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AEMO report into SA blackout raises questions, answers none

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Image: ABC

Image: ABC

A preliminary report into last week’s blackout in South Australia from the Australian Energy Market Operator says it is clear that it was a “weather event” that sparked 30 seconds of chaos and triggered the collapse of three main transmission lines and ultimately the state-wide blackout.

But the report, although reaching no conclusions, and based on incomplete data, invites the media – and wind farm opponents in Coalition and industry – to cite wind energy as a key factor by inferring that some of the state’s wind farms contributed to the cascading impacts that caused the state-wide outage.

The report was released on Wednesday morning, just two days before a hastily convened COAG energy minister’s meeting on Friday.

This is grist for the mill for that meeting – and it appears its timing serves no other purpose. No doubt it will be seized upon by the Coalition in its campaign against wind farms and its attempts to stop the states from going forward with their own renewable energy programs.

In particular, the Coalition will point to the loss of 315MW of wind power highlighted by AEMO in the press release after the collapse of the last of the transmission lines that preceded the failure of the inter-connector. At which point all the remaining gas and wind generators tripped.

Screen Shot 2016-10-05 at 12.30.05 PM

But there is a question about whether this loss of wind capacity really mattered. The data in the actual report suggests not.

Wind generators were producing a total of 883MW at the time (gas was providing 330MW and 613MW was coming from Victoria) – and had ridden out the loss of the first two transmission lines.

A small amount of wind capacity dropped out after the second transmission line collapsed, possibly – the operators say – as the result of lightning strikes and a software glitch that has since been rectified.

But as this chart below shows, there was no impact on frequency. It was only the failure of the third transmission line at 1615.18 that some generation was lost, the frequency dropped the system went black 1.2 seconds later.

The loss of the third transmission line took away the delivery mechanism for two other wind farms, which suggests it wouldn’t have mattered which power source was operating on that line. Within another half a second, all remaining gas and wind plants had gone after the interconnector tripped.

Screen Shot 2016-10-05 at 3.53.59 PM

The report does not say why this happened, or why they stopped generating. It could be because they had nowhere to send their output. Or that, as mentioned earlier, some were hit by lightning, or tripped after repeated voltage drops.

Nor does the report does not say if the total blackout would avoided by having a brown coal generator on line, or if the outcome would have been any different with no wind power.

The report also point to problems with conventional generation, saying that contracted but un-named providers of “black start” services – peaking gas fired and diesel power stations – failed to deliver and could not be used to restart the main gas generator, meaning the operator had to wait until a new link was established with Victoria.

They are paid millions of dollars to provide this essential service, but failed when needed. The report does not say why, possibly because it won’t even say who.

Indeed, the report is also likely to trigger discussions about the role of AEMO itself, and the actions that it took, or didn’t take, in the lead up to the blackout.

It says, for instance, that  it was on a “heightened state of readiness” with “emergency procedures in place”.

But market players are wondering why it saw no reason to allocate more back-up power, or adjust the flow on the interconnector so that they could respond to any unforeseen events, particularly for the lightning that is frequent in that part of the world.

If it had “reclassified” the potential loss of the interconnector, this would have invoked the provision of 35MW of local FCAS constraint and constrained the interconnector, leaving enough headroom to manage this power flow increase.

Already, the question is being asked: how serious does a storm have to be, and who made the call that this was not serious enough? Many in the market are also expecting a review of the fault ride-through equipment and systems that are rarely tested in real-time.

AEMO has already taken some preventative measures in the interim, placing constraints on wind farms and taking control of the wholesale market – essentially running it as a centrally controlled system rather than an open energy market.

The reason for this is the continued absence of the three main transmission lines, and some smaller lines, which are unprecedented and beyond the system design. It has also reclassified 10 wind farms that it says “did not operate” normally during the weather events.

It effectively means their combined output cannot exceed 600MW, or that of the interconnector. It says this will remain in place until more is known about the issues. AEMO wants to see high speed data from all wind farms in the region in order to confirm that each generator performed in line with their respective agreements.

The preliminary report explains how severe weather moved through South Australia on the afternoon of Wednesday, September 28, with high winds, thunderstorms, 80,000 lightning strikes, hail, and heavy rainfall and even two tornadoes.

The weather, it said, resulted in multiple transmission system faults including, and in the space of 12 seconds, the loss of three major 275 kV transmission lines north of Adelaide.

Screen Shot 2016-10-05 at 12.33.26 PM

The sequence of events as described by AEMO went something like this:

– At 1618 (network time): One line faulted: No change to generation or load. … but 1 transmission line out of service
– Another line faulted (and successful re-connected within 1 second). Then it re-faulted and 2 transmission lines out of service.

– 1 second later, there was about 123MW reduction in wind output.

– 4 seconds later – another transmission fault …. and now 3 transmission lines were out of service

– About 2 seconds later another about 192MW reduction in wind output occurred. This caused the flow across Heywood Interconnector to increase to over 850MW, causing it to trip. In less than half a second the whole state went to “system black”.

