In plain English: the Australian Energy Market Operator’s first major report into South Australia’s blackout
The Australian Energy Market Operator has released its first major report into the statewide blackout. State Political Editor Daniel Wills translates the engineer speak into plain English.
- Double warnings of statewide blackouts
- Weatherill: Little could have been done to prevent blackout
- Blackout blame game begins
The boffins at the Australian Energy Market Operator have released their first major report into the blackout. For every answer it gives, even more questions are raised. Here the engineer speak is translated into plain English to shed light on last Wednesday’s events.
WHAT THEY SAID
The purpose of this report is to provide the AEMO preliminary information regarding the black system event in SA which occurred at 16.18 (Australian Eastern Standard Time) on Wednesday 28 September 2016. This preliminary report reflects initial observations based on data provided to date.
What it means
Something big went down last week and we know everyone wants answers. It’s pretty clear there was a complete blackout on Wednesday afternoon. We know a bit about it, but not everything. We’ll get back to you in a fortnight again, and probably finish up next year.
WHAT THEY SAID
As per standard operating arrangements, AEMO, on 27 September 2016, received advice regarding the potential for a severe weather front to move across SA on 28 September 2016. The electricity system in SA was stable and there was no unusual activity.
What it means
Like everyone who read the paper, we knew there was a storm coming. Things looked fine before it arrived and there wasn’t much to be worried about.
What they said
Immediately before the event, approximately 880 MW of SA wind generation, 330 MW of SA gas generation, and 610 MW of electricity imports via two interconnections with Victoria were collectively supplying 1895 MW of electricity demand to SA.
What it means
Before the storm, about a third of SA’s energy was coming from Victoria. Wind power was producing about half SA’s power. The little bit left was coming from gas.
What they said
The predicted weather front moved through SA on the afternoon of Wednesday 28 September 2016, including high winds, thunderstorms, lightning strikes, hail.
What it means
That storm everyone knew about? Yeah, it showed up as expected.
What they said
The weather resulted in multiple transmission system faults. In the short time between 16.16 and 16.18. Faults included the loss of three major 275 kV transmission lines.
What it means
In two minutes, between 3.46pm and 3.48pm Adelaide time, the storm took out the backbone of power supply in the Mid North as transmission lines fell over.
What they said
At 16.18, following an extensive number of faults in a short period, 315 MW of wind generation disconnected ... also affecting the region north of Adelaide.
What it means
When the big power lines went down, the whole system got a bit wonky. Then about 15 per cent of the power needed to meet the state’s energy demands went off line. All of it was wind. The gas kept going. We’re not really sure why this happened. We’ll get back to you.
What they said
The uncontrolled reduction in generation resulted in increased flow on the main Victorian interconnector to make up the deficit. This resulted in the Heywood Interconnector overloading. The automatic-protection mechanism activated, tripping the interconnector.
What it means
After the wind farms went down, the system tried to get more power from Victoria. A lot of power. The cable wasn’t big enough to handle all the extra electricity SA tried to pull through it. The cable tripped out so Victoria wasn’t also at risk of blackout.
What they said
In this event, this resulted in the remaining customer load and electricity generation in SA being lost (referred to as a Black System).
What it means
Then the entire state went black.
What they said
A Black System start is a predefined and practised plan which was activated following assessment of the electricity system and public and employee safety.
What it means
When you lose all the power in a state, it’s even harder to get it back on.
What they said
At 17.23, AEMO directed the SA transmission network owner ElectraNet to progressively energise the main Victorian interconnector through to Adelaide to start Torrens Island Power Station and provide a basis to allow customer supply to be restored.
What it means
The first thing we did was get the Victorians to send us some power through the interconnector that had failed before, and flick on a gas-fired power station in SA.
What they said
Other generation sources distributed within the generation network also contributed to meeting demand at this time, but detailed data is not available at this time.
What it means
Oh, and also some other power plants. Can’t really say which ones.
What they said
Restoration of electricity supply started in Adelaide at 19.00. By midnight on Wednesday 28 September 2016, 80-90% of electricity (that could be restored) was restored.
What it means
Adelaide started coming back on first. Most of it was done by morning.
What they said
The remaining electricity load could not be restored, as the loss of three of the four 275 kV transmission lines north of Adelaide, together with the unknown status of the fourth line (which required physical inspection), effectively cut the SA transmission grid in two.
What it means
Even though we got Adelaide up and running fairly quickly , the fallen big lines in the north meant people up there still couldn’t get power.
What they said
The northern line confirmed intact was re-energised at 12:15 on Thursday 29 September 2016, allowing some electricity to be restored in the northern region.
What it means
One line we thought fell down didn’t, so we fired it up and turned the lights on for some people in the north on the Thursday. We also had to keep big industry shut down.
What they said
At 21.00 on Friday 30 September 2016, the last remaining segment of transmission supply, the southern Eyre Peninsula, was restored.
What it means
Then every household had the lights back on by Friday night.
What they said
Temporary transmission tower structures owned by ElectraNet have been deployed, and also contributed by network owners in other states to assist in the restoration.
What it means
The damage to the towers was pretty bad. We’re doing the best we can to patch it all together for the next little while. A proper fix could be a week away.
What they said
While the event was triggered by extreme weather, AEMO will conduct a thorough investigation into how each component of the electricity system responded.
What it means
Yeah, there was a storm at the start but then everything just kind of hit the fan after that. Some wind farms turned off, then the supply from Victoria didn’t work and the whole system just totally crapped out. We have to drill down a bit further and find out, especially when lots of states are now looking at closing coal stations and going to renewables.