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Baseload gas failure nearly pushed S.A. into another system black

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The Australian Energy Market Operator has confirmed that the explosion and fire at the Torrens Island gas plant near Adelaide in early March, and the failure of the two biggest base-load gas generators nearly sent the South Australia grid into another “system black.”

The loss of the two principal baseload generators – Torrens and Pelican Point – to as yet unexplained reasons – made the system unstable for a period of 40 minutes.  It appears to have been held together only by the states’s wind farms, and the inter-connector to Victoria.

AEMO, in a report published a week ago, says there are striking similarities between the “system black” event in September 28, and the events of March 3, when no blackouts actually occurred.

On March 3, the sudden loss of gas-fired generation (410MW in 1.5 seconds and a further 200MW within five minutes), was more dramatic than on September 28, and the Heywood interconnector carried a much higher load for a longer period of time without collapsing.

AEMO said the loss of one 130MW unit after the explosion and fire was understandable, but says it is at a loss to explain why another two units at Torrens tripped and why the 250MW Pelican Point power plant also tripped within 1.5 seconds.

But one thing it does know that adjustments to the “ride through” settings on the state’s wind farm fleet means that they were unaffected by the failures and the dramatic voltage swings that appeared to have taken the state’s “baseload” gas fleet out of action.

“All wind farms in SA successfully rode through a series of three transmission faults in short succession on 3 March, indicating the changes made to their protection system since 28 September 2016 have been successful,” AEMO noted.

It said that AEMO has not identified any sustained reduction in output from the wind farms as a consequence of the faults on the transmission system. It appears to confirm SEMO’s previous assessment that the changes would avoid a similar system black if the September 28 events were repeated.

Premier Jay Weatherill had no doubt what kept the lights on: “Wind farms kept the lights on in South Australia that day,” he told the ABC.

The event also had some other interesting impacts.

aemo march 3 solar Pv

First was the loss of around 400MW of load, which an AEMO spokesman attributes to the “natural response” of modern electronic equipment and appliances such as air conditioners, pool pumps, fridges, fluorescent lights, etc that dropped out on low voltage.

Around 150MW of rooftop solar capacity was also lost, as the PV systems shut off in response to the voltage disturbance.

That caused an increase in demand, as that sudden blip upwards in the graph above illustrates. As the rooftop PV systems recovered and automatically re-connected, their output increased and reduced the demand.

“AEMO will develop better modelling of load and rooftop PV response to severe voltage disturbances, to fully understand the implications for power system security.”

The other interesting aspect is the performance of the interconnector, which reached well beyond its rated capacity and leaped from 495MW before the incident to peak at 963MW after the third unit at Torrens Island tripped and stopped generating.

  

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  • George Darroch

    A lot of lessons here. We live in interesting times.

    • Rod

      Indeed.
      I don’t want to think what would have happened if this had happened about 1pm
      At times PV in SA supplies around 1/3 total generation. >400MW
      If that all drops off during voltage excursions we are in deep doo doo.

      Maybe we need to look at the ride through settings….

  • Stephen Norris

    I think the article means “First was the loss of around 400MW of load” not of generation?

    • Oops. thanks. been distracted by pumped hydro and energy minister stoushes!

      • Stephen Norris

        Wasn’t the press conference with the SA premier today wonderful? Lots happening suddenly.

        • trackdaze

          Very rich of frydenberg professing we need to work with the Nem when by definition the interconnector is “The Nem” but SA is somehow not entitled to use it.

          I think he needs reminding practically the substantive capacity being added in recent years has been in SA.

  • Rod
  • Charles Hunter

    “AEMO will develop better modelling of load and rooftop PV response to severe voltage disturbances, to fully understand the implications for power system security”

    It must be so nice for South Australians to know that they are the guinea pigs for the rest of the nation.

    And how astonishing it is for the rest of us to learn that AEMO can only ever learn anything as a result of problems in South Australia. It’s these Southern Hemisphere Electrons. They have a different spin to those in the Northern Hemisphere.

  • Ray Miller

    AEMO would be better to spend their time modeling and looking at the technical performance of intermittent gas plants. The PV inverters need to meet the standards set by the distributors the characteristics are well know, but looks like AEMO has been hiding under some rock somewhere for the last 20 years.

    Giles, any idea how much and by whom AEMO is paid? What their KPI’s are and if there are any bonus or any negative bonus for performance?

    And for that matter if we have a major intermittent failure at a generating plant do they get off with just the shame of the failure or do they have to provide any compensation free energy? If not why not?
    Or by the way Torrens you need to run at 100% capacity at peak time for the next week, just like Musk, if I fail to deliver its free?

    Sounds like a simple rule change by AEMC to me.

  • Brunel

    If AEMO is saying “3 March” why would you Americanise it and say “March 3”?

  • Matt

    Has anybody bothered to figure out how much extra RENEWABLE energy installation, whether it be wind or solar or whatever, will be needed to push the water back up the hill again? At the times that the pumped storage will be most needed?

  • Les Johnston

    These fossil fuel plants are causing unreliability in electricity supply! What a huge load on the interconnector without a glitch.

  • Chris Fraser

    I’m overjoyed by the new ride-through setting for windfarms. And so glad that it turns out Malcom Turnbull found baseload – not as what he expected, but ultimately what he needed.

  • Rikaishi Rikashi

    Turns out, when you actually start paying attention to these issues, that gas generators are really unreliable.