The cause of wind farm disconnection is still not clear and is not dealt with by AEMO. There is some suggestion that some wind farms could have been lost because of multiple lightning strikes, or because of protection measures.

Strikes at some turbines may have triggered an automatic shutdown after three successive faults – although these faults could have been caused by lightning or falls in frequency. There are concerns that these turbines should have been configured to ride through more such events.

It wouldn’t be the first time lightning has caused havoc in South Australia. In 2005, a lightning strike forced the Northern brown coal generator to drop from nearly full output to zero, causing the inter-connector to trip and the loss of a number of other conventional power plants.

Still, these are troubling times for the wind industry, and for the solar industry as well, which could also find itself impacted should the states find themselves beaten into submission by the federal government and a baying media crowd.

2909_sastorm_sp

South Australia premier Jay Weatherill says the report shows that it was a weather event and was not a “renewable energy” event.

“Now, armed with that information, we need to attend the national energy ministers meeting on Friday to take steps to ensure that we have a secure, clean and affordable electricity system,” he was quoted as saying by the ABC.

Prime minister Malcolm Turnbull, however, said the state had failed to keep the lights on. “SA has the highest wholesale energy costs in Australia. That is not good for business. It’s not good for a state which needs to get more jobs, [and has] a higher unemployment rate than any other.”

The Clean Energy Council says it was clear that the blackout was caused by the storm that took out the huge electricity pylons and triggered a sequence of “extraordinary events”, and it wouldn’t have mattered if the state was running on coal, gas, nuclear or renewable energy.

“This was a once-in-50-year storm which placed extraordinary stress on the power system, and the cascading events that followed the damage to the transmission system have never been experienced before,” CEO Kane Thornton said.

“Australia’s power network is highly sophisticated with a range of advanced protection and fault ride-through equipment and systems that are rarely tested in real-time. These were put under unprecedented pressure due to the extreme weather events in South Australia.

“No doubt there will be much we can learn to improve the resilience of the electricity system in light of the evolving energy mix and the probability of increased storm events in the future.

“There is no evidence to suggest that maintaining Northern Power Station in operation or the increased role of wind power changed the outcome in these extraordinary events.”

  

  • Analitik

    In 2005, a lightning strike force the Northern brown coal generator to drop from nearly full output to zero, forcing the inter-connector to trip and the loss of a number of other conventional power plants.

    And did the South Australia grid totally blackout in this instance?

    BTW, where has the South Australian energy minister been in all this? Why has the premier been making all the press statements?

    Would it have anything to do with this letter sent to the AEMO in July?
    http://www.abc.net.au/news/2016-10-04/electricity-security-complex-in-sa-says-koutsantonis/7899302

    • Did S.A. grid totally blackout in this instance?
      No.
      Did three transmission lines fall over in this instance?
      No.

    • wideEyedPupil

      Did Chris Ullmann tip you off about his latest effort or are did you find it yourself? It’s interesting non-by-lined (anonymous) news items on ABC online are taking to quoting Uhlmann’s assertions and rubbish rather than industry experts. Eating their own dog food it seems.

    • MikeH

      Ooh a conspiracy theory involving the energy minister. That is sure to explain everything and you can adjust it to suit the changing facts.

    • MG
      • Analitik

        First time he’s popped up in the press at all since the blackout and yet Jay Weatherill has been the one talking to the press all this time. Why’s that?

        And notice he only mentions the Northern coal plant and doesn’t mention Torrens A, Pelican Point and Torrens B unit 2 all being offline during the event. That’s more than double the amount of baseload that was online at the time.

        • Kenshō

          Your using the word “baseload” in association with a fossil fuel generator and this isn’t technically correct. “Baseload” is all the small loads that are used throughout the day and night. Any generator can produce “baseload” e.g. hydro or solar/storage or wind/storage. Those associated with old paradigms often reify “baseload” power as though it were somehow more solid though the term merely refers to minimum demand. The only reason “baseload” power has become synonymous with fossil fuel generators is because fossil fuel generators have inertia and “baseload” power is often all they can efficiently produce. However any form of storage can produce “baseload” power even though storage is minus the inertia, having the added advantage the generation output can ramp up and down quickly for rapidly changing loads.

          “Base load power sources are power stations which can consistently generate the electrical power needed to satisfy minimum demand. That demand is called the base load requirement, it is the minimum level of demand on an electrical grid over 24 hours.”
          https://en.wikipedia.org/wiki/Base_load_power_plant

          • Analitik

            Baseload units are large for economic reasons and as such, they are heavy so they provide the greatest amount of synchronous inertia when online, even when they are not generating much power.

            Play with semantics all you like – the wind turbines and solar PV failed to support the SA grid because their asynchronous operation provides ZERO inertia. I guess they” have to fork out for the more expensive turbines with synthetic inertia circuity in the future.

