Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

No, we haven't lowered the voltage in the UK (although that may have
happened in places), we've just renamed it! Europe's voltage is
"standardised" on 230V. Other countries will have stayed on 220V, etc.
The idea is simply that equipment should be suitable for 230V + or - a
percentage and that will be okay at the low end of 220V supplies and the
high end of 240V supplies - simply so that different equipment isn't
required in different countries throughout Europe.

SteveW

On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

230v, with tolerances that allow all EU countries to keep exactly what
they had before, but to claim that they are now harmonised.

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

+/- 1% IIRC

Colin Bignell

Jethro wrote:

Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

No - 245 is normal. I have 241V here typically.

Remember - "they" did not reduce the voltage, "they" declared our nominal
voltage to be lower whilst upping the tolerances.

Because manufacturers work to the nominal but allow for the tolerances it
mostly works well enough, except for things like filament lamps that tend to
blow faster than they used to when they were designed for our *actual*
nominal voltage.


From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

"UK nominal supply voltage to 230V with a permitted voltage tolerance of
+10% -6%. In practice it's still 240V, but is allowed to vary by a greater
percentage."

and

"National Grid has a licence obligation to control frequency within the
limits specified in the 'Electricity Supply Regulations', i.e. ±1% of
nominal system frequency (50.00Hz) save in abnormal or exceptional
circumstances."

from

http://www.btinternet.com/~fynevue/bankside/cegb1.html

and



--
Tim Watts

On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

Not much...


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:

On 17/11/2011 18:00, Jethro wrote:

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

Not much...

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

On Fri, 18 Nov 2011 07:51:55 +0000, Andy Burns wrote:

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I believe so not that there are many mains locked clocks these days.
I think one would have to define "day" as well, I doubt it is say
midnight to midnight but could be any 24hr rolling period.

--
Cheers
Dave.

On Nov 18, 7:51*am, Andy Burns wrote:
John Rumm wrote:
On 17/11/2011 18:00, Jethro wrote:

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

Not much...

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I dont think they have for decades. Synchronous clocks and alarms are
history now, but still lots of synchronous timers in use.


NT

On Fri, 18 Nov 2011 00:12:21 -0800 (PST), NT wrote:

Do they still adjust the total number of mains cycles to be
exactly
4,320,000 per day?

I dont think they have for decades.

I have a vague memory of them asking permission to make a time
adjustment after the Sizewell B/Longannet incident, though with most
of the generation still running I can't see the real need, prehaps
they didn't in the end.

--
Cheers
Dave.

On 17/11/11 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

We didn't do anything. We always provided 240V in the UK

Parts of Europe always provided 220V or 230V.

We have standardised on 230V +10% -6%

Nothing actually changed, it just means that anything from 216.2V to 253V is
within tolerance. We carry on supplying 240V and other countries carry on
supplying 220V/230V. I have seen up to 252V on my supply (as reported by a
UPS) before.



From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

Andy Burns wrote:
John Rumm wrote:

On 17/11/2011 18:00, Jethro wrote:

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

Not much...

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

Yes.

NT wrote:
On Nov 18, 7:51 am, Andy Burns wrote:
John Rumm wrote:
On 17/11/2011 18:00, Jethro wrote:
From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....
Not much...
Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I dont think they have for decades. Synchronous clocks and alarms are
history now, but still lots of synchronous timers in use.


NT

I think you will find that they do...

Dave Liquorice wrote:
On Fri, 18 Nov 2011 00:12:21 -0800 (PST), NT wrote:

Do they still adjust the total number of mains cycles to be
exactly
4,320,000 per day?
I dont think they have for decades.

I have a vague memory of them asking permission to make a time
adjustment after the Sizewell B/Longannet incident, though with most
of the generation still running I can't see the real need, prehaps
they didn't in the end.

I think they need to tell people they have been down for a period..and
seek permission to go over the frequency upwards to catch up;


normally its quite easy to catch up overnight.

