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

AUTOR(ES)
DATA DE PUBLICAÇÃO

2009

RESUMO

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, induced voltages on overhead lines by nearby atmospheric lightning discharges, using some of the most recent research in the area of electromagnetic fields generated by these natural phenomena. Starting from a rigorous mathematical formulation for a lightning channel, as well as for the electromagnetic fields generated by them, for the case of lightning striking the soil directly or an elevated grounded object, it was possible to carry out a comparative study of the urbanization effects close to an overhead line with respect to the increase or decrease of the induced voltages and currents when nearby lightning discharges occur. These effects were analyzed using computational simulations considering variations in some parameters associated with urbanization, such as: number of elevated objects, elevated objects average height, different models for the calculation of attractive radius and occupation or urbanization density. Taking into account the research and the computational program developed in this work, methodologies to evaluate the modifications on the occurrence patterns of lightning induced voltages on overhead lines localized at different urban occupation landscapes or at the vicinity of elevated objects like telecommunication towers, were proposed.

ASSUNTO(S)

indução eletromagnetica telecommunication lines linhas de telecomunicação eletricidade atmosferica electromagnetic compatility electromagnetic indution lightning raios electricity atmospheric compatibilidade eletromagnetica

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