Much of Australia has had a nominal voltage of 230 volts for single phase and 400 volts for three phase (120 degree systems) since the year 2000. Some states were late legislating the change, but it seems we are all ‘on board’ with this now.
The nominal voltage, and allowable supply and utilisation voltage ranges are specified in legislation in some states but are reliant on Australian Standard AS IEC 60038 Standard Voltages.
This standard not only covers off on low voltage systems but also details requirements for extra low voltage systems, medium voltage systems, including Single Wire Earth Return systems, and high voltage systems. The word ‘nominal’ basically means existing in name only. The nominal voltage is aptly named as rarely are voltage levels at the nominal value at the supply terminals and/or at appliances or other electrical equipment.
From 2000 up until 2022, the allowable supply range at the supply terminals was plus 10% above and minus 6% below 230 volts (other than states not legislated as such). The range is now plus or minus 10% which gives distribution network service providers (DNSPs) additional ‘room to move’.
In way of history, Australia ‘signed’ onto the rationalisation of nominal voltages and voltage ranges in 1983 with the introduction planned for the year 2000. The logic for this change, across the world, was to standardise the manufacture of electrical appliances worldwide. This meant that appliance manufacturers have had 41 years, up until 2024, to design, manufacture and supply appliances suited to the wider utilisation voltage range.
The change in the year 2000 meant little change for Australia on the top end of the allowable voltage range and little change on the lower end as many DNSPs went with minus 2% until the revised version of the standard was released in 2022. It would seem appropriate, given the 41 years, that DNSPs do move towards a wider supply voltage range.
I corresponded with the self-named ‘Volt Commissioner’ some years back as he expressed concerns that DNSPs deliberately deliver voltage levels towards the top end of the voltage range to increase revenue by increasing the kilowatt hours delivered. Whilst resistive appliances might draw higher levels of current, they will turn off quicker. Switch mode power supplies and induction motors are relatively unaffected as they are constant power users (though induction motor losses do increase as levels move away from their designed voltage). Additionally, in the early days of networks, voltage levels were supplied towards the top end of the utilisation range as low volts were considered more of an issue, particularly with heating and lighting appliances, than higher volts.
Today, the issue of managing network voltage levels is highly dependent on photovoltaic system penetration. This provides new challenges for DNSPs that they once didn’t need to deal with.
A quick look at some appliance nameplates shows how rationalisation of appliance manufacture worldwide has occurred e.g.
- Hisense TV Model: 75U7KAU – Nominal Voltage: 100V-240V AC. Frequency: 50Hz/60Hz. Wattage: 300W
- Dell Laptop Model: Precision 5570 – Nominal Voltage: 100-240V. Frequency: 50-60Hz. Wattage: 130W.
- Breville Blender Model: BBL820 SST – Nominal Voltage: 220-240V AC. Frequency: 50 Hz. Wattage: 1220W
- Breville Toaster Model: BTA735 BCVANZ – Nominal Voltage: 220-240V AC. Frequency: 50-60Hz. Wattage: 840-1000W
It can be seen that the TV and computer, both with switch mode power supplies, can ‘cope’ with a large voltage range at either of the standard frequencies. Also, their wattage is consistent regardless of the voltage or frequency. These appliances will even be suitable for the USA market with the 110 volt nominal supply system.
Additionally, the motorised blender has a consistent wattage regardless of the input voltage or what could also be called a consistent power user. The range of nominal voltage for this appliance is for countries that previously had a nominal voltage of 220 V, 230 V and 240 V.
Resistive appliances, such as the Breville toaster mentioned above, will have a range of wattages depending on the nominal voltage and more importantly, the actual wattage drawn will be dependent on the actual utilisation voltage supplied to the appliance. Resistive appliances will also operate more effectively and quicker at higher voltage levels.
AS 61000.3.100 Electromagnetic compatibility (EMC) – Limits – Steady state voltage limits in public electricity systems basically provides the methodology for logging of voltage levels to ensure compliance with the required supply and utilisation voltage ranges. This standard has not been updated since AS IEC 60038 was updated in 2022.
PowerLogic’s Power Quality Investigation Training Course helps trainees to manage the important issue of supply and utilisation voltage ranges, as well as the other important power quality parameters.