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In November 2022, South Australia experienced a ferocious storm that decoupled us from the rest of the electricity grid and felled many local power lines. Functioning as an island, we couldn’t export to the bigger national network, so without that safety valve, SA Power Networks (SAPN) was obliged to pull out all the stops to maintain stability.

They used a pretty blunt instrument. By running the network controls at some substations up to 260 volts, all the solar systems (properly) installed since 2015 tripped off in those areas.

Despite breaking national electricity rules around maximum supply voltage, the blunt instrument worked well.  SAPN broke a few eggs to ensure we could all still cook omelettes. I’d argue that’s much better than giving the noisy regressives any reason to clutch their pearls about rolling blackouts1.

I remember when troglodytes claimed more than 5 or 10% renewables would cause the wires to melt and the sky to fall.

In reality, SA has generated over 70% variable renewable energy for 12 months, and the lights are still on. Unfortunately, good news doesn’t sell copies of The Awfultiser.

In retrospect, the 2016 system black was probably a blessing. The electricity industry has learnt a great deal. Large-scale generators updated their procedures to be more resilient, and small-scale generators benefited from resulting updates to the Australian Standard for solar inverters: AS 4777.2. That standard was updated in 2020 along with SAPN connection requirements to make our renewables-heavy grid more robust.

While the spot market is bought and sold in 5-minute intervals, grid electricity cycles 50 times per second. It must be kept stable from one fraction of a second to the next. Traditionally this has been done by running the generators, literal tons of metal, in large steam-powered plants at 3000 revolutions per minute.

The inertia in these machines provides what the industry calls Frequency Control & Ancilliary Services (FCAS). This system inertia holds frequency within a couple of points of 50 Hz. This is important to keep the pump in your coffee machine happy and make the clock on your oven hold time.

The modern grid in SA now creates inertia with smaller lumps of metal. Some are conventional generators like those at Pelican Point Power Station, but the most recent are four synchronous condensers (AKA syncons) installed at three different points on the network. Now they’re installed, AEMO allows the system to run with just 80 MW of conventional gas-fired inertia, (down from 300 MW). Wind farms and big batteries are now permitted to enter the FCAS market too.

When the 2016 system black occurred, wind was doing half the work, and the Heywood interconnect from Victoria was doing another 30%.

As the towers fell and lines short-circuited, the disturbances caused wind farms to disconnect. Their settings were too fussy, and they jumped off to protect themselves, leaving the network no option but to overload the interconnector, which threw the towel in 7 seconds later. Our gas generation fleet was perfectly capable, but they were mainly stone cold, offline or out for maintenance.

In one case, the newest gas generator was mothballed, and the gas contracts sold off. AEMO had taken their eye off the ball, and the benign hand of the free market had failed.

November 2022, and no network on earth will withstand this sort of onslaught. SAPN are reminding people that you need to stay at least 10 metres from fallen power lines and always assume they’re live.

So, the settings have been changed, and now wind and solar power are obliged to hang on longer and generally be more flexible in emergencies. They will ride through disturbances and recover wherever possible, something a battery-backed inverter is the best at. Tons of spinning metal just isn’t as fast and accurate.

Since forever, the grid has worked as a hub and spoke network. The big thermal plants in the middle spinning power out to the extremities with fairly predictable losses cascading down through the whole system.

Now that we have democratised electricity, with millions of little solar generators pushing back from the bottom, there can be times when there’s too much energy. Left unchecked, the voltage and frequency would climb, driving the generators into overspeed and blowing up other things along the way.

To combat this, SAPN has launched new requirements for new connections so they can, (via third-party agents and an internet connection) assume control in limited circumstances. Initially, this is a matter of putting out what I call the bat signal, a notice which causes large solar farms and many smaller systems to shut down or limit output to zero export.

The next step will be dynamic control, where your solar export limit will be higher (up to 10 kW)  but dynamically throttled by the network when necessary. Dynamic exports have been successfully trialled, with broad adoption starting in July 2023.

Although all new rooftop solar systems will have the necessary controls to switch off in grid emergencies, we’ll still need the aforementioned blunt instrument of forced local voltage rises for the foreseeable future – to deal with all the systems installed between 2015 (when the voltage-cut-off standard became law) and now.

Have you tried switching it off and back on again?