            BTW how do you arrange for the wind farms or PV to supply the “minimum level of demand on an electrical grid over 24 hours” without vast amounts of costly storage?

          • Kenshō

            You’ve been misled that asynchronous wind turbines are not synchronous. They are synchronous with the grid though asynchronous with their blade speed which is why they are named so compared to their earlier synchronous predecessors.

            See post of Steven F who explains the type of turbines we have and their related level of provision of inertia to frequency changes.

            With adding storage to wind turbines and hence increasing their inertia proportional to the storage added, the storage could be any type of storage e.g. pumped hydro. Your the utility costing person, is that feasible? Batteries have also been added to turbines specifically for frequency stability services:
            https://www.scientificamerican.com/article/world-s-largest-storage-battery-will-power-los-angeles/

    • frostyoz

      Congratulations on the SA energy minister identifying the issues several months in advance of the storm. The letter was to the AEMC (not AEMO), requesting rule changes to deal with the potential instability and inability to cope with the drop in frequency should the interconnector disconnect.

      It’s not a secret letter. The AEMC published the rule change requests (managing fault levels, managing underfrequency) on its web site on 8 September 2016:

      http://aemc.gov.au/Rule-Changes?topicId=0&status=1

      • Analitik

        OK, I got the body wrong. It doesn’t change the fact that the SA energy minister requested a rule change to limit the Heywood imports during periods of high wind generation .

        Why? To ensure more synchronous generators were online in case there were large short circuits or power surges during these periods.

        Why? Because the wind farms don’t stabilise the grid because they operate asynchronously.

        Yet Tom Koutsantonis had been assuring everyone that the SA grid was just fine in all his public statements right up until the blackout.

        • Kenshō

          No an asynchronous wind turbine is not called asynchronous because of whether it can or cannot synchronise with a grid. It refers to blade speed. They are called asynchronous because asynchronous wind turbines evolved after synchronous wind turbines where the blade speed was synchronous with the frequency. Asynchronous wind turbines are a step forward in evolution because they vary the blade speed in relation to the electrical frequency and the result is the wind places less stress on the blades so they last longer.

          1) Asynchronous:

          “An induction generator or asynchronous generator is a type of alternating current (AC) electrical generator that uses the principles of induction motors to produce power. Induction generators operate by mechanically turning their rotors faster than synchronous speed.”
          https://en.wikipedia.org/wiki/Induction_generator

          2) Synchronous:

          “So for a given synchronous generator designed with a fixed number of poles, the generator must be driven at a fixed synchronous speed to keep the frequency of the induced emf constant at the required value, either 50Hz or 60Hz to power mains appliances. In other words, the frequency of the emf produced is synchronised with the mechanical rotation of the rotor.”
          http://www.alternative-energy-tutorials.com/wind-energy/synchronous-generator.html

          • Chris Fraser

            Thanks for that. Rather than reengineer an asynchronous generator, can the frequency of the induced emf be manufactured through a battery (or capacitor) and inverter in line with the grid connection ?

          • Kenshō

            From the little reading I did, the frequency of different models is managed in different ways depending upon the degree the electrical side of the wind turbine is isolated from the mechanical gearing of the wind turbine. Yes, one class of asynchronous wind turbine has total isolation by rectifying the AC from the blades into DC and then inverting the DC back to 50 Hz AC and as you say using its inverter to sync with the grid. In another model capacitors were mentioned. All in all, the asynchronous or synchronous mechanical workings of wind turbines appeared to have no impact on their provision of functionality to synchronise with a grid. Since I’m an electronics technician not in that field, I can’t discern the extent wind turbines can be reconfigured for changes to their purpose. From what I gleaned they either seem manufactured to be stand alone or have their electrical circuitry powered from an active grid or continue working without an active grid by the provision of a battery for their electrical circuitry.

          • frostyoz

            The synchronous / asynchronous debate is a furphy.

            The first real issue is whether the turbines contribute inertia to the AC grid.
            Hydro, gas, coal, nuclear turbines and their generators (and also an AC interconnector) will contribute inertia if they are connected and spinning.
            DC wind turbines, DC solar panels and DC interconnectors, which connect to the AC grid via inverters, will not. The inertia assists in lessening the rate of change of the frequency. In SA the system frequency fell 6-7 Hz per second, faster than the relays could switch off load to respond (3 Hz rate).

            The second issue is whether there is sufficient reserve available to meet the deficiency from the lost generation. This can be from base load generation, peak generation, battery or interconnector, but if it is from generation it needs to be online and spinning, because it is needed within seconds.

            There is typically no reserve available from wind or solar, because they are usually (not always) exporting at their full available capacity prior to the event.

          • Kenshō

            Agreed wind or solar without storage will offer no inertia to change in frequency. NB. it is only fossil fuel generators which have the problem of inertia. The inverter/charger supplied by batteries ramps up and down at almost instantaneous speed. When fossil fuel is removed from the grid, the inertia problem will end.

