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Voltage limits for Queensland’s electricity networks are set to change, bringing the state into line with Australian Standard (AS) 60038 and international best practice. This will enable more solar power systems to be installed – and with less red tape.
Queensland’s Department of Natural Resources, Mines and Energy announced last week voltage limits in Queensland will change from 240 volts +/-6% to 230 volts +10/-6% this year. The new “preferred” operating range will 230 volts +6/-2%.
The major reason for the change has to do with solar power. More than 546,000 solar power systems are installed in Queensland and self-consumption/exports have resulted in issues with network voltage levels rising in some areas, accompanied by the risk of problems with appliance performance or damage.
Voltage Issues Costly, Restrict Solar
In 2016, Energex and Ergon Energy reported around 1,000 complaints from customers related to solar panels and high network voltage. Aside from the frustration to customers, it was costing $2,200 on average to deal with each complaint, plus insurance claims for appliance damage. These and associated network upgrade costs are ultimately passed on to electricity customers.
“To control voltage rise in the past, electricity distributors Energex and Ergon Energy invested significant resources upgrading the network and tightened their solar photovoltaic (PV) connection requirements,” says the Department. “This made it harder, and in some cases more expensive, for customers to connect an exporting solar PV system to the grid.”
Continuing a business-as-usual approach would have resulted in 10 per cent of new applications for new rooftop generation (around 200 per month) requiring modification or being refused. Some applicants would be required to pay an additional cost of between $10,000 and $60,000 toward a network upgrade before a system is installed; effectively making solar a no-go. The situation would have also seen a continued practice of restricting electricity feed-in for some system owners.
More Wiggle Room = 200,000 More Solar Systems
The flexibility for distributors to operate at a lower voltage “floor” limit and decreased incidence of bumping up against the ceiling level will enable more solar power systems to be connected and without so many hoops to jump through says the Department.
It’s a significant number – an estimated additional 200,000 systems or 960 megawatts of capacity could be added as a result of the change. It should also mean less tripping of inverters in existing systems in areas where high voltage issues have been occurring, plus less expenditure on network upgrades.
Status Quo “No Longer Appropriate”
The nominal voltage in Australia was set at 240V nearly a hundred years ago. However, most of the world’s appliances are designed to operate optimally at 230V as a result of the International Electrotechnical Committee (IEC) deciding on 230V as nominal in the early 1980’s. This difference, according to a Regulatory Impact Statement (RIS) published last year, has been costing $400,000 per year in reduced appliance life in Queensland and was considered no longer appropriate for a contemporary electricity network.
“The narrow 12 per cent operating range is inconsistent with the more progressive uniform standard of 230 volts +10 per cent/-6 per cent accepted elsewhere in Australia and overseas, and its permitted 16 per cent range,” said the RIS (PDF).
The Clean Energy Council said the change was “sensible reform”; one it had been advocating for many years.
“Western Australia is now the only state that still relies on the outdated 240V limit,” says the CEC.
If you’ve had problems in the past in getting solar panels installed in Queensland due to network voltage issues and given up in despair, it might be time to start re-examining going solar. Energex and Ergon Energy must comply fully with the new voltage limits from 27 October 2018.
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“The narrow 12 per cent operating range is inconsistent with the more progressive uniform standard of 230 volts +10 per cent/-6 per cent accepted elsewhere in Australia and overseas, and its permitted 16 per cent range,”
Is the “elsewhere”, everywhere elsewhere, or, some places elsewhere?
If it is not everywhere elsewhere, could a comparison between states/territories, please be given?
Also, is Queensland on the NEM grid? If so, how could it hasppen that differnt parts of the same grid, have different operating voltages?
The transmission grid operated at hundreds of kilovolts. Between the national transmission sstems and the low voltage system (LV = 230V single phase or around 400V 3 phase) that your home is connected to, you still have the medium voltage transmission system (which typically delivers electricity around metropolitan areas or suburbs). The MV system typically runs at voltages like 6.6, 11, 22 or 33kV.
This decision only impacts the LV section of this entire system, so realistically it is only the transformers that step down from MV to LV and systems that export power into the LV grid (like solar inverters) that are impacted.
As the post says – everywhere in Australia except WA is now 230V.
Different parts of the same grid can operate on different voltages because we use transformers (robots in disguise).