Proper solar monitoring can show what really happened to this residential system. The green line shows SAPN upping the grid voltage suddenly at midday. 15volts is a pretty significant boost and by 3 pm it’s hit 258 volts and this 3kW Fronius has had enough. It takes a siesta until 4:15 pm.

By kicking lots of solar systems off the network, there is a compound effect. Getting rid of the excess generation means they can simply burn gas in conventional plants, which offer conventional control (plus conventional gas profits too no doubt?). The secondary benefit is it creates more load because solar customers become consumers again.

Now, this rubs some people up the wrong way, but it’s a measure of the idea that we’re all in this together. Solar customers take a small hit, voluntarily in many cases, to help keep the lights on for everyone.

Two days later, we have another example. This might vary by locality, but at Lewiston the same thing happens. SAPN voltage boosted from 12:45 to 5 pm, during which time the solar power system cuts out for a little over an hour.

If you spend a good deal of money on a very particular off-grid style solar and battery system, you can island yourself from the network and continue to run on your own solar.

I recommend the Selectronic SP Pro, but it’s an expensive way to assume full control. Most grid hybrid systems will not disconnect when the grid voltage goes too high: they’re programmed to stop generating and standby until either the grid disappears altogether, in which case they operate under “blackout protection mode” or resume operation once the utility supply returns back to normal.

An almost perfect solar bell curve in blue, but this time the rise in voltage from 10 am to 5:30 pm hasn’t been enough to trip the inverter, which uses older AS4777.2015 settings.

The new solar standards have had interesting effects. The more onerous compliance issues have begun to drive some of the blowflies out of the solar industry, which can only be a good thing. Customer WiFi connectivity and commissioning issues have become the bane of many electricians’ existence, so the less able are just going back to ceiling fans and air conditioners.

Personally, I think there could be improvements to make the data connections we are now relying on more robust and easier to install. For example, Victoria uses meshed networks of smart meters that even include street lights. It’s not much of a leap to realise solar and electric car charging need to be managed, maybe air conditioning and pool pumps too.

This is how SAPN summed it up for the punters.

It is great to see that the system has worked despite some enormous challenges. South Australia is arguably at the bleeding edge of the world’s energy transition, running a gigawatt scale grid on ever larger shares of renewable energy for longer and longer periods. Things are genuinely looking up and what we need now is much more long-duration storage, and electrification of transport, which will reduce gas use further.

Legacy solar systems shutting down for a few hours per year after severe storms is a small price to pay. After all – whether it’s an individual house or an entire state – when you go off-grid, you have to make a few compromises until the grid connection comes back online2.

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As a child, Anthony marvelled at his Solarex toy helicopter made with shards of smashed solar cells. With some education, he became a jack of all trades & master of several, qualified contractor, builder, roofer, auto and licenced electrician, veteran car restorer & Dad. After 14+ years of lugging, lifting, plumbing and fixing, wiring, dialling and evangelising for everything solar power-related, on-grid and off, he's got a few yarns to share.

They should allow me to match my solar to me load during these events. Preventing me having my solar run my load and forcing me to purchase power amounts to sanctioned corporate theft.

I have microinverters so matching load to solar output should be configurable.

When solar is remotely shutdown gracefully (using the functionality in all SA solar systems installed since October 2020), there are 2 ways:

#1 Kill power to the inverter via contactor in smart meter #2 Request your inverter to go into zero export

Obviously, #2 is better and does what you want.

Unfortunately, this goes out of the window if SAPN has to raise your voltage.

Greetings Finn, it seems in the interim, while all the ‘smart & powerful power folks’ figure out what best to do, just turn off all exports from home solar. The amount being paid for exported power is so low it can no longer be used in a ‘payback equation’ rationale. Home owners could work on using all their generation themselves – it’s just too complicated sending it to the grid with all the rules and regulations and capacity restrictions … what a lot of humbug we are permitting ourselves and enduring as a society.

We need much smarter thinking than just fix upon fix upon fix. New ideas and bold ones are required. And while we are at it, get all the power lines underground!

Every arvo I turn off the grid from my Schneider XW + as I don’t want to leak any grid power into the loads. Yeah, I’m a skin flint, but by doing this I’m completely islanded and can’t be hurt from grid disfunction, as an added bonus.

98% approx of the year I use no grid power at all, nice yeah!