          • Chris Fraser

            Ok thankyou … so Chris Uhlmann was led astray, given bad advice by the wrong people, and effectively used by vested interests … interesting.

          • Steven F

            sorry guys the wind turbines do provide inertia to the grid. In fact they provide more inertia the than a thermal turbine. The reason is that for the last 20 years wind turbines have been using AC -DC-AC conversion electronics. The generator is allowed to turn at whatever speed it wants to. The variable frequency and voltage output is converted to DC and then converted to fixed frequency AC. Because the output is computer controlled to be a fixed frequency the wind turbines have much more inertia than any thermal power plant can offer. Many wind turbines are now equipped with brownout ride through capability This allows them the support the grid when a brownout is occurring.

            In the preliminary report the Davenport line tripped and 1 second later was reset. immediately after than power loss was detected on several wind farms connected to the davenport line. A sustained frequency loss also occurred after the line was reset immediately at that point the r experienced a frequency drop and voltage ring or oscillation and then the Davenport tripped off again for the final time. Later they found multiple lines all down on the davenport line.

            Basically the data in the report indicates to me that Davenport shorted and tripped, was reset, and then a sustained soft short and a brown out occurred pulling power away from wind farms and other generators, and then the line shorted and the operator locked it out.

            All but two wind farms were connected to that line. So when it was locked out much of the wind power was locked out, the Victoria interconnect then overloaded and shut down.

            I think the grid operator was resetting the power lines too fast. They should have waited and verified the grid was stable before attempting a reset. Also the tower shown in the first picture clearly didn’t have an adequate foundation and the wind simply pulled the foundation out of the ground. That should have never happened.

          • Kenshō

            Thanks for filling us in on some of the technology we have installed and offering your informed interpretation of events. If Australia’s turbine models already have the AC to DC to AC conversion electronics there, shouldn’t it be relatively easy to add battery storage to new wind farms when battery prices are right? Or is it easier to just add utility storage in a seperate installation?

        • frostyoz

          I’m not criticising your analysis. Just ensuring the correct facts are out there.

  • MikeH

    There is a direct correlation between lines going down and loss of wind generation in some cases, not in others. See p10.

    16:18:08 (T-8s) Single-phase-to-ground fault on Davenport – Belalie 275 kV line.

    16:18:09 (T-7s) 123 MW reduction in output from North Brown Hill Wind Farm, Bluff Wind Farm, Hallett WindFarm, and Hallett Hill Wind Farm.

    page 8 – The Bluff and North Brown Hill WFs are connected to Davenport-Belalie line.

    16:18:13 (T-3s) Single-phase-to-ground fault on Davenport – Mt Lock 275 kV line

    16:18:15.1 (T-0.9s) • 86 MW reduction in output from Hornsdale wind farm.• 106 MW reduction in output from Snowtown 2 wind farm.

    page 8 – Hornsdale is connected to Mt Lock-Davenport line.

  • Rob G

    The vested interests have moved into the control room, yikes!

  • MikeH

    Over at The Conversation, some of Australia’s small band of noisy if somewhat clueless nuclear advocates are besides themselves with joy at the blackout. They can’t stop repeating the word FCAS which is quite impressive since most of them only recently discovered what it meant. Chris Uhlmann has been promoted to a demi-god with one of the more bloviating types praising his bravery. They are so frigging stupid that they think if they trash renewables, the coal addicted L/NP will throw them a bone.

    It is a good lesson for SA Labor who setup the nuclear royal commission. These people behave like members of a cult so don’t expect any reward for taking their fantasies seriously. They are busily trashing you at very opportunity.

    • Coley

      Just ask them if they want to buy Hinckley point?

  • MG

    Wow – harsh treatment of the Market Operator in this article – unfairly harsh, in my view. The report is fairly comprehensive and clear where more information is needed (and coming). I did not read any attacks on wind farms – it reads as if any generation on connected to / upstream of the downed transmission lines would have come offline (presumably including Northern PS, were it online). The anti-wind folks will misinterpret any info said publicly by anyone to suit their agenda – I do not believe today’s AEMO report gives them any additional valid fodder.

    If AEMO had “reclassified” the interconnector as suggested, the 3 power stations that supply FCAS Regulation locally within SA would have jacked their prices – the same issue RenewEconomy has criticized previously. It’s a very expensive decision for AEMO to make. Further, 35 MW of FCAS Regulation would have done nothing to rectify the instant supply/demand imbalance after 300 MW of generation tripped (1 second before the interconnector tripped). FCAS regulation is only re-dispatched every 4 seconds, and 35 MW wouldn’t be nearly enough.

