You can find at INPE website the reports elaborated by technicians from Atmospherical Electricity Group and Weather Forecast and Climate Studies Center, from National Institute for Space Research. It was analyzed the lightning data and some other atmospheric conditions around Itaipu region on November 10th, when many Brazilian states were hit by a blackout.
Gilberto Câmara, INPE’s director, presented on Thursday the report’s conclusion during the Senate Infrastructure Commission meeting, in Brasilia. Check here the director’s presentation at Senate House.
The thunderbolt incidence report shows that in the afternoon of day 10, a few hours before the blackout happening, the BrasilData Lightening Network registered that the Itaipu system transmission lines were hit many times by atmospheric discharge with intensity superior 50 kA. Now at the time the blackout occurred, at 22h13, the lightning had already decreased considerably.
The discharge detailed analysis registered between 22h10 and 22h16, next to Itaipú transmission lines and the Itaberá substation, points the occurrence of weak electrical discharges and 9.2 km far away of the lines 600kV and more than 30.5km of Itaberá substation. ELAT/INPE has estimated that there is the probability that one of the electrical discharges had hit straight each of the five transmission lines of Itaipu or the Itaberá substation. The probability is less than 15% for weak discharges, that is, with intensity lower than 25 kA. For those above 25kA, the probability is null.
About the weather conditions during the day of November 10th, in Paraná and São Paulo states, the satellite images show that a moderate intensity of a convective system hit the Itaberá region (São Paulo). The Meteorological radar image analysis, by the time the cutoff of electrical power happened, had indicated the occurrence of heavy rain next to Itaberá. According to CPTEC/INPE’s report, the scenery of the time the blackout happened had detected a presence of surface trough and a hot and humid air mass upon most part of São Paulo state that collaborated to the heavy rain occurrence located over the area.
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Source: INPE