In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

I live in at the end of a cul-de-sac in a small country village.

Until a year or two ago, whenever I had occasion to measure my mains
voltage, it was obviously meant to be a nominal 240V. In fact, I recall
that 242V was pretty typical reading, with somewhat over 250V being
reached on various occasions.

However, a year ago, an old works colleague died, and I acquired some of
his electronic bits and pieces - one of which was a home-made
purpose-built meter for measuring the mains voltage (the display being a
large 1mA meter in a box - ie simple, but effective). I checked the
calibration against a couple of 'professional' digital multimeters, and
made sure that the reading was 'spot-on' at around 230V.

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?







--
Ian

Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

IIRC, most, if not all, substations have either remote controlled or
automatic tap changing, so if the voltage gets near the end of the
acceptable range at the substation, it can be adjusted. If you're close
to the substation, you should get pretty good stability, but if you're
at the wrong end of a longish line, then your voltage will vary
according to what you and the neighboours have got turned on at the time.

It has also been known for the voltage to be reduced under conditions of
heavy demand to help reduce the load.

--
Tciao for Now!

John.

In message , John Williamson
writes
Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's
cold spell, it did drop to 214V, but it is rarely below 225V - and I
can recall seeing it above 231-ishV. All I can think is that the
sub-station transformer has various output taps, and at some time, it
changed from 240V to 230V.
Is this likely to be an unusual situation, or will it be normal
practice to drop the voltage when an opportunity arises (say, during
maintenance visits etc)?

IIRC, most, if not all, substations have either remote controlled or
automatic tap changing, so if the voltage gets near the end of the
acceptable range at the substation, it can be adjusted. If you're close
to the substation, you should get pretty good stability, but if you're
at the wrong end of a longish line, then your voltage will vary
according to what you and the neighboours have got turned on at the time.

It has also been known for the voltage to be reduced under conditions
of heavy demand to help reduce the load.

Of course, the "can" in "I can recall seeing it above 231-ishV" should
have been "can't".

But if the domestic voltage can be easily change to 230V (which mine now
seems to be), is this likely to be a general policy (even if it's on a
'when we get around to it' basis)? Mine has certainly changed, and I'm
pretty sure that it's not because of additional local loading. The
actual voltage is actually pretty stable - rarely falling below 225V,
and I've never seen it above 231V - which I don't think would be the
case if unexpected heavy loading was happening.
--
Ian

On Fri, 18 Nov 2011 08:04:10 +0000 (GMT), "Dave Liquorice"
wrote:

On Fri, 18 Nov 2011 07:51:55 +0000, Andy Burns wrote:

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I believe so not that there are many mains locked clocks these days.
I think one would have to define "day" as well, I doubt it is say
midnight to midnight

Then you are right

but could be any 24hr rolling period.

It is. They constantly have a display of real time derived from the
NPL transmitter at Anthorn in Cumbria and system time driven by the
mains, and a display of the difference (in minutes and seconds)


--

In message , The Other Mike
writes
On Fri, 18 Nov 2011 08:04:10 +0000 (GMT), "Dave Liquorice"
wrote:

On Fri, 18 Nov 2011 07:51:55 +0000, Andy Burns wrote:

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I believe so not that there are many mains locked clocks these days.
I think one would have to define "day" as well, I doubt it is say
midnight to midnight

Then you are right

but could be any 24hr rolling period.

It is. They constantly have a display of real time derived from the
NPL transmitter at Anthorn in Cumbria and system time driven by the
mains, and a display of the difference (in minutes and seconds)

It may not be now, but wasn't it 'traditionally' 8am (the start of the
working day)?
--
Ian

Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V.

You're using "nominal" wrong. Nominal is what it is named/declared
to be, not what it actually is. The nominal voltage is 230v-6%+10%.
What you have been measuring is the measured voltage.

JGH

In article , Jethro
writes

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

http://www.dynamicdemand.co.uk/grid.htm

--
(\__/)
(='.'=)
(")_(")

In message
,
jgharston writes
Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V.

