Estudo e construção de uma antena para gerar campos eletromagnéticos similares aos campos criados por uma descarga atmosférica

Abstract

This work presents a measurement procedure to test lightning protection systems (LPS) of buildings to evaluate the efficiency of their protection systems when a direct lightning discharge strikes the building. To achieve this purpose an experimental study using reduced model techniques was used as a tool for studies of induced electromagnetic fiels inside a building due to direct lightning discharges. First, a preliminary study of linghtning induced voltages on overhead lines using reduced model was done with the aim of choosing the modeling used for the discharge channel. Then, the modeling used for the building, return stroke and ground are presented, as well as the measurement equipments. The measuring of the vertical electric field and induced voltage at the open ends of loops inside the building are presented. Besides reduced model techniques allow us to obtain a lot of information, it is difficult to represent all the components present in a real building. So, the present work has two basic objectives: * to establish a reduced model to study the induced electromagnetic fiels inside a building due to lightning discharges; * to present a measurement procedure to evaluate LPS installed in real buildings. As a result, based on the measurements done in the reduced model implemented, an arrangement for representing the discharge channel was developed. The measurements related to the electric and magnetic fields, as well as the characteristics of the arrangement are presented.