    Will be interesting to see how ‘SRAS provider 1’ is treated (by the AER?) after failing to show up. In 2014 AEMO contracted and paid $50mm worth of SRAS services (NEM wide), and the first time they ever need it, it doesn’t show up! Will the provider have to give their payments back? $ figures from this publication: https://www.aemo.com.au/-/media/Files/PDF/Guide-to-Ancillary-Services-in-the-National-Electricity-Market.ashx

    • Mike

      Given the weather forecasts of a deep low from a few days out and presumably the information they were getting from their own wind forecasting software, it does seem a little surprising that they didn’t take a more defensive position.

      According to AEMO report, some of the windfarms were getting wind gusts in the range that would require them to shutdown. So even though that appears not to have happened, why would they not be ready for it at least?

      • MG

        It’s fair to suggest that AEMO could or should have done more to prepare for high winds impacting transmission or generation. However the only thing I can think of that they could have done, would be to limit the Heywood interconnector to a very low level, leaving hundreds of MW of headroom for FCAS to come across from VIC and fill the gap in the event of a supply loss in SA. However doing this has an opportunity cost – and it would have allowed the generators within SA to wield market power and send energy prices higher (as you’d be preventing cheaper imports from VIC to reach the market in SA). Then when a “credible contingency” DOESN’T occur (3 transmission lines don’t blow over, which has literally never happened before), the market cries foul and tells AEMO they’re a bunch of jerks for making an unnecessary administrative decision (to limit the interconnector) which caused everyone in SA to pay high prices. I think AEMO is kinda damned if they do, and damned if they don’t in this regard – I’m giving them the benefit of the doubt until the dust settles and their final report is out.

        • Mike

          It is easy to be wise in hindsight but the BOM were predicting a 1 in 50 year storm. If ever there was going to be a reason to take precautions even if it meant copping higher prices, surely it was then. But as you say, let us wait for the report. Presumably the AER also does one into the performance of the AEMO.

          • Yo Bro

            120 km/h wind gusts is hardly a storm to worry about, its more of a worry that a storm that bareley rates on a severity scale blacked out the entire state

          • MikeH

            I see you are doing the Texas things and bragging about how storms in the NT are stronger.

            Some may well be but the first 2 on this list

            http://www.bom.gov.au/cyclone/about/northern.shtml

            2011 – Tropical Cyclone Grant – maxed out at 118 Km/h
            2011 – Tropical Cyclone Carlos – hit Darwin at 98 Km/h

            No one likes a BS artist.

    • AllanO

      The AEMO report (not by design, I’m sure) provides “the anti-wind folks” potential fodder by showing that it was the loss of wind generation in the mid-North that led to the overload on Heywood and thence the black system.

      The report draws no conclusions on whether these wind generation losses were inevitable given the compromised state of the transmission system north of Adelaide, or whether the windfarms – which seem to have remained electrically connected to non-faulted sections of the transmission lines running south to Adelaide – should have ridden through the events. It seems surprising that AEMO were able to provide no comments or insight from any of the windfarm operators on the nature of (eg electrical or mechanical) or reasons for these generation losses. (Section 3.3).

      • MG

        I agree, good comment. I suppose upcoming iterations of the report will shed more insight. Fodder-reduction might be better achieved if AEMO referred generically to “generation” that came offline (or each generator’s unit ID) rather than identifying each generator as wind/gas/diesel.

  • Stewart Rogers

    Giles goes straight into attack mode when AEMO doesn’t follow his agenda. Can you please be ‘slightly’ more bi-partisan?

    • Kenshō

      In my undergrad as a social worker in social policy, we were taught to be mindful reports can have a “sin of commission” or a “sin of omission”.

  • Math Geurts

    Giles Parkinson is (as always) as paranoid as Turkey’s Erdogan.

    • Coley

      You can complain about Giles, haddaway to Turkey and shoot yer gob off about Erdogan, let’s know how you got on when you get out of nick.

  • Carl Raymond S

    Bottom line, people only remotely care about the cause; what they care about is a fix. They want a fix to the CO2 problem, which means the coal stays in they ground. Start with that and then fix the second problem – reliable affordable clean energy. Yes, it’s hard. Engineers love hard, they live for it. Take a look at what Tesla’s engineers are doing to build a sustainable world AND the world’s first trillion dollar company. Imagine if they had walked away from designing the world’s best cars because it was ‘hard’.
    More Californian thinking, less Detroit thinking please Malcolm. There’s gold in it.

    • dana andrew eiler

      Way to much forward thinking and common sense for this mob of troglodyte charlatans Carl!

    • Ray Miller

      Yes Carl, the current thinking is largely to blame. This major SA outage should be seen as a wake up call and golden opportunity.
      -We know the climate has and is changing with more extreme weather events (and the extremes are getting larger as a result of trapping more energy in the worlds biosphere).
      -We know that our carbon emissions need to drop to zero and then reversed from the latest science.
      -We need to take the many learning from this event and fix any weakness.
      – Looks like the SA structural engineers need to upgrade their skills and worst case wind loading figures.
      – The variable and predictable renewable energy systems are the future and we need to understand them and be able to displace all carbon emitting generation.