You're using "nominal" wrong. Nominal is what it is named/declared
to be, not what it actually is. The nominal voltage is 230v-6%+10%.
What you have been measuring is the measured voltage.

I was (obviously) using the loose, non-technical 'nominal'. However, in
this case, these days, the actual voltage is almost always pretty close
to nominal. The lowest I've ever seen (214V when the supply was
understandably struggling a bit) is a smidgen out-of-spec (-6% =
216.2V). Mustn't grumble, I suppose).

Actually, I've just plugged in my ex-colleague's meter again, and I see
it's nearly 235V. Previously, it's never exceeded 231V. Could it be,
that at the power stations, even though the weather is unusually mild,
they are making absolutely sure that they use up their allocated stocks
of coal?
--
Ian

Ian Jackson wrote:
In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

I live in at the end of a cul-de-sac in a small country village.

Until a year or two ago, whenever I had occasion to measure my mains
voltage, it was obviously meant to be a nominal 240V. In fact, I recall
that 242V was pretty typical reading, with somewhat over 250V being
reached on various occasions.

However, a year ago, an old works colleague died, and I acquired some of
his electronic bits and pieces - one of which was a home-made
purpose-built meter for measuring the mains voltage (the display being a
large 1mA meter in a box - ie simple, but effective). I checked the
calibration against a couple of 'professional' digital multimeters, and
made sure that the reading was 'spot-on' at around 230V.

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?


yes..the actual voltage SHOULD be around 230v but for legacy reasons its
quite broad.

They will up the tap if a lot of power is being drawn..but some
isntallations don't have taps..

Ian Jackson wrote:
In message
,
jgharston writes
Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V.

You're using "nominal" wrong. Nominal is what it is named/declared
to be, not what it actually is. The nominal voltage is 230v-6%+10%.
What you have been measuring is the measured voltage.

I was (obviously) using the loose, non-technical 'nominal'. However, in
this case, these days, the actual voltage is almost always pretty close
to nominal. The lowest I've ever seen (214V when the supply was
understandably struggling a bit) is a smidgen out-of-spec (-6% =
216.2V). Mustn't grumble, I suppose).

Actually, I've just plugged in my ex-colleague's meter again, and I see
it's nearly 235V. Previously, it's never exceeded 231V. Could it be,
that at the power stations, even though the weather is unusually mild,
they are making absolutely sure that they use up their allocated stocks
of coal?

well yes and no,, they are doing that, but mostly the power is being
exported to the continent where unremitting Green policies seem to have
resulted in a general shortfall.

What we are seeing though is a bit more voltage and frequency
instability - the fast response balancer is Dinorwig, and I've seen that
running flat out recently. That means they have to try and baalnce with
CCGT - the coal stations CAN balance but take a significant period to
ramp up and down.

Ian Jackson wrote:
In message , John Williamson
writes
Ian Jackson wrote:
Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's
cold spell, it did drop to 214V, but it is rarely below 225V - and I
can recall seeing it above 231-ishV. All I can think is that the
sub-station transformer has various output taps, and at some time, it
changed from 240V to 230V.
Is this likely to be an unusual situation, or will it be normal
practice to drop the voltage when an opportunity arises (say, during
maintenance visits etc)?

IIRC, most, if not all, substations have either remote controlled or
automatic tap changing, so if the voltage gets near the end of the
acceptable range at the substation, it can be adjusted. If you're
close to the substation, you should get pretty good stability, but if
you're at the wrong end of a longish line, then your voltage will vary
according to what you and the neighboours have got turned on at the time.

It has also been known for the voltage to be reduced under conditions
of heavy demand to help reduce the load.

Of course, the "can" in "I can recall seeing it above 231-ishV" should
have been "can't".

But if the domestic voltage can be easily change to 230V (which mine now
seems to be), is this likely to be a general policy (even if it's on a
'when we get around to it' basis)? Mine has certainly changed

Mine's been high for years, a few months ago they turned to do some work
on the substation at the top of the road, a BFO artic sized diesel
generator arrived and thundered away for about 6 hours while they "did
something".

