Modelo do leader bidirecional de formação do canal de descargas atmosféricas : nova metodologia de representação do relevo do solo e desenvolvimento de modelo de atratividade de descargas por linhas de transmissão

Abstract

This work continues the development of an advanced model for simulating the process of formation of a negative cloud-to-ground (CG) lighting leader that has been developed over the last few years at the Lightning Research Center (LRC). The model is based on the bidirectional leader theory and uses the Charge Simulation Method (MSC) to calculate the electrical quantities involved in the CG lightning formation process. The proposals of this work can be divided into two stages. The first one presents a new approach for modeling the relief in which chargers are no longer punctual, but surface charges distributed at flat and squared plates placed at the ground surface. Comparing to early developed works this new methodology is physically more consistent. The second stage presents the development of an attractiveness model for upward positive leader initiation from transmission lines placed over a flat ground when a negative CG lighting is occurring around. A specific transmission line geometry was chosen to be represented in this work, but it is possible to create other structures representations using the MSC. A range of scenarios was simulated varying the leader projection point and current intensity. The electric field was analyzed at some specific points to find the attractiveness of structures (towers and cables) and of the flat ground, allowing to conclude the exact point of upward leader initiation in each scenario.