instability caused by the integration of wind syste
Publicado em: 2005
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11. 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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12. Instabilities in electrochemical systems with a rotating disc electrode
Polarization curves experimentally obtained in the electro-dissolution of iron in a 1 M H2SO4 solution using a rotating disc as the working electrode present a current instability region within the range of applied voltage in which the current is controlled by mass transport in the electrolyte. According to the literature (Barcia et. al., 1992) the electro-d
Journal of the Brazilian Society of Mechanical Sciences. Publicado em: 2002-07