When the work was complete I made a point of checking the before and
after voltages from my UPS, thinking they might have adjusted the taps
as part of the work ... still fluctuates between 249 and 254 over the
course of a day.

On Fri, 18 Nov 2011 15:30:19 +0000, Ian Jackson
wrote:

In message , The Other Mike
writes
On Fri, 18 Nov 2011 08:04:10 +0000 (GMT), "Dave Liquorice"
wrote:

On Fri, 18 Nov 2011 07:51:55 +0000, Andy Burns wrote:

Do they still adjust the total number of mains cycles to be exactly
4,320,000 per day?

I believe so not that there are many mains locked clocks these days.
I think one would have to define "day" as well, I doubt it is say
midnight to midnight

Then you are right

but could be any 24hr rolling period.

It is. They constantly have a display of real time derived from the
NPL transmitter at Anthorn in Cumbria and system time driven by the
mains, and a display of the difference (in minutes and seconds)

It may not be now, but wasn't it 'traditionally' 8am (the start of the
working day)?

That might have been an aim, but mainly as a result of when it was
feasible to do most of the catching up - overnight, with lower loads
and an excess of generation.

10 seconds error needing to be corrected over 8 hours only needs 500
cycles extra , or a couple of 10ths of a hertz above 50 to catch up.
That equates to running all the 2 pole generators at a bit over 3001
rpm rather than 3000, it takes a bit more fuel, but is trivial to
achieve.


--

On Fri, 18 Nov 2011 18:30:16 +0000, Andy Burns wrote:

... still fluctuates between 249 and 254 over the course of a day.

I bet you get through incandescant light bulbs at a fair rate if you
stil have any. Out voltage was at a similar level and we'd havea bulb
blow every week or so. Got a UPS, it wenet straight into voltage
reduction mode... looked at it's measured voltage and rang the DNO.
They came round within two hours, measured agreed and cam back pretty
quickly to adjust the tapping on our (it only feeds us) transformer.
We now sit between 240 and 245 most of the time and bulbs last
noticeably longer.

--
Cheers
Dave.

Dave Liquorice wrote:

On Fri, 18 Nov 2011 18:30:16 +0000, Andy Burns wrote:

... still fluctuates between 249 and 254 over the course of a day.

I bet you get through incandescant light bulbs at a fair rate if you
stil have any.

Only two rooms have filaments (both mains halogens now) replaced all the
others with CFLs the day I moved in (back then CFLs were expensive
enough that I did bring them with me).

Got a UPS, it wenet straight into voltage
reduction mode...

Mine usually goes into "trim" mode once per day, then often at around
midnight it flips into full "on battery" mode for about 10 seconds.

On 18 Nov,
Ian Jackson wrote:

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

I have lived in my current house for over 30 years.

Ever since we moved in the voltage has averaged about 230volts. At peak times
nearer 220 volts. This used to cause problems with TV picture size, but with
modern sets no longer a problem. However, at peak times lights seem dim.
Overnight it may rise to slightly over 240.

I put it down to a cheapskate builder, and the remoteness of the sub-station.
I haven't noticed it out of the old(+-6%) or the new spec.

At our previous house we were constantly over 240v, often over 250 (almost
next door to the sub-station) bulbs would last weeks rather than years!

I very much doubt if your taps have been changed.

--
B Thumbs
Change lycos to yahoo to reply

On 18/11/2011 12:38, Ian Jackson wrote:
In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

It sounds like your supply has been moved down a tap, or the loading
conditions elsewhere on your phase have changed.

I am not aware of any policy to transition distribution to 230V though.


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

In message , John
Rumm writes
On 18/11/2011 12:38, Ian Jackson wrote:
In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

It sounds like your supply has been moved down a tap, or the loading
conditions elsewhere on your phase have changed.