I’ve never installed a schnitzel myself but I hear they’re ok. The problem that many punters don’t realise is that an off grid and a hybrid machine are different animals. Many on grid hybrid systems won’t have a warranty if you turn the mains supply off for more than 20% of the time. Storage certainly is what we need, especially as transport is electrified.

We simply need more large scale storage to soak up the R/T solar. Powering water heaters during the day will help along those lines.

Sadly Malcom the theft has been going on for a lot longer than just November, but in this instance it was an emergency measure.

I’m thankful that SAPN are dealing with it in a constructive way with flexible exports. (That’s the configuration you need going forward) The Queenslanders are just normalising “NO” as the easy answer by installing extra equipment at your expense to turn your solar off instead of throttle it.

SAPN have been gouging us for years, it was refreshing to have their application for a special $100pa charge aimed at solar customers knocked back under national electricity rules.

The silver lining is that after ETSA was privatised, and the promised reduced prices of power actually panned out into a doubling, people developed a keen interest and a desire to spend economically irrational sums of money on solar, thereby paving the way for the revolution we see continuing now. The privateisers have sown the demise of their golden goose, they just have to spend some of their profits on upgrades now.

https://www.adelaidenow.com.au/news/south-australia/sa-power-networks-owned-by-billionaire-li-kashing-makes-four-times-more-profit-out-of-us-than-its-uk-group/news-story/d00954c420ee1173a7549360eac879b7

Anthony Bennett, “I remember when troglodytes claimed more than 5 or 10% renewables would cause the wires to melt and the sky to fall.”

I’d suggest the only way to shut the naysayers up is to shame them with inconvenient evidence/data – like the emerging trend that RE will likely overtake coal within the next few years as the single biggest energy source for electricity generation in the NEM… https://www.solarquotes.com.au/blog/2022-greenhouse-gas-emissions/#comment-1519069

…and the world. https://twitter.com/fbirol/status/1599997739617914880

“Things are genuinely looking up and what we need now is much more long-duration storage, and electrification of transport, which will reduce gas use further.”

Yep, IMO it can’t come fast enough, to mitigate: * the worsening climate crisis – see: https://www.solarquotes.com.au/blog/2022-greenhouse-gas-emissions/#comment-1518193 * the worsening liquid fuel (particularly diesel) supply crisis: https://www.solarquotes.com.au/blog/fuel-efficiency-standards/#comment-1517396

SA You Can Go Off-Grid With A Million People

Thanks Anthony – a well-researched and correlated looking backwards snapshot.

Looking back is largely research; contrasting with looking forward which relies on applying the science of mathematics to topics.

Only the most experienced and skilful Demographers on earth would tackle analyses relating to predicted global standards of living of all people well into the future, around let’s say for example: Year 2500; 478 years hence. Yet the most experienced and skilful Historians on earth have presented us all with “High Precision” details about global standards of living in the years around 1544 [478 years past].

Might there be any anecdotal connection between what will be going on in every Power engineers office globally in 2500 and what happened in 1544? Yes for sure:- Michael Stifel, a famous German mathematician [1487 – 1567] published his most important work in “Arithmetica Integra” (1544) and was the first to use the term “exponent” and also defined the rules for calculating powers. All engineers today would accept that without understanding the principle of “powers” there is no science of mathematics.

I wonder how many people there will be in SA in 2500, and what their “Electricity Generation Technology Systems” will look like?

478 years hence. Is it even remotely reasonable to forecast with any confidence, that the key “Electricity Generation Technologies” in place now that you have identified in this SA Million People Off Grid article: might still be the key Electricity Generation Technologies in use, but simply “Scaled Up” for an increased SA population [in 2500]?

1. Gas fired Turbines 2. Solar PV Panels 3, Wind Tower Generators 4. Batteries

The answer will predicate and dictate the appropriate forward thinking and planning for the subject.

But focussing entirely on the mathematics; physics; the energy sciences is my suggestion.

One hopes the power supplies in PCs manage to handle voltages up to 253VAC when my Fronius would switch off as I just managed to lose one 8GB DDR4 memory stick out of two – one survived.

Worse was to come as such a change, the drop in memory capacity, confuses the BIOS and led to no booting and the purchase of a new motherboard. Later on my son told me all it would have needed was to hold the power button on OFF for five seconds and that would have restored the BIOS and allowed a boot.

Hopefully there weren’t a lot of electronics damaged by the overvoltage.

