Dave, seen this? Grid overvoltage story in the Guardian

[Mr Purple]

https://www.theguardian.com/australia-news/2024/oct/19/could-australias-outdated-voltage-standards-be-taking-years-off-the-life-of-your-toaster

[tszaboo]

I wonder what appliance uses less energy with less voltage? SMPS will have higher efficiency. Space and water heaters will use the same, because they need to be on for longer to heat up. Motors will rotate at the same speed, and their consumption is mostly dependent on the load.

[mikeselectricstuff]

As mentioned above, a large proportion of loads will draw about the same total energy over a range of voltage, but at lower voltages, transmission losses will be higher, so I wonder if that would offset any gains from those appliances that draw less at lower voltages.

[tooki]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

[mikeselectricstuff]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

LED bulbs with capacitive droppers, vacuum cleaners, some motors in washing machines, ceiling fans, aircons & heaters that are run full blast so the thermostat never kicks in.

[coppice]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

I wonder what percentage of total electronic load on the grid is linear supplies in 2024?

[ejeffrey]

As mentioned above, a large proportion of loads will draw about the same total energy over a range of voltage, but at lower voltages, transmission losses will be higher, so I wonder if that would offset any gains from those appliances that draw less at lower voltages.

Presumably this would be accomplished by changing taps on neighborhood or individual customer transformers whenever they do service, not lowering the voltages on long distance transmission lines.  So the impact on transmission losses would be quite small either way.  Constant power devices would see their net transmission losses go slightly up, while resistive loads with thermostats would have losses go down slightly due to spreading the load out over more time.

[wraper]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

Any resistive stuff, such as space heater, kettle, toaster, clothes iron, hair drier.

[coppice]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

Any resistive stuff, such as space heater, kettle, toaster, clothes iron, hair drier.

most of that stuff just finishes the job faster, and takes no additional energy.

[wraper]

^Out of things I mentioned it's applicable to clothes irons and electric kettles. Some space heaters depending on room temperature.

[tooki]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

Any resistive stuff, such as space heater, kettle, toaster, clothes iron, hair drier.

Those will use less power, but the same energy because they need to run longer.

[tszaboo]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

I wonder what percentage of total electronic load on the grid is linear supplies in 2024?

I wonder how many MBAs working at the power company, giving interviews know the difference between power and energy.
Scary these are the same people that make decisions.
And even in the article, solar power baaad. Big bad. Except the voltage is somehow higher during the night.

[coppice]

I wonder how many MBAs working at the power company, giving interviews know the difference between power and energy.

When the EU set limits on power consumption for some appliances, like vacuum cleaners, it made some sense. Manufacturers had been competing with higher and higher power ratings, but using horribly inefficient motors. Sounds sensible. As soon as that was enacted they started talking about capping the power of things like kettles. Maybe their first effort just hit a sane target by luck. 

[TimFox]

In physics, we make a careful distinction between power, energy, strength, force, momentum, etc.
In normal English, these words are often considered synonymous.
A common problem when science encounters the general population.

[Whales]

^Out of things I mentioned it's applicable to clothes irons and electric kettles. Some space heaters depending on room temperature.

Clothes irons and electric kettles both have control loops, they heat until a threshold temp is hit.  Lowering their on-state power draw won't appreciable change their total energy draw (and in the case of a kettle may increase it, because more time is spend wasting heat to the environment).

[mikeselectricstuff]

As mentioned above, a large proportion of loads will draw about the same total energy over a range of voltage, but at lower voltages, transmission losses will be higher, so I wonder if that would offset any gains from those appliances that draw less at lower voltages.

Presumably this would be accomplished by changing taps on neighborhood or individual customer transformers whenever they do service, not lowering the voltages on long distance transmission lines.  So the impact on transmission losses would be quite small either way.  Constant power devices would see their net transmission losses go slightly up, while resistive loads with thermostats would have losses go down slightly due to spreading the load out over more time.

I'm talking about losses in the  cabling from the transformer to the house - relatively short distance, but a lot of it - no idea of the avarage  resistances involved.

[coppice]

^Out of things I mentioned it's applicable to clothes irons and electric kettles. Some space heaters depending on room temperature.

Clothes irons and electric kettles both have control loops, they heat until a threshold temp is hit.  Lowering their on-state power draw won't appreciable change their total energy draw (and in the case of a kettle may increase it, because more time is spend wasting heat to the environment).

To be more precise, only a small number of kettles - those which allow you to set a target temperature, heat the water, and hold it at that temperature - have control loops. Most kettles just cut out when the water boils. Either way, they only use the required energy. If they used more there would be a lot of steam peeling the decorations off the walls.

