Transmission line vulnerability to lightning over areas of dense rainforests and large rivers in the Amazon region

Abstract

The vulnerability under lightning conditions of stretches of the 1500km long electrical transmission line Tucurui–Oriximina–Manaus over dense Amazon forest canopy and river crossings is evaluated using a leader progression model (LPM) called ModSalto. We find vulnerability windows (low protection or unsafe) in all crossing stretches that use high towers to comply with environmental restrictions. The values of lightning flashover rates (LFR) reach 0.8277 flashover/year or an equivalent period of 14.49 months for stretches of river crossings, and 0.3403 flashover/year or an equivalent period of 35.26 months for stretches of forest canopy crossing. These numbers are above the computed equivalent ANEEL bidding figure of 0.15 flashover/year for that TL. This methodology uses a map of yearly lightning frequency produced with data from STARNET and SIPAM LLS and the level of lightning protection was evaluated with the electro-geometric model (EGM).