More than 10,000 Victorian homes remained without power on Monday evening after being hit with unexpected blackouts over the weekend.
The outages hit the state on Sunday as a surge in demand overloaded the grid during a heatwave.
The Australian Energy Market Operator (AEMO) confirmed the outages were caused by grid failures, not a supply shortage, with the state recording its highest operational demand for a Sunday on record.
The state had more than 1380MW of spare capacity during the time of the outages.
“The power system held up in extreme heat from a supply/demand perspective today, but there are local VIC network outages – crews from Powercor, CitiPower, United Energy, Ausnet and Jemena working hard to restore,” AEMO posted on Twitter.
United Energy said crews worked through the night to restore power, but some homes were likely to remain affected until Monday evening.
“The prolonged high temperatures and humidity through the weekend … resulted in multiple power outages,” a United Energy spokeswoman told Reuters.
The cause of the outages has been identified as fuse faults at overloaded substations.