More than 10,000 homes remained without power on Monday in Buenos Aires City and some areas of Greater Buenos Aires, the National Energy Regulation Body (ENRE) reported.
The government says it will receive a report on the incident from the Wholesale Electricity Market Company Administrator (CAMMESA) within 15 days.
"It's a matter of milliseconds from the time the system is destabilised to when it cuts out. These are systems of protection which prompt total disconnection. We need to know why it happened", Lopetegui said during a press conference Sunday.
The blackout began at around seven o'clock in the morning, just as voters began arriving to polling stations for provincial elections in four Argentine provinces. Voting occurred without major incidents or disruptions, provincial electoral authorities reported.