    • Farmer Dave

      Well said, Carl. The priority is to leave as much of the fossil fuels in the ground as possible.

  • Kenshō

    The national conversation is often framed as: do we step backwards to fossil fuel FCAS etc or do we keep adding renewable energy to grids? It’s the old baseload versus renewables conflict.

    The third option is adding storage to renewables to offer FCAS.

  • Warner Priest

    Whilst I have not seen the report, with 20 years under my belt as a Protection / Control / Automation specialist engineer, I can confidently say the blackout was as a result of this extreme weather event and the 275KV transmission lines that failed between North and South of SA as a result of this weather. With the 275KV lines between North & South SA failing, a large amount of standing could not be served from the generation in North SA. At this point there would be too much energy being generated in North SA, too much energy coming into the grid in the North of SA with too little load would result in a rising frequency in that islander part of the network, going upwards of our frequency reference being 50Hz. When this happens, whether wind, coal, gas or solar power generation, the network operator and or protection systems would have to trip out generation plant to keep that part of the grid in balance. In the South part of SA, the existing load had to be picked up by the interconnector between Victoria and SA, this line is constrained to 850MW max, it could not deal with the load at the time and load shedding that should have started in the Southern part of the SA network did not happen quick enough and the interconnector tripped and all power to the load in South of SA was lost. There are a number of ways to address this issue, a more robust transmission network, redundancy and a connector or two with more capacity, more peaking plants, gas, battery storage, Solar Storage, hydrogen storage, large (200MW to 800MW), demand managed loads that can pull energy out of the grid when there is too much such as PEM Electrolyzers (SILYZER) and when there is too little generation they can be switched off very quickly, <2sec. PEM Electrolyzers and large scale Hydrogen production is teh. Closest you will get to Pump Hydro storage schemes and finally more distributed energy resources, more wind, solar and gas plants distributed through the energy network and gas plants that can transition to renewable gas in the future.

    • Kenshō

      Example of using wind turbines to add frequency stability to networks:

      “What the Laurel Mountain project was designed to do is called “frequency regulation.” The wind power stored in the batteries feeds more juice onto the grid when power demands increase. When there is too much electricity coming into the system, its batteries suck more into storage. It can make these adjustments in a second, thus saving the excess power to sell at higher prices the next day. It was good for the grid, good for expanding markets for renewable energy and good for the innovator. It led to bigger jobs for AES, including the Los Angeles project.”
      http://www.scientificamerican.com/article/world-s-largest-storage-battery-will-power-los-angeles/

    • AllanO

      The problem with your analysis Warner is that you assume transmission capability to the south from the mid-North windfarms was lost completely. Read the AEMO report carefully and you will see that this was not the case. The faulted transmission segments were north of the windfarms and they seem to have remained online before either dropping output or disconnecting.

      • Warner Priest

        The 275KV line from Belale to Davenport tripped out, the 275KV line from Brinkworth feeding Templers West then tripped out, it is fed from Davenport 275KV sub. Substantial load would have been feed from North Brown Hill WF, Bluff / Porcupine WF, Hallett 1 & 2 Windfarms that feed through 275KV Belalie sub and inturn Davenport and Brinkworth 275KV subs. Its likely that the frequency in the WF Belalie part of the transmission grid would have gone upward of 50HZ, this because there was insufficient load or transmission connections, (increased impedance), to load to keep that part of the network stable. The protection would then have tripped the 4 windfarms out on overfrequency. The third line that went out from Davenport would likely have had the same effect on the Snowtown Wind Farms and Hornsdale. With the sequence of events not clear and the exact configuration / status of the isolators and breakers in that area of the network not known prior to the lines tripping out, most of what I suggest happened would be speculation but plausable. I do think that Wind Power should not take the blame, but a smarter grid is required when you have a high penetration of renewables.

  • Andrea

    Interesting report from AEMO. I have found the reaction to this incident to be very disappointing. Obviously the fossil fuel lobby and the Coalition would use such incidents to attack renewables, and I understand that renewables proponents need to defend wind power at this time. But it has not been helpful that many have been running the line that a statewide blackout was inevitable (which it wasn’t) and that wind power had absolutely nothing to do with it (which it possibly did). I think it would have been better to defend renewables from this attack by saying that depending so heavily on the interconnectors on such a stormy day seems quite risky, and that the RET has been unbalanced, with to a large growth in the amount wind power and not enough attention paid to technologies that can supply FCAS (such as solar thermal and batteries).

