WHILE the storm that hit South Australia yesterday, Wednesday 28 September, was large and intense, the winds do not appear to have been particularly severe – at least not relative to what we often experience in northern Australia. For example, a Category 2 cyclone has wind gusts of at least 125 kilometres per hour. According to ABC online news reports gusts reached 83 kilometres per hour in South Australia causing the entire state to black-out. This is the maximum speed that I can find at the Bureau of Meteorology website for Ceduna, which is on the South Australian west coast.
![[image courtesy of Christian Kerr on Facebook]](https://climatelab.com.au/wp-content/uploads/2016/09/AdelaideAchievesZeroEmissions-1-300x300.jpg)
[image courtesy of Christian Kerr on Facebook]
Nevertheless, this is still much less severe than would typically be experienced during a northern Australian cyclone, with the Queensland electricity grid withstanding recent cyclone Marcia (156 km/hr) and even Yasi (285 km/hr gusts) – though there was local damage and power outage.
The Australian Wind Alliance has issued a press release this morning stating that, “South Australia’s wind farms were pumping nearly 1,000 megawatts of energy into the state’s electricity system before yesterday’s mega storm tripped the network.” Specifically 960 megawatts at 4.30pm, covering around 50% of the state’s demand, and that the system failed because “23 transmission pylons” were “knocked out”.
I understand that the particular wind turbines common in South Australia cut-out at 90 kilometres per hour. So, it is plausible given: 1. readings from the Bureau website show wind gusts did not reach 90 kilometres per hour; and 2. data showing wind energy production for South Australia fluctuated between 1200 and 900 megawatts until 4.30pm when it dropped to zero – that the problem was the storm taking out transmission pylons rather than a failure of the wind turbines per se.
Nevertheless, this is unacceptable: the transmission pylons should have been built to withstand much more severe weather events.
UPDATE - 5 OCTOBER 2016
The Australian
Michael Owen, SA Bureau Chief, Adelaide @mjowen
South Australian Premier Jay Weatherill’s insistence that last week’s statewide blackout was wholly related to severe storms has been cast into doubt by the release of a preliminary report by the Australian Energy Market Operator, which shows there was a reduction in wind farm generation at connection points leading up to the outage. The report said more analysis was required to determine what that cause was.
A summary of the AEMO interim report said the storms caused multiple transmission system faults, including the loss of three major 275 kV transmission lines north of Adelaide in the space of 12 seconds.
The report said generation initially flowed through the damaged systems but “following an extensive number of faults in a short period [seconds], 315 MW of wind generation disconnected”.
“The uncontrolled reduction in generation resulted in increased flow on the main Victorian interconnector to make up the deficit,” AEMO said.
This resulted in the interconnector overloading and an automatic-protection mechanism tripping the interconnector to protect it from damage, causing the rest of the state to go black.
... A transmission tower carrying power lines was toppled by high winds near Melrose in South Australia during the storm.
... The AEMO investigation found that the uncontrolled disconnection of 315MW of wind power “increased the flow on the main Victorian interconnector (Heywood) to make up the deficit and resulted in the interconnector overloading”, he said.
“To avoid damage to the interconnector, the automatic-protection mechanism activated, tripping the interconnector and resulting in the remaining customer load and electricity generation in SA being lost.”
“That is not how the electricity system should be operating and the Premier has been badly exposed by this preliminary report... "
The report can be downloaded here: https://www.aemo.com.au/Media-Centre/-/media/BE174B1732CB4B3ABB74BD507664B270.ashx
Re : Wind Measurements – BOM vs Turbines.
The BOM sites measure wind at the standard height of the monitoring station.
This is true but all of the other factors, height, terrain category, direction are accounted for during the structural design by factoring up the wind speed from the 3 second gust design wind speed. Looking at the raw BOM data the storm looked to be a 1 in 25 year event. Houses are designed for 1 in 500 years and Level 1 infrastructure for 1 in 2000 years. PM J Gillard called this robust post disaster design gold plating when she wanted to blame things other than renewables for electricity price rises.
The difference between 1 in 25 to 1 in 2000 year events is of course not linear in terms of wind speed, however the wind pressure does increase to the square of the speed. In summary the towers should have survived pressures 50% higher than they collapsed at.
Were Gas Turbines and other back up power started up before the wind turbines that were supplying 50 % of the load reached their shut down / trip point is my first question
As a second question what was the spinning reserve power available for the total of whatever thermal power etc.
What also was being imported / exported on interstate links . There must be somewhere a sequence of events .... once that is identified then we can all see just what happened
The transmission towers have stood for 60-80 years. They have probably been through much worse storms.
I think that eventually we will find that the cause of the tower collapse was actually the shock of the shock waves initiated by the HV system protection.
When electricity is flowing it puts a stress on the lines similar to when you have water flowing through a hose.
If you cut it off suddenly then it whips around much like a hose does.
I will bet that this is what initiated the tower failure.
Thanks for the update.
How's the rehabilitation to transmission pylon?
Are there damages to wind turbines?
Jennifer,
Thanks for posting the update showing that wind power, as skeptics have predicted, is going to not only cost consumers more in operating costs, but that wind power is also unreliable and a hazard to dependable electricity.
According to the latest, it was in fact the windmills, not the pylons collapsing, that triggered the black out. https://www.aemo.com.au/Media-Centre/-/media/BE174B1732CB4B3ABB74BD507664B270.ashx
@Hunter The four main power transmission lines through the mid north were probably actually built in the first place to carry electricity from three coal-fired power stations at Port Augusta south to the industry and housing around Adelaide.
We have returned to much of the state's "base load" electricity being generated near Adelaide, so these connectors now operate the other way carrying electricity from Torrens Island and other nearby gas turbines north, supplemented by the wind farms they pass on the way.
Unfortunately when three of the four transmission lines fail, the fourth one overloads.
The pylons were built to service the windmills. Who controlled the construction standards, who executed the design of the pylons?
The story that the windmills were producing so much power and then went to zero doesn't really hold up to scrutiny. If ground speed is 87 kph, then the wind at the blade height would have been higher. What is the impact of unreliable, highly variable power being put on the grid without proper conditioning? What is the impact of windmills having forced-buy ins of this sort of unreliable power on infrastructure choices?