A lot of North American electronics is autoswitching 120 / 240 volt supply, so if our supply went to 260 volts the half-secondary wall plug V would have gone to 130 volts and hopefully the stuff would be alright if the grid operator had to do that maneuvre here.

I wouldn’t have expected a supply voltage variation to cause a problem in a computer other than damaging the power supply. The various ouput voltages are usually unaffected by mild voltage surges.

WA’s WEM has been ‘running off the (NEM) grid’ forever – and I’ve never experienced 260 Vac as far as I can recall, to trip out our rooftop PV inverters. And, WEM is very often integrating a higher % of VRE than the NEM, without syncons.

Although, voltage rise was causing voltages approaching our legal limits at our house when we got rooftop PV 6 years ago, which probably explained the measurable increased dissipation in much of our household equipment (running hot, therefore decreasing lifespan). Also the extremely short life of led ceiling lights (< 1000 hours, vs the advertised 25,000 hours).

Fortunately, under some political encouragement Western Power were finally able to drop these high voltages to more reasonable values.

Thanks Ian, I’m not intimate with all of the sandgropers machinations but they certainly are getting on with it, albeit with a few hiccups, like limiting customers to 20amp supply in some rural installations. The thing with SA is that we’ve always been a part of the bigger network so it’s interesting to see how things cope when we’re forced to go it alone. The wheels stayed on thankfully.

FYI – our (older) house has incoming fuses rated at 100amps each. 3 of them, as we have a 3-phase installation.

240x100x3 = 72kW capacity? We should have no problem with an EV fast-charger, once we get one.

That’s a really stout supply Ian. What’s interesting is that SAPN are currently running a trial where they will pay you a bung of 30cents/day if you’ll agree to them being able to throttle the car charging when the grid is struggling. It’s a perfectly sensible arrangement that I expect will become standard practice.

Fascinating, thanks Anthony. So am I reading right, generally houses wired with battery backup tend to avoid the high-voltage shutdowns?

Actually Nick I think it varies from model to model but the only inverter I know for sure will disconnect and island itself from the grid on high voltage is the Selectronic SpPro. There have been a number of complaints from customers who noticed their battery and solar system basically stood aside and laid idle. They let the high grid voltage through to the customer loads without generating or disconnecting.

I agree with a lot of what you say, but I cannot support the networks running voltages at these high levels. The regulations are there for a reason. High voltage will disconnect solar under 4777.2, but it also causes long term damage to electronics. In some cases it will also cause short term faults and outages, which can have serious safety implications. For example, you would never see PG&E supporting this policy given their awful bushfire history.

Giving SAPN a free pass on voltage management is a really terrible precedent. Does this mean that other networks can start running voltages above 255V when they alone deem it necessary? How high is too high?

The evidence shows that networks already run average voltages at 247-249V across the NEM (this was the ESB study usinig Solar Analytics data). We will see these issues more regularly, so let’s figure a sensible and safe way to address them rather than just looking the other way when it’s convenient.

The energy industry as a whole has a poor record of self regulation and self reporting

As you point out, customers are very happy to have dynamic export control. Many “older” inverters have the ability to have this capability retrofitted. That would be a much better approach than allowing networks the ability to operate outside regulatory safety and reliability standards whenever they, and only they, feel it’s necessary.

On a related note, I see that the EV Council seems to be resisting the suggestion that all EV chargers have an equivalent dynamic charge control capability where DNSPs could control charge rates at extreme peak times. Their argument is that EV charging tariff structures will achieve the goal of avoiding network overloading at these peak times. I’m not sure this will be the case and it seems easier to have an EV customer agree to dynamic peak charge control when they buy the vehicle/rapid charger, rather than after the horse (or in this case the EV) has bolted

Firstly I want to say thanks, I really appreciate your input on these forums, you’ve taught me a few things about the minutia of this industry that hand drawn vector diagrams at TAFE utterly miss.

I don’t think it’s really acceptable that SAPN have been flouting the rules but it would appear to be better than the alternative. For now at least it’s making things interesting for us energy nerds and it’s proving what can be done at the bleeding edge.

It would be nice if they were better prepared but what’s more frustrating is that Queensland appears to be imposing extra hardware costs on solar so they can just switch stuff off, as part of the emergency backstop mechanism. You would think they’d have learnt from SAPN about getting on with dynamic export control, that’s where we must be headed.

