"Fault" declared in Victoria grid as solar farm constraints drag into summer | RenewEconomy

“Fault” declared in Victoria grid as solar farm constraints drag into summer

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As heavy curtailment of Victoria’s solar farms drags on, AEMO declares a “fault” shortfall that will allow for coordinated response, and puts forward new transmission ideas.

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Gannawarra solar farm and battery storage facility. Source: Wirsol
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The Australian Energy Market Operator has declared a “fault level” shortfall in north west Victoria as it continues to look for solutions to the “system strength” issues that have caused five solar farms to have their output cut in half, and put a question mark over future developments.

The declaration of the “fault level” shortfall in north-west Victoria puts the onus back on local networks – rather than proponents of wind and solar farms – to ensure they have the equipment needed to keep the grid secure.

In short, it means that the local networks will be responsible for the installation of between three and six “synchronous condensers” in the region to guarantee system strength, particularly in the case of the snowballing impact of an outage elsewhere.

A similar declaration was made in South Australia two years ago, leading to a program that will see four such units installed in a coordinated fashion in that state over the next 12 months.

Many developers and grid operators want the same call to be made for parts of NSW, to prevent what they see as a scattergun and more expensive approach when individual projects add the machines on the newly introduced “do no harm” rules. Transgrid has warned that this ruling is making the grid less secure.

Five big and relatively new solar farms – Wemen, Karadoc, Bannerton and Gannawarra in Victoria, along with Broken Hill in NSW – had their output cut in half in mid September when new modelling by AEMO identified the system strength issues in the case of a network fault elsewhere.

The issue had been expected to be resolved “within weeks”, but it has dragged on as developers and inverter suppliers seek a work-around by fine-tuning the inverter settings.

The solar farm owners are particularly frustrated by the delays and the complexities of the process, and the restriction means that some 170MW of potential solar output will be missing from the grid, just as it enters its first major heatwave of what is expected to be a hot summer.

Victoria is also suffering from the absence of a unit at Loy Yang A, whose return to service later this week will not be in time for the first part of the heatwave this Wednesday, while a unit at the Mortlake gas generator is not expected back until the end of the month.

“AEMO has recently limited the number of inverters able to be online for a number of solar farms in north-west Victoria and south-west NSW to manage identified instabilities post contingent in this area of the network,” it says in its newly released report.

“AEMO has re-assessed the system strength projections for the Red Cliffs fault level node and AEMO declares an immediate fault level shortfall of 312 MVA at the Red Cliffs fault level node.” (See location in map below).

The only way to address this, it says, and to allow more “inverter-based” generation – i.e. wind and solar – is through local “synchronous condensers.” It provides a range of scenarios ranging from three large synchronous condensers, six medium-sized condensers at various locations, and nine smaller ones.

This is not the only solution that AEMO is proposing.

Last week, it quietly released an initial proposal for a possible new connector between Victoria and NSW that it says will unlock the pipeline of more than 8GW of wind and solar on the Victoria side of the border, and 20GW of new projects on the NSW side.

It says this new generation will be needed because of the anticipated closure of brown coal generators such as Yallourn, their potential early closure, and the risk of unexpected outages from these ageing coal generators.

It has identified a range of potential solutions (see map above) – from line upgrades to new links to unlock potential renewable energy zones – and is also calling for non-network options (i.e. battery storage), because of the speed in which these could be delivered.

“More than a third of the existing conventional generation capacity in the NEM is expected to withdraw by 2032. Once these generators retire, a new generation mix based on renewables is projected to be lower-cost than new conventional generation,” it says.

But it notes that transfer limitations could reduce access to low-cost generator sources across states, and prevent the efficient and reliable dispatch of supply to Victoria and New South Wales load centres, without additions to the network.

AEMO and Transgrid are inviting submissions before a formal proposal is put under the regulatory investment test procedures that are conducted by the energy regulator, although AEMO has called for a fast-tracking of such decisions under its Integrated System Plan.

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12 Comments
  1. Chris Drongers 3 months ago

    So later this week, Yallourn fails (one turbine blows a hole in some insulation). Rolling blackouts ensue, grid demand cannot be supported to maximum extent by solar in NW Victoria due to limits on system strength and transmission.
    Morrison and Taylor shout that if is all solar and wind’s fault as their output destroyed the economics of maintaining adequate reliable (=new) coal power while inxreased ramping destroyed the mechanical reliabikity of the existing coal plants. They declare a miratorium on new solar and wind until coal plants have a major, taxpayer funded refurbishment.
    I have very little faith that the pro-renewables lobbyists have the imagination and coordination to counter such bellowing from the prime minister and the specialist energy minister.

  2. Ken Dyer 3 months ago

    So we need about $120million for six synchronous condensers. We read elsewhere that the Emissions Reduction Fund has failed it target, leaving about a billion dollars in the kitty. Now a progressive government would invite private networks to lodge EOI’s to obtain grants to install synchronous condensers, wouldn’t they? Or am I dreaming?