    Anyway, I have some observations/questions.
    – It looks like the AGL wind farms dropped significantly in output suggesting that quite a few of their turbines went down but some stayed online. Could this be because their low voltage ride through capability wasn’t sufficient? If they had all stayed online, then perhaps the loss of Hornsdale and Snowtown wouldn’t have led to Heywood tripping
    – Why was the Heywood interconnector allowed to overload? Surely there would be load shedding before this happened?
    – Murraylink didn’t trip until the end. So it had over 100MW spare capacity. I would be interested to see what it was doing before the blackout.
    – The report also suggests that many transmission towers toppled AFTER the blackout. This suggests that the line pushed by some (“22 towers collapsed – of course the statewide blackout was inevitable”) is a tad problematic.

  • Malcolm M

    The inter-connector has some amazing performance, from 500 MW to 900 MW in 5 seconds before it tripped, thanks to generator momentum. The Vic synchronous generators must have shuddered a little as the SA inter-connector demand went from 500 MW to 900 MW to zero in a few seconds.

  • John
  • AllanO

    For anyone interested in the fine detail of what happens in a major disturbance to the power system, this report is an interesting read:
    http://www.aemc.gov.au/getattachment/5185b9e8-6c98-4078-bf5d-7391224e5be7/NEMMCO-Review-of-13-August-2004-Power-System-Incid.aspx

    It covers the loss of something like 1900 MW of generation in NSW in 2004. No system black, but load shedding occurred in all the mainland NEM states. What’s interesting is that quite a few automatic protection mechanisms on generators and other equipment didn’t operate as expected, making the incident’s impacts more severe than they could have been. Nothing to do with wind / non-wind generation but I wouldn’t be surprised if there are a couple of similar themes re the operation of protection mechanisms.

  • Coley

    Pylon are blown over, electricity supplies are disrupted, a picture paints a thousand words.
    The photos of pylons lying on the ground would explain the supply failures to most, why has the argument been moved into the area of ‘generation failure’?

    • Yo Bro

      Why does pylons on the ground equal total system failure for the entire state? The NT gets one of these storms every year, they are classified as a tropical storm and usually we cook up a bbq in the back yard, and our electricity infrastructure is pathetic at best

      • Coley

        Because it was a transmission failure not a generation failure, from what’s been said and reported.
        But the Anti rewnewable lobby want to make it sound like renewables failed, they didn’t, what seems to have been the problem is that the pylons were insufficiently secured, looking at some of the photos, my garden fence posts are better concreted in.

  • Kenshō

    Uhlmann’s latest piece:
    Renewable energy supporters ‘shouldn’t get hysterical over criticism’
    http://www.abc.net.au/news/2016-10-06/uhlmann-on-power-blackout-in-south-australia/7906844?section=environment

    Uhlmann: “The root cause (of the outage) is subject to further analysis being conducted,” it says.

    Here the technical definition of Uhlmann’s logic of looking for a root cause is called “reductionistic”. It is the desire to find a single underlying cause instead of viewing complex events as having correlations with multiple variables.

    Ulhmann: “Now to dare suggest that the state’s heavy reliance on wind generation might have made it’s grid more vulnerable to a blackout is heresy.”

    Once the counsellor removes the reductionism, we see there isn’t enough generation available on the day of SA’s power outage.

    Uhlmann: “First, it is intermittent so all of it has to be backed up by baseload power for those days when the wind does not blow.”

    Wind is a force for generating power like coal or anything else. Wind provides baseload power or contributes to frequency stability when it is provided with storage. Blaming wind or blaming how the wind generator is configured is another example to reduce the wind away.

    Uhlmann: “Second, for an electricity network to function, demand and supply have to be kept near the perfect harmony of 50 cycles (50 hertz) every second of every day. If the frequency gets out of tune it trips the shutdown switch.
    This electrical harmony is called synchronous supply, and thermal power is very good at delivering it. Wind power is asynchronous as its frequency fluctuates with the breeze, so it has to be stabilised by the give and take of other sources of demand and supply.”

    No asynchronous wind turbines don’t vary their frequency output based upon wind speed. The wind speed and the blades are not coupled directly to the 50 Hz frequency. Wind turbines classified asynchronous due to decoupling blade speed are as effective at producing 50 Hz as synchronous wind turbines or coal generators.

    Uhlmann: “To ensure a reliable supply of electricity at an acceptable standard AEMO has frequency ancillary control services in place to deal with rapid changes in the ebb and flow.”

    We imagine Uhlmann is suggesting fossil fuel provides frequency services. In fact any generator setup to do so can provide frequency services including the wind when it has storage added. In peak demand storage discharges energy to the grid and recharges storage when peak demand subsides.

    Uhlmann: “The weather triggers a series of transmission faults and three major 275 kilovolt lines are lost. Then, in two separate events, 315 MW of wind generation is disconnected. This unexplained, rapid loss of wind power is the event that begins the cascade towards blackout.”

    More reductionistic logic attempting to pin the cause of cascading failure to wind, when there is a storm involved and the analysis of wind farms operating as designed to perform relative to their transmission infrastructure is yet to be presented.

