An “unprecedented” power cut left virtually all of Argentina, Paraguay and Uruguay without electricity.
It appears the failure to reconfigure the system properly following the installation of a transmission line bypass caused the South America blackout.
Argentina’s Energy Secretary Gustavo Lopetegui told a parliamentary investigation that network operator Transener failed to reprogram an emergency system after replacing a high-voltage tower.
So when a short circuit hit the grid, the suddenly imbalanced system couldn’t adjust to it as planned and the grid collapsed across a huge swathe of South America.
The source of the blackout was a failure in the transmission of electricity from the Yacycretá hydroelectric dam.
Preliminary reports revealed a fault on a 500 kV transmission line from Colonia Elía to Belgrano, a suburb of Buenos Aires.
A second 500 kV line from Colonia Elía to Mercedes tripped as automatic protection mechanisms kicked in, while a third line from Colonia Elía to Nueva Campana was out of service at the time owing to construction work.
By the number of people affected, the South America blackout is one of the biggest outages in history.