Here are the countries that use 230V:
Albania
Algeria
Andorra
Antigua and Barbuda
Armenia
Australia (except WA)
Austria
Azerbaijan
Bahrain
Belarus
Belgium
Bhutan
Bosnia and Herzegovina
Botswana
Brunei
Bulgaria
Cambodia
Congo, Republic of the
Côte d’Ivoire
Croatia
Czech Republic
Denmark
Dominica
Eritrea
Estonia
Faroe Islands
Finland
France
Gambia
Germany
Ghana
Greece
Grenada
Guadeloupe
Guernsey
Hungary
Iceland
India
Iraq
Ireland
Israel
Italy
Jersey
Jordan
Kosovo
Laos
Latvia
Liechtenstein
Lithuania
Luxembourg
Macau
Macedonia
Malawi
Malaysia
Maldives
Malta
Mauritius
Monaco
Montenegro
Myanmar
Nepal
Netherlands
New Zealand
Norway
Pakistan
Philippines
Poland
Portugal
Romania
Russia
Rwanda
Saint Pierre and Miquelon
Samoa
San Marino
Senegal
Serbia
Sierra Leone
Singapore
Slovakia
Slovenia
South Africa
Spain
Sri Lanka
St. Vincent and the Grenadines
Sudan
Swaziland
Sweden
Switzerland
Tanzania
Tunisia
Ukraine
United Kingdom
Uruguay
Yemen
Zambia
Finn – sorry – I missed the reference to WA, and it is highlighted. That is solely my error.
Moving from 240V to 230V makes sense to match Qld’s nominal voltage to Australian standards but a relaxation of the voltage RANGE from 12% to 16% is a retrograde step that won’t assist PV penetration.
1. With the 5% premises voltage drop allowed by AS3000, appliances will have to tolerate 204.7V to 253V. Energex’s AER submission (App 29) warned of 240V motors possibly overheating below 216V.
2. Appliance standards generally test safety at the max and not the min voltage.
3. Distributed energy resources are not the major source of high network voltages. Energex, for example, advised in their AER submission (App 29) that 76% of their distribution transformers are tapped too high. This is why many inverters trip on o/v.
4. PV penetration will be assisted if utilities fix their transformer taps and change tap plans to serve regular light load/peak generation periods instead of the infrequent peaks.
5. The notion that utilities will stick to a “preferred range of +6%/-2%” when they have not managed to conform to an existing regulated range will exacerbate an existing two tiered system; those with “good” volts and those with “bad”. A wider voltage range allows the utilities to better defend poor voltage performance.
Unfortunately it is not feasible for Energex to adjust all of their distribution transformer taps. They have over 40000 of these transformers, and around 30000 of them are tapped too high (actually, tapped at nominal, but because these transformers are mostly 0.433 kV or 0.415 kV, this is too high for the new 0.400 kV standard).
If they had to go around to all of these and adjust it would take far longer than the 27 October cutoff, and would cost a significant amount of money that would likely be passed onto the consumer.
Most likely the range will simply be achieved by increasing the range that the On-load tap changers will set the taps back at the zone and bulk substations. This will in effect allow the distribution voltage to lower (to say 10500 V instead of 11000). On a TX tapped at nominal and 0.433 kV on the LV this will result in an LV voltage of around 413 V or 238 V at the start of the LV run. Still high, but you have to remember some of the distribution transformers are 0.415 kV on their LV, and they will be at 396 V or 228 V. The LV typically is designed to run for a distance that allows 11 V drop – so the last few houses on the run will have 217 V if the transformer was 0.415.
This isn’t even considering that the 11 kV feeders also have a voltage drop, if embedded generation output isn’t exceeding load, so if the start of the feeder is at 10500 V the end may be at 10300 or even lower!
It’s a difficult juggling act and it will be interesting to see how it is handled.
If the network voltage is high, say 250V, Is it harder for your solar feed to enter the network and therefore does that reduce your solar feed?
It will start to reduce power over 250V as described here:
https://support.solarquotes.com.au/hc/en-us/articles/115001759153-My-Inverter-Keeps-Tripping-or-Reducing-Power-On-Over-voltage-What-can-I-do-
well our line is over 255 volts was wondering why our power bill was high , looks like we had not been exporting due to high network voltage so nothing has been offsetting the fish tank heater usage
we used to be a consistent 240v but lately noticed it was dropping to 230v when no sun avail
they might have to make it 220v during daytime ?