    Uhlmann: “There was no reduction in thermal generation.”

    There was fossil fuel generators contracted to provide backup power which failed to come online for their specifically designated purpose of emergency backup. There was not an increase in thermal generation as paid for.

    Uhlmann: In a footnote it adds, “wind farms cannot be used in the initial stages of a power system restoration due to the variable nature of their output”.

    The wind farms produce a reliable 50 Hz AC regardless of the speed the wind blows. If wind farms are big enough relative to the load and are designed to restart themselves (electrical control circuitry provided with battery backup) they can restart a grid. Additionally, wind farms can produce a consistent power output totally decoupled from the wind speed, by providing wind farms with storage. These are policy and configuration issues, not a limit on wind as a technology.

    Uhlmann: “if the state blacks out it can’t be restarted with wind power.”

    If this is a feature required seek manufacturers guidance and implement.

    Uhlmann: “South Australia is already calling for rule changes in the national electricity market because it recognises its reliance on wind and rooftop solar has made the state’s system less secure.”

    No I used to be a communications technician in military installations. Diversity and redundancy is what brings security and reliability.

    Uhlmann: “Finally, we know that the energy market is in transition to cleaner forms of power and that is unstoppable. In time the engineering difficulties posed by wind will be overcome.”

    The technical difficulties have all been overcome. Wind has been installed to add frequency stability or add to peak demand. The technical difficulties remain squarely in the policy realm.

    Uhlmann: “Because, if the lights keep going out, people will lose faith.”

    Agreed. We need more diversity on the grid, in more places throughout the grid, and yes in some instances renewable energy generators may need the provision of storage. The provision of storage by batteries, pumped hydro or molten salt (with solar towers) all add to cost – though all these measures are cheaper than fossil fuel generators and overly centralised and vulnerable transmission infrastructure.

  • Kenshō

    One important revelation from the SA crisis, is every police station (and military installation) should have satisfactory provision of backup power, able to adequately maintain their operational capability. Civilian infrastructure like water pumps, sewerage pumps and the degree to which mobile phone towers have backup power have also been highlighted as concerns. If a grid goes down, these services and utilities need to keep functioning. Renewable energy is ideal for these applications.

  • Kenshō

    The practical dimension of local energy security:
    1) water: is pumped into reservoirs and these reservoirs will empty in a power outage,
    2) sewerage: ditto as above for water,
    3) NBN: if the central NBN signal in a region is up and running, it still needs police stations, fire departments etc to have an NBN router with power so the landlines and internet will still work,
    4) mobile phone towers and building alarm systems: often have a small amount of batteries on a float charge from a grid. In an outage the batteries will become discharged if there is no alternative power source,
    5) vehicle mobile communications like CB’s, phones, GPS run on DC backed up by the alternator and vehicle battery. As long as the vehicle has fuel to start the engine, these communications will keep working as long as the cranking engine for the battery doesn’t get discharged. If a long standing emergency is likely to effect this, a deep cycle battery, PV and/or diesel generator needs to be added,
    6) buildings housing emergency response all need PV/storage in my view, including important federal and state government buildings and local council,
    7) properties: in my view even a small amount of storage with PV could be potentially life saving, maintaining small intermittent loads like water pumps, refrigeration, a kettle, hotplate, communications. It isn’t necessary to think big. Critical systems don’t need much power at all. Big systems are only for heating and air conditioning

    In summary centralised infrastructure can make a country vulnerable and renewable energy is a local compliment to a centralised grid. Even reduced capacity is crucial in an emergency.

  • Analitik
    • Peter G

      The article is neither daring or new, rehashing earlier “analysis” through out he has tweaked out some of his more glaring technical misunderstandings (following public corrections no doubt). He has taken his privelideged position as a newsreader at the ABC to promulgate his perspective as fact.

      Aggressive as ever, in his vanity Uhlmann positions himself as a lone bold heretic battling hordes of turbine evangelicals, to me his tone and intellectual paucity is more that of a C19 cleric goading evolutionists from the house of Lords…

      I am wondering is it is not some kind of job interview…

      • Kenshō

        I’m not political savvy nor do I have a TV, so I’m not informed enough to work out if Uhlmann is career motivated or motivated to protect personal assets. As far as I’m aware, one can’t give feedback when someone writes for the ABC website or tweets. Protects writers from finding out how the general public really feel about their journalism. No accountability.

    • John

      This should keep the pitchfork crowd busy for days. Knock yourselves out. https://t.co/9iBRdN2UOM— Chris Uhlmann (@CUhlmann) October 5, 2016

    • Kenshō

      Below is what you said on the other article, so none of your input is to be taken seriously. You are obviously another person protecting a career or personal assets, who places you before the environment.

      “Yep, about 5% renewables would help reduce fuel loads without compromising the grid stability.”
      http://reneweconomy.com.au/2016/how-gas-generators-cashed-in-and-exploited-hot-water-load-98349