Análise comparativa entre os métodos eletrogeométrico e dos elementos finitos no projeto de SPDA

Abstract

This thesis aims to present some progress and discoveries made in the Lightning Protection Systems area (LPS) regarding some doubts about the Electrogeometric Model for obtaining protection zones against lightning. As an auxiliary method to verify the proper placement of captors on structures, it is suggested the use of the Finite Element Method for the computation of electric fields distribution in order to guide the correct placement of captors. It is known that the electrical charges in thunderstorm clouds create a situation in which a vertical conductor, as a lightning rod, or a horizontal conductor short-circuits some of the equipotential lines created by those charges so that a relatively intense concentration of electric field is produced on them, featuring the protection offered by lightning protection systems. With the aid of specific software used to perform the structure modeling and the simulation using the Finite Element Method, it is possible to view the distribution of electric field on the structure in order to observe points where its intensity is higher or lower compared with the value of the electric field in adjacent structures. Thus, it is possible to determine the areas of greatest risk of lightning incidence, since these are the regions from which upward leaders are formed. The analysis of a Lightning Protection System s down-conductor subsystem complements the study presenting its transient behavior due to the lightning current flow through it. That analysis, performed using the software ATP, allows the verification of the voltage influence, due to the lightning current flow, on the electric field distribution above the structure. Finally, the purpose of this thesis is to present a methodology to complement the Electrogeometric Model in order to take in consideration relevant information about the characteristics nature of lightning.