South Australia has suffered another major blackout, with the state torn from the national electricity grid in the dead of the night because of a fault in Victoria.
Mining giant BHP Billiton says the event, which cut power to about 200,000 SA properties for up to an hour and to the company's Olympic Dam mine for four hours, is a wake up call to federal and state governments to tackle power supply and security.
It came little more than two months after September's statewide blackout though authorities have ruled the two incidents unrelated.
SA Energy Minister Tom Koutsantonis says work is underway to improve the National Electricity Market but that SA's system worked well while on its own.
The blackout started because of an issue in the Victorian transmission network which impacted the flow through the Heywood interconnector, the Australian Energy Market Operator said in a statement on Thursday.
To balance the SA network, 220MW of power was shed from it, causing local power outages for up to an hour from 1.30am.
SA Power Networks confirmed about 30 suburbs were affected in various regions, with power restored to some within 15 minutes.
Mr Koutsantonis said the SA system worked effectively while it was an "island" and gradually returned power to those who lost it from local rescources.
"This wasn't something that began and spread in South Australia. This was a consequence of an event in Victoria," he told reporters.
The SA system was reconnected to the national grid by 5.41am AEDT.
BHP Billiton said the latest power problems showed investment and jobs were being placed in peril by the failure of policy to both reduce emissions and secure affordable and uninterrupted power.
"The challenge to reduce emissions and grow the economy cannot fall to renewables alone," chief executive Andrew Mackenzie said.
"This is a wake-up call ahead of the COAG meeting and power supply and security must be top of the agenda and urgently addressed."
But Mr Koutsantonis said BHP's lack of backup power was an issue for the company.
"They are the largest company in the world and they build generation redundancy almost in all of their mines. Why they haven't done so in Olympic Dam is a matter for them," he said.
The minister said SA was working with other states to improve the National Electricity Market so it is more stable and fairer to all states.
"If we had a second interconnector to the eastern states load could have been drawn from that jurisdiction to prevent power outages," he said.
AEMO said it is working closely with Victoria's transmission network operator AusNet to investigate the exact cause of the event.