[tszaboo]

As mentioned above, a large proportion of loads will draw about the same total energy over a range of voltage, but at lower voltages, transmission losses will be higher, so I wonder if that would offset any gains from those appliances that draw less at lower voltages.

Presumably this would be accomplished by changing taps on neighborhood or individual customer transformers whenever they do service, not lowering the voltages on long distance transmission lines.  So the impact on transmission losses would be quite small either way.  Constant power devices would see their net transmission losses go slightly up, while resistive loads with thermostats would have losses go down slightly due to spreading the load out over more time.

I'm talking about losses in the  cabling from the transformer to the house - relatively short distance, but a lot of it - no idea of the avarage  resistances involved.

Typical grid impedance is 100-200mOhm. In your house, there are ~16 AWG wires for ~15m, which might double this ballpark.
So for 230V and 2300W ultra turbo non EU conform kettle, 10A, the losses are 20-40W. Let's say 1.5%.
If you reduce the voltage (no idea why but let's just entertain it) to 95% of it's nominal, then the current goes down to 95% and the losses go down 1-(0.95*0.95) -> 10%. Also known as 0.15% or the technical term I believe is f* all.

[wraper]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

Any resistive stuff, such as space heater, kettle, toaster, clothes iron, hair drier.

Those will use less power, but the same energy because they need to run longer.

Half of those are not even temperature controlled.

[Jeroen3]

What a weird article. They blame the voltage, but actually it's the at capacity last mile LV network. Most older network I'm, sure in AU also were laid out with a lower "typical household" load then today.

“If we drop the voltages back down to [the 230v standard], that creates an enormous amount of headroom” for more solar power exports, said Kuiper, who pressed for changes while at the Esb and since.

No, that's not how it works. Voltage is not a reflection of grid capacity. The bottlenecks can be upstream in MV or HV networks, then your LV voltage doesn't create capacity. The grid operator may even intentionally raise the LV network to curtail PV systems. As they do here in holland in some oudated regions.

[wraper]

What a weird article. They blame the voltage, but actually it's the at capacity last mile LV network. Most older network I'm, sure in AU also were laid out with a lower "typical household" load then today.

The issue is that although AU has 230V nominal instead of old 240V, all they did is put the new nominal number 230 V with high high side tolerance (+10% to -6%). So nothing changed in practice, but you're supposed to safely use 230V appliances.

[tooki]

I wonder what appliance uses less energy with less voltage?

Incandescent light bulbs I guess?

OK, in fairness, old gadgets with linear regulated power supplies would burn off more waste energy as heat with higher input voltages.

Any resistive stuff, such as space heater, kettle, toaster, clothes iron, hair drier.

Those will use less power, but the same energy because they need to run longer.

Half of those are not even temperature controlled.

Yes, they are. The only one of those that isn’t temperature controlled is the toaster — but the user will have to toast for longer to get the color they want. Similarly, if someone is using an old-fashioned hair dryer without temperature control, they’ll need to run it for longer.

[jonpaul]

IEC, NEC, UL and other utility spcs exist for the allowed limits on mains voltage.

Normally a PSU/SMPS/consumer device has a band of acceptable voltage areound a nominal.

https://www.power-sonic.com/blog/single-phase-and-three-phase-voltage-by-country/

In US the nominal was changed over the years 100>>110>117.

Tolerance band can be 8,10,12%.

Modern PSU topology includes a PFC that accepts any mains eg 70..260V and outputs a 360V DC bus with a boost PFC.

Jon

[tooki]

In US the nominal was changed over the years 100>>110>117.

Nominal was never 117V. That was a labeling compromise between 115V and 120V, the latter of which has been the nominal voltage for nearly a century. 

[Berni]

Yep this is pointless.

The biggest difference is for resistive heaters, yet most of those run on some form of thermostat.
So the only thing remaining is appliances with high power brushed motors like vacuum cleaners, angle grinders etc.. that will be slightly less powerful. This most certainly will not make a 100$ difference in your power bill, even if you love vacuuming your rugs daily.

Tho in general power companies try to keep the voltage cranked up because they are compensating for the voltage drop in the lines. They have a specified tolerance window of +x%/-x% so in order to have the best chance of staying in the window they crank it up on the high side so that more voltage drop can occur before it falls out of the bottom of the tolerance window. But the problem is the voltage drop is not always there during low load hours (also solar panels are becoming popular now) so you get the full voltage.

Peoples electronic devices die because the engineer that designed it was instructed by the company to make the PSU cheap and not last too long out of the warranty period. If not that then it is a brief overvoltage event (storm or some line fault) that pulls live to 500V for a moment is what kills it, not something that would be any less likely if the AC voltage was smaller.