Synchronous condensers aren’t slow. When connected to the grid their response time is only limited probably by the speed of light. THey are just large spinning masses that will resist changes in frequency.

I’m having trouble understanding why solar inverters had to be disconnected, don’t they have automatic voltage control like a generator does? There should be a point at which they simply stop feeding power into the grid or just enough to maintain a set voltage. The only real problem I can see is one of hunting across the grid but the maths involved trying to understand that risk is well above my pay grade.

My understanding is that most solar inverters do not regulate their output.

Each individual inverter is not nearly powerful enough to change the grid voltage, so voltage regulation is unnecessary. Except it might be, now that there’s enough solar systems.

It’d probably be best if inverters had the capability to regulate in case the grid power is off so that the house / EV could be powered.

It’s getting to the stage where the whole mess needs better integration rather than the brute force move of simply raising the voltage. It’s foreseeable that an event like the article describes could be managed by varying the output of a million inverters and a million heating / cooling systems.

Hi Robert, Inverters on the pre 2015 standards will run at full output then just disconnect at 264 volts.

Post 2015 they will run at full output until reaching 253 volts (which is 230 plus 10%) After that they throttle themselves by 5% for every extra volt the grid rises.

Once they see 258 volts for more than 10 minutes they shut down, and of course if they hit 264 quicker than that they they shut down immediately.

The latest standards mean there are also reactive power and disturbance ride through settings applied post 2020.

Finn, there will be a lot of lay people reading these comments. Could you elaborate on your option 2 ‘Request the inverter to go into zero export’? In the event of a blackout caused by nature or in anticipation of one caused by SAPN is there anyway a person can disconnect from the grid for a few hours and run their house off their solar panels without the need for batteries? A year or so ago I thought there was a suggestion that a Consumption Monitor could achieve this, but I think I was mistaken.

Well designed solar systems installed after October 2020 can have a command sent to them over the internet that puts then in zero export mode – i.e. the solar generation will stay online with just enough solar to cover the household use. This command is very occasionally (currently 1-2 times per year max) sent by a third party at the grid operator’s request.

The article explains how to avoid the very occasional forced grid voltage rise – an on-grid system with batteries that can be manually put in to off-grid mode.

Batteries are required for stability from one second to the next. The latest Fronius inverters will power a 3kW load, if it’s sunny, without a battery. Better than a poke in the eye but it’s a limited functionality. Basically you to run an extension cord to one dedicated outlet and plug the fridge in or charge your phone.

We’ll have a new blog post out on hybrid inverters soon so keep an eye out for that.

Thanks Anthony, I’ll look forward to the post. We are in a situation where we may benefit from any emerging technologies, providing the cost is not prohibitive.

We signed with Fairmont for a new house to replace our crumbling one back in July 2021 (much cheaper to build new than renovate or extend). The slab was laid in August 2022 and the frame in November 2022. Until we get the roof on I can’t get my 3 quotes through SolarQuotes and even then how long would a supplier honour it for? I hope the house will be completed this year. (I have no idea how people are expended to survive if they didn’t have family and friends helping out with accommodation. The situation really is scandalous.)

The builders heads will explode if you ask them to build it reverse brick veneer but air-cell insulation under your new roof cladding isn’t hard to organise.

I would have thought that is relatively easy and cheap to install a relay where your power comes into your premesis where the coil is powered from the grid side. If two wires come to your premise you should have both wired to the relay. Therefore when there is a blackout it will disconnect your house/ solar system from the grid. Your solar system should then run your home as described above. The relay will prevent power from going back into the grid as it will be an open circuit. When power is restored on the grid it will activate the coil/s on the relay and your house will connected to the grid again. The solar system should then recognise it is back on the grid.

For sure the inverter is not going to change the voltage of the grid! Problem is unless the voltage the inverter is outputting isn’t just a little higher than the voltage from the grid at its terminals no current, no power going into the grid. ThA problem that I can see is if the supply from all the inverters exceeds demand how to ensure everyone gets a equitable share of selling their power. I certainly agree the whole system needs to be way smarter but that’s not a simple task modelling the complexities of a grid even when it was only a few big generators.

Please keep the SolarQuotes blog constructive and useful with these 4 rules:

1. Real names are preferred - you should be happy to put your name to your comments. 2. Put down your weapons. 3. Assume positive intention. 4. If you are in the solar industry - try to get to the truth, not the sale. 5. Please stay on topic.

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