Author Topic: Mains voltage poll (UK)  (Read 4807 times)

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Online bd139

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Re: Mains voltage poll (UK)
« Reply #25 on: November 22, 2017, 10:09:04 am »
245.0 here in London 10:00. Calibrated Keysight U1241C. Residential ring main. Unloaded.
 

Offline NivagSwerdna

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Re: Mains voltage poll (UK)
« Reply #26 on: November 22, 2017, 10:17:08 am »
Isn't this all a bit pointless?  Doesn't it depend on the load across the wire when you measure it?  For me wouldn't that be dependent on the resistance of the wire back to substation and all loads down my street in parallel with that phase?
 

Online bd139

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Re: Mains voltage poll (UK)
« Reply #27 on: November 22, 2017, 10:19:04 am »
Yes and no. Sometimes there are persistent drops and peaks. We get up to 300v here occasionally which causes some problems (I've lost about 20 wall warts in the last few years)
 

Offline Bashstreet

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Re: Mains voltage poll (UK)
« Reply #28 on: November 22, 2017, 10:57:52 am »
Quite few countries in U.K  :-DD
 

Online IanB

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Re: Mains voltage poll (UK)
« Reply #29 on: November 22, 2017, 10:59:40 am »
Isn't this all a bit pointless?  Doesn't it depend on the load across the wire when you measure it?  For me wouldn't that be dependent on the resistance of the wire back to substation and all loads down my street in parallel with that phase?

It's interesting actually to see what kind of variation in the nominal service voltage might be seen at different places and times.

But mostly for me it does confirm that the nominal voltage in the UK is still 240 as it always has been.
« Last Edit: November 22, 2017, 11:01:30 am by IanB »
I'm not an EE--what am I doing here?
 

Offline Avacee

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Re: Mains voltage poll (UK)
« Reply #30 on: November 22, 2017, 11:26:42 am »
For the OP:  243.7V @ 49.7Hz at 20:32 UK time in the North-west

Wow, that frequency has a huge deviation from the nominal frequency.
What kind of instrument did you use?

Because according to this website that shows the actual powergrid frequency, it is generally much more accurate:

http://www.mainsfrequency.com/
UT139C - freq spec is 10Hz-10MHz ±(0.1%+4)   .. Obviously I'll take the official figure over a cheapo UT any day :)
Currently it's 243.9V at 49.97Hz.

Though it's not uncommon for the network to sag across the UK on the hour or half-hour in the evening due to https://en.wikipedia.org/wiki/TV_pickup

« Last Edit: November 22, 2017, 11:29:50 am by Avacee »
 
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Offline mariush

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Re: Mains voltage poll (UK)
« Reply #31 on: November 22, 2017, 12:00:32 pm »
Romania ... 1:22 am , 246v AC (using a kill-a-watt type device) 

Typical for this hour...

AFAIK it's 230v +10%, -6% ... so still within acceptable limits.

Do you know what your local voltage is supposed to be (nominal value)? Even though 246 V is within +10% of 230 V, I think voltage regulation at the point of distribution is usually better than that (see above for examples of voltage regulation in the UK). I suspect voltage regulation is better in the center of towns and cities, but may be worse in rural areas especially at the end of a long spur.

It's 234v AC now at 14:00 

Yes, I live relatively far from the center of the town but it's a populated area, so it's not like the quality would be worse due to lower population density.

The voltage is just not as regulated here... i had an cheap atx power supply without power factor correction die on me a couple months ago when the voltage got up to 249v AC
The frequency however is pretty much rock solid... 50 Hz or maybe 49.9 Hz for a few seconds  at most.
 

Offline Zero999

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Re: Mains voltage poll (UK)
« Reply #32 on: November 22, 2017, 04:34:19 pm »
Bedford, UK: 240.4V, 50.06Hz.
 

Online Mr. Scram

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Re: Mains voltage poll (UK)
« Reply #33 on: November 22, 2017, 05:17:56 pm »
Wow, that's some variation. Do you live in a third world country?  ;D
In regard to anything networked, it almost seems those down under are.
 

