Lightning Channel
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Medidas de corrente contínua em raios nuvem-solo negativos naturais no Brasil: Desenvolvimento de instrumentação e primeiros resultados / Measuring of continuing currents in natural negative cloud-to-ground lightning on Brasil: development of equipment and first results
This work presents the first quantitative study of the continuing current (Icc) in negative cloud-to-ground flashes (-CG) in Brazil. The Icc is a low intensity current that follows some return strokes in -CG flashes. Their long durations result in large charge transfers that are responsible for most lightning damage associated with thermal effects. In this s
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 23/04/2009
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2. Lightning study in association of mesoscale convective systems in the Southest region of Brazil / Estudo das Descargas Elétricas Atmosféricas associadas a sistemas convectivos de mesoescala para a Região Sudeste do Brasil
In this work it is presented the study of 6 years of detected lightning data in association to the occurrence of mesoscale convective systems in the region located between 15S - 27S and 35W - 55W. The Lightning data were provided by FURNAS Centrais Elétricas S.A. for the period 2002-2007. Geostationary satellite images, enhanced in the infrared channel, wer
Publicado em: 2009
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3. The impact of urbanization on the distribution of lightning induced voltages on overhead lines / O impacto do aumento da urbanização nos niveis das tensões induzidas por descargas atmosfericas nas proximidades de linhas de transmissão
Some of the worst damage caused by lightning is indirect, that is, it is caused by electromagnetic fields radiated from this kind of natural phenomenon resulting in electromagnetic compatibility problems or in challenges for designers of surge protection systems and shields against these interferences. This work considers one of these indirect effects, induc
Publicado em: 2009
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4. Medidas de corrente contínua em raios nuvem-solo negativos naturais no Brasil: Desenvolvimento de instrumentação e primeiros resultados / Measuring of continuing currents in natural negative cloud-to-ground lightning on Brasil: development of equipment and first results
This work presents the first quantitative study of the continuing current (Icc) in negative cloud-to-ground flashes (-CG) in Brazil. The Icc is a low intensity current that follows some return strokes in -CG flashes. Their long durations result in large charge transfers that are responsible for most lightning damage associated with thermal effects. In this s
Publicado em: 2009
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5. Características dos relâmpagos nuvem-solo negativos que apresentam múltiplos canais / Characteristics of negative cloud-to-ground lightning showing multiple channels
Um relâmpago nuvem-solo negativo possui em média 3 a 4 descargas. Estas descargas nem sempre seguem o mesmo caminho ao propagarem-se em direção ao solo, podendo gerar mais de um ponto de impacto. Para entender o processo de formação de novos canais (caminhos), foram utilizados neste estudo registros em vídeo com resolução temporal igual ou menor que
Publicado em: 2008
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6. Características dos relâmpagos nuvem-solo negativos que apresentam múltiplos canais / Characteristics of negative cloud-to-ground lightning showing multiple channels
Um relâmpago nuvem-solo negativo possui em média 3 a 4 descargas. Estas descargas nem sempre seguem o mesmo caminho ao propagarem-se em direção ao solo, podendo gerar mais de um ponto de impacto. Para entender o processo de formação de novos canais (caminhos), foram utilizados neste estudo registros em vídeo com resolução temporal igual ou menor que
Publicado em: 2008
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7. Evaluation of the Characteristics of Lightning Return Stroke Electromagnetic Fields Generated by Cloud-to-Ground Lightning. / Avaliação do Comportamento dos Campos Eletromagnéticos Gerados por Descargas Atmosféricas Nuvem-Terra
The occurrence of lightning discharges causes a significant amount of unscheduled supply interruptions in overhead lines of electricity systems, contributing to decrease quality indicators of these systems, even in the case of regions with moderated ground flash density. Focusing on the distribution systems, great part of the problems are related to the indu
Publicado em: 2007
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8. "Avaliação de correntes de descargas atmosféricas através de medições diretas em estruturas altas" / Lightning current discharge evaluation through direct measure in tall towers
The characteristics of lightning currents have a fundamental importance on insulation coordination and on the design of transmission and distribution lines equipment. The CIGRE cumulative frequency distribution curves relative to the main parameters of the first and subsequent downward flashes, which are very frequently used for the evaluation of the lightni
Publicado em: 2005
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9. Investigações relativas ás linhas de transmissão horizontal e vertical de perdas elevadas
This document presents the laboratory measurements and time and frequency domain simulations and calculations regarding the high loss horizontal and vertical transmission lines aiming at improve the knowledge of their performance and well understand the electromagnetic interaction between the lightning channel and the electrical facilities. Impulsive and har
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 12/07/2004
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10. Modelagem matemática de correntes na torre da estação Morro do Cachimbo (Brasil). / Mathematical modelling of current in the Morro do Cachimbo station tower (Brazil).
The effect of an elevated strike object on the measured current in the top and the bottom of Morro do Cachimbo (MCS) station instrumented tower is modeled, considering a current divisor applied at the tower top, and that the channel current is supplied by the current source located at the attachment point. The mathematical formulations of the engineering mod
Publicado em: 2003
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11. Simulação computacional de descargas atmosfericas em estruturas de proteção visando analises de compatibilidade eletromagnetica
This work presents the study of protection against lightning through current transitory coniputational simulation and electromagnetic field results. The development of a new ana1ytical expression of calculation for the electromagnetic field was necessary (in Cartesian coordinates) due to the generality of the possible configurations of a structure. The proce
Publicado em: 2000
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12. Analysis and modelling of negative downward lightning current curves between 1985 and 1994 at Morro do Cachimbo research station (MG) / Analise e modelagem de curvas de corrente de relampagos negativos descendentes entre 1985 e 1994, na estacao de pesquisa do Morro do Cachimbo - MG
In this thesis is presented an analysis of 22 negative descendent lightning collected in Brazil from 1985 to 1994 in the Morro do Cachimbo research station (43o 58 26 W, 20o 0039 S) of the Companhia Energética de Minas Gerais (CEMIG). The historic evolution of direct discharge measurements and the thecniques involved are summarised. From the comparation of
Publicado em: 1998