  3. Geoff Little 3 months ago

    I am confused here, private enterprise is providing grid synchronous supply, and the grid can’t accept it. Does that tell us that the AEMO and its resources are unable to cope with distributed generators, and is trying playing catchup trying to apply patches? These are just questions– I know there are very smart people in the system, so the questions,– what are the constraints? Band-aids and stop gaps havnt a snowball’s of taking us to 50% renewables, let alone allow the grid to facilitate EV sufficient charging networks by 2025. So what is the strategic plan? Is it the Canberra handbrake as well? They do so dislike to be found to be wrong!

  4. Seriously...? 3 months ago

    So my impression is that the issue is that the inverters, in seeking to maintain voltage and frequency in their local network, could create problems for other areas of the network where the frequency and voltage have moved. In which case the question becomes, for how long can we maintain a model where the voltage and frequency are ‘spongy’ and reliant on ‘inertia’? Sooner or later we need to move to a model where frequency and voltage are synced to some external clock (GPS would do) and principally maintained by inverters with battery backup. In which case the synchronous condenser thing is a backwards step.

    Can ‘synchronous generation’ (turbines) be connected through inverters? Or is that idea too strange for the system engineers?

  5. WildcatterTX 3 months ago

    Total Eren is installing a pretty large synchronous condenser at the Kiamal solar farm near Ouyen. Siemens unit, supposed to be capable of supplying up to 730 MVA of fault current (i read this somewhere else, not sure how accurate that # is, but it’s reactive power rating is about double the other synchronous condensers that have been planned). Not exactly sure how that works, but it was supposed to be completed by end of year, or Q1 2020. Obviously, not in time for the heatwave, but could be better than nothing. Developers in the area may want to show up like a potluck and with a case of beer, and ask them if they need any help!

  6. George Darroch 3 months ago

    If only we had organisations that could plan ahead for a strong and reliable electricity system.

  7. neroden 3 months ago

    I am trying to read the AEMO’s document, and it makes no sense whatsoever, because they haven’t defined the bizarre Australian-only term “available fault level”. In the rest of the world, faults are something to be avoided, but apparently in Australia we want to have more faults and we complain if there isn’t a high enough level of faults?

    What the hell do they mean by “fault current”? Not the international meaning, clearly — under the international meaning, the ideal level of fault current is ZERO, and the “prospective short circuit current” is mainly relevant for sizing circuit breakers.

    It looks like they’re talking about fault current absorption capacity, perhaps? This is mystifying.

  8. JackD 3 months ago

    The hidden gem in this article is AEMO’s (as the Victorian Transmission Planner) quietly submitted joint PSCR with Transgrid, involving a number of options to substantially improve electron sharing betweeen NSW and Victoria, Many of these options proposed involving high capacity 500kV lines between North Ballarat to Bannaby.

    If we’re going to be serious about developing RE in Victorian Northern & NSW Southern areas with high prospects, then transmission will be required to “ship” it to the Major NSW and Victorian Load Centres (Greater Melbourne, Geelong and Greater Sydney, Illawarra and Newcastle). So in my book, AEMO gets a big tick for this one.

  9. Peter Spencer 3 months ago

    so many times things can be traced to the fossil head politicians, and the dirty big polluting company owners and CEO`s , who will do anything, or as with the politicians will do nothing in order to make a system break down in order to con people into blaming renewables.

  10. Ray Miller 3 months ago

    Question; Who pays for all the energy to keep the synchronous condensers spinning? No fee lunches here.

    If we are going to invest in equipment to ‘band-aide’ a problem, just maybe we should invest in equipment which can both walk and chew gum? Surely battery/inverter systems should be used to not only provide the added “fault current” when required but ALL the other grid services to make use of the investment all of the time and leap into this century.

  11. Mark Roest 3 months ago

    Is there any more detail about the battery storage options?

  12. Ian 3 months ago

    The renewables investment has occurred, and the wind and solar farms built and now the business case and demand for supporting network infrastructure needs to be built. The Victorian and NSW governments are now onboard so the transmission lines condensers and batteries will not be delayed.

    This is amazing, within a few years this work will probably be very advanced and Victoria will be able to safely shut down its coal generators. Hopefully the grander schemes like the Marinus link will be well advanced otherwise these competing wind, solar and storage projects will make strengthening the link with Tasmania obsolete.

    If brown coal generator demand is halved in the next two years then you might see renewables percentage increase from25% to 32% just from improving this Western Victoria infrastructure. Other initiatives will improve RE percentage no doubt , but improvements in this rhombus of regret will make impressive strides to a reliable RE dominant grid.

    The business case for battery storage must be particularly good in this area to mitigate the problem of poor transmission capacity. The thing with grid scale batteries is that they are housed in shipping containers. Why not install these rapidly where they are needed and then redeploy them to a different area as transmission infrastructure improves?

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