Offline Cyberdragon

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Re: Mains voltage poll (UK)
« Reply #34 on: November 22, 2017, 05:43:37 pm »
Now everyone measure their distortion! >:D
*BZZZZZZAAAAAP*
Voltamort strikes again!
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Offline Simon

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Re: Mains voltage poll (UK)
« Reply #35 on: November 22, 2017, 05:59:44 pm »
Sure YOUR mains voltage will be determined by whatever your local substation supplies you (mine is in my back garden - well ok that bit of land is not mine but it cuts into my land). It's more relevant for the range devices can work in. Uk is 240, europe is 220, 230 is in the middle and well within a 5% tolerance of both (208.5/241.5V)
 

Offline SeanB

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Re: Mains voltage poll (UK)
« Reply #36 on: November 22, 2017, 06:09:10 pm »
South Africa earlier the week measured 238VAC, typical for the area, as I can see the 500kVA transformer across the park, though the PISWA cable does follow the street down and back, making it 200m or so of the Victorian era copper ( and 20m of more modern cable scotchcast to it where the cable thieves nicked it) that used to power trolley bus power. End of the line by me, there is a power monitor in the meter room, power line info sent from the PLC, that does monitoring for the Metro. Highest voltage I saw was 278VAC, when the neutral and PE cores were nicked by the thieves, quickly went down and pulled the big red switch on the meter room to keep the block safe, then got on the phone to tell Metro the cable had been nicked again. Too bad for the corner coffee shop, his brewing equipment and IT stuff, plus all the lighting, were on the phases not connected to the heaviest load from the stoves, and they all lost that battle in a blaze of glory.
 

Offline Berni

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Re: Mains voltage poll (UK)
« Reply #37 on: November 22, 2017, 06:44:09 pm »
Now everyone measure their distortion! >:D

Queue the exploding scope probes!

Nah i got a Keithley 2015 DMM here so it can give me THD directly.
 

Offline Retep

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Re: Mains voltage poll (UK)
« Reply #38 on: November 22, 2017, 07:23:48 pm »
230VAC +10%/-6% 50Hz is imposed by the bureaucrats in Brussels, however in little over a year from now the UK is no longer part of the EU and is finally free to choose its own mains voltage and frequency.
 

Online bd139

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Re: Mains voltage poll (UK)
« Reply #39 on: November 22, 2017, 07:34:55 pm »
We’ll be going back to 230/415V three wire DC then.
« Last Edit: November 22, 2017, 07:36:40 pm by bd139 »
 

Online IanB

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Re: Mains voltage poll (UK)
« Reply #40 on: November 22, 2017, 07:51:38 pm »
Sure YOUR mains voltage will be determined by whatever your local substation supplies you (mine is in my back garden - well ok that bit of land is not mine but it cuts into my land).

That's the whole point of the survey actually. It's possible some people might have seen 230 V and some people 240 V depending on the age of their property. But everyone's answers seem to indicate that the UK is still on 240 V.
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Offline rstofer

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Re: Mains voltage poll (UK)
« Reply #41 on: November 22, 2017, 07:56:15 pm »
It's a funny story in the US, at least from my perspective.

We are officially supposed to be 120VAC, 60hz, but depending on who you ask, some people will say the US is 115V, 110V. There are all tolerances, and these numbers are still within them, but all my meters (on a UPS for example) stay right around 120VAC.


A long time ago, the standard was 110V.  Then it was raised to 115 then 117 and finally 120V.  You can find schematics with each of these values depending on when they were published.  This article doesn't mention 117V but apparently 120V was standardized in 1984 (fairly recent).

https://www.quora.com/Is-the-power-system-in-the-US-technically-110-115-or-120VAC-How-about-220-or-is-it-240-or-235VAC

The line-to-line voltage will be double or 240V.

 

Offline Retep

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Re: Mains voltage poll (UK)
« Reply #42 on: November 22, 2017, 09:07:12 pm »
We’ll be going back to 230/415V three wire DC then.
Sounds like an excellent choice to me.
 

Offline tooki

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Re: Mains voltage poll (UK)
« Reply #43 on: November 24, 2017, 03:59:11 pm »
I normally see high 240s.

The "harmonisation" was purely political, not a single voltage regulator or transformer tap was changed.

All countries used to have tolerances od +/- 6%. 240v countries "harmonised" to 230 +10% / -6%. 220v countries "harmonised" to 230 -10% / +6%.

Do the maths, and you will see that to allowable voltage ranges are (almost) completely unchanged.

Genius!

Sure YOUR mains voltage will be determined by whatever your local substation supplies you (mine is in my back garden - well ok that bit of land is not mine but it cuts into my land). It's more relevant for the range devices can work in. Uk is 240, europe is 220, 230 is in the middle and well within a 5% tolerance of both (208.5/241.5V)
No, Europe is not nominal 220V, and hasn’t been since 1983! It’s nominal 230V, with stepwise change in the acceptable tolerances. Given the actual voltages reported (and the ease with which a power generator’s output voltage can be changed, given that it must be adjusted constantly during use to adapt to load), I don’t think there’s a shred of evidence that the actual voltages in Europe have remained unchanged, by virtue of simply still falling within tolerance.
 

