Brasilia - The Brazilian government on Wednesday launched an investigation into the causes of a malfunction at the Itaipu hydroelectric plant that led to a massive blackout in Brazil and Paraguay. The power outage that started Tuesday night and lasted well into Wednesday morning affected 40 million people and left about 800 cities - including Sao Paulo, Rio de Janeiro, Belo Horizonte and Brasilia - in the dark, media reports said. Twenty of Brazil's 26 states were affected.
The national operator for the electric system said Wednesday in a statement that a malfunction that initially affected southeastern and central-western Brazil led the transmission system to be automatically disconnected in a domino effect that was felt across the country.
Several hydroelectric plants were impacted, as were Brazil's two nuclear power plants, Angra I and Angra II, which were not operational many hours later, the statement said.
Jorge Samek, general manager of the Itaipu plant that lies on the Brazil-Paraguay border and provides more than 20 per cent of Brazil's energy, said the blackout was not due to power generation problems but to a fault in the transmission system.
"We were operating normally and suddenly the electricity generated by our 18 turbines was not being received by transmission lines. Never before in the history of Itaipu had there been a problem that affected all 18 turbines simultaneously," Samek said.
Brazilian Energy Minister Marcio Zimmermann said the blackout could have originated in the town of Itabera, in the southern state of Sao Paulo, which is the site of a distribution station for electricity that comes from Itaipu. This affected other transmission lines in a "chain reaction."
The power outage began shortly after 10 pm (midnight GMT). The first lights came back on in Rio de Janeiro a few hours later, but the blackout continued in other locations.
Thousands of people were trapped in elevators, subways and suburban trains. Road traffic was chaotic and police stepped up their patrols as an outbreak of crime was feared.
Only large office buildings and hotels with generators were lit up in Sao Paulo, Brazil's financial capital.
Suburban and subway train services were cut off, and the lack of traffic lights wreaked havoc in large cities like Sao Paulo and Rio.
The country's largest airports were also using generators and providing limited emergency service. Many flights had to be cancelled.
Brazil's phone network largely collapsed, as did a major portion of the mobile phone network.
Large parts of Paraguay also went dark, but the blackout there lasted o