Offline A Hellene

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Re: Mains voltage poll (UK)
« Reply #44 on: November 24, 2017, 04:29:53 pm »
Last year I personally calibrated my APC SURT 1000 XLi UPS:


APC SURT 1000 XLi report.png

And, no, I do not think that this kind of everyday mains voltage fluctuations is an exclusive Hellenic consumer's privilege!


-George

<EDIT>: Damn the browser auto-correction feature!...
« Last Edit: November 24, 2017, 05:15:04 pm by A Hellene »
Hi! This is George; and I am three and a half years old!
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Offline Delta

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Re: Mains voltage poll (UK)
« Reply #45 on: November 24, 2017, 11:48:43 pm »
I normally see high 240s.

The "harmonisation" was purely political, not a single voltage regulator or transformer tap was changed.

All countries used to have tolerances od +/- 6%. 240v countries "harmonised" to 230 +10% / -6%. 220v countries "harmonised" to 230 -10% / +6%.

Do the maths, and you will see that to allowable voltage ranges are (almost) completely unchanged.

Genius!

Sure YOUR mains voltage will be determined by whatever your local substation supplies you (mine is in my back garden - well ok that bit of land is not mine but it cuts into my land). It's more relevant for the range devices can work in. Uk is 240, europe is 220, 230 is in the middle and well within a 5% tolerance of both (208.5/241.5V)
No, Europe is not nominal 220V, and hasn’t been since 1983! It’s nominal 230V, with stepwise change in the acceptable tolerances. Given the actual voltages reported (and the ease with which a power generator’s output voltage can be changed, given that it must be adjusted constantly during use to adapt to load), I don’t think there’s a shred of evidence that the actual voltages in Europe have remained unchanged, by virtue of simply still falling within tolerance.

Fair enough, I should have been clearer, no voltage control changes were made to the generation or distribution network here in the UK.  We are still on 240 nominal in practice.

I have never measured less than 238v at peak demand time.  If the grid operators were consciously trying to aim for 230 nominal, they are doing a bloody bad job of it.


I cannot speak about other countries.
 

Online IanB

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Re: Mains voltage poll (UK)
« Reply #46 on: November 24, 2017, 11:55:32 pm »
Fair enough, I should have been clearer, no voltage control changes were made to the generation or distribution network here in the UK.  We are still on 240 nominal in practice.

I have never measured less than 238v at peak demand time.  If the grid operators were consciously trying to aim for 230 nominal, they are doing a bloody bad job of it.

Which is why I wanted to do a quick straw poll, to confirm this. Simon didn't actually post his local mains voltage, in spite of being just a few feet away from the substation. It would be interesting to see what allowance they make for voltage drop in the low voltage cable to the most remote consumers. Simon is presumably going to get a voltage pretty close to what comes out of the substation.
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Offline HKJ

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Re: Mains voltage poll (UK)
« Reply #47 on: November 25, 2017, 09:17:37 am »
I got a bit interested in how exactly the mains voltage varies around here and not just a quick glance on my power analyzer now and then. This means I put my DMM7510 on it for a bit over a day.


First curve is logged with one second intervals, the voltage has a lot of fast changes.


Calculating a rolling 1 minute average gets rid of some of the changes.


10 minute average


1 hour average

I live in a apartment in Copenhagen Denmark, i.e. in a big city.
« Last Edit: November 25, 2017, 09:19:43 am by HKJ »
 

Offline Rerouter

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Re: Mains voltage poll (UK)
« Reply #48 on: November 25, 2017, 09:27:38 am »
Sydney Aus, at 20:20 late evening, 243.6V AC, at 13:00 It was holding steady at 264V from all the nearby solar installations.
 

Online tggzzz

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Re: Mains voltage poll (UK)
« Reply #49 on: November 25, 2017, 10:45:22 am »
Edit: Next time an enviromentalist tells me we should close all nuclear plants and build more solar I'm going to give them a link to the sites above and ask them how much solar has produced in the last week (the weather has been pretty shitty).

Indeed, but the wind is always blowing somewhere, isn't it?

No. Not when there is a high pressure blocking zone sat over the UK for days at a time.

Using a year's worth of gridwatch data, a rule of thumb was that if the UK peak wind power output is P, then it is less that x*P (0 in range 0..100%) for x% of the time. For example, 10% of the time it is less than 10% of peak.

You need reliable baseload power stations active and ready to generate when, not if, they are needed. The cost of keeping those stations available should be included in the wind/solar costs.
There are lies, damned lies, statistics - and ADC/DAC specs.
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