I am not aware of any policy to transition distribution to 230V though.

I think I'll have to amend my claim that, recently, my mains voltage had
never risen above 231V (although this was certainly the case from
January (when I first acquired the home-made meter) until September.
However, as a result of me doing a bit of tidying up, and it's been
unplugged for the last two months.

As a result of this thread, I plugged the meter in again. Yesterday
evening, it was around 228V. But, later on, it rose to 235V, and it's
still there this morning. [I'll check the reading on a 'proper' meter.]
However, I suppose it's just possible that they might have tweaked the
voltage up a notch.
--
Ian

On Sat, 19 Nov 2011 08:33:43 +0000, Ian Jackson
wrote:

In message , John
Rumm writes
On 18/11/2011 12:38, Ian Jackson wrote:
In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

It sounds like your supply has been moved down a tap, or the loading
conditions elsewhere on your phase have changed.

I am not aware of any policy to transition distribution to 230V though.

I think I'll have to amend my claim that, recently, my mains voltage had
never risen above 231V (although this was certainly the case from
January (when I first acquired the home-made meter) until September.
However, as a result of me doing a bit of tidying up, and it's been
unplugged for the last two months.

As a result of this thread, I plugged the meter in again. Yesterday
evening, it was around 228V. But, later on, it rose to 235V, and it's
still there this morning. [I'll check the reading on a 'proper' meter.]
However, I suppose it's just possible that they might have tweaked the
voltage up a notch.

When I lived in the wilds of remote Cambridgeshire, my electrickery
went through a phase (sorry!) of peaking at around 190v, measured with
an analogue multimeter). When it got to a stage where some things were
just not working properly, I called the electricity company and on
investigation they found a corroded connection in the miles of cable
that came over the fields to my house. After they fixed that, I got
240v with hardly any variation. I don't suppose that could be relevant
to your experience, could it?

Nick

In message , Mike Tomlinson
writes
In article , Jethro
writes

From my vague recollection of a visit to CEGBs London operations, the
closer the frequency is to 50Hz, the better the grid is coping with
demand. But I can't remember how much they let it drift ....

http://www.dynamicdemand.co.uk/grid.htm

http://www.gridwatch.templar.co.uk gives the level of demand and the
types of generation too.

--
Goalie of the Century

In message , Nick Odell
writes
On Sat, 19 Nov 2011 08:33:43 +0000, Ian Jackson
wrote:

In message , John
Rumm writes
On 18/11/2011 12:38, Ian Jackson wrote:
In message , John
Rumm writes
On 17/11/2011 18:00, Jethro wrote:
Finally got my acquired (from office closure) UPS working under Linux,
and it's showing :


UPS Model:Not supported
Status: ONLINE
UPS temp:25.0 °C
Battery:13.50 V
Input: 245.0 V
49.9 Hz
Output: 244.5 V

with a loading of 13% (one PC, 3 USB drives)

is it me or is 245 quite high for a UK reading, I thought we had reduced
to 220 ?

Nope, 245 is quite normal. The UK is still 240V generally, all that
changed was the allowable range in the spec (which is 230V -6%/+10%)

Since then, I have had it connected most of the time, and it seems
obvious that the nominal voltage is now 230V. During last winter's cold
spell, it did drop to 214V, but it is rarely below 225V - and I can
recall seeing it above 231-ishV. All I can think is that the sub-station
transformer has various output taps, and at some time, it has been
changed from 240V to 230V.

Is this likely to be an unusual situation, or will it be normal practice
to drop the voltage when an opportunity arises (say, during maintenance
visits etc)?

It sounds like your supply has been moved down a tap, or the loading
conditions elsewhere on your phase have changed.

I am not aware of any policy to transition distribution to 230V though.

I think I'll have to amend my claim that, recently, my mains voltage had
never risen above 231V (although this was certainly the case from
January (when I first acquired the home-made meter) until September.
However, as a result of me doing a bit of tidying up, and it's been
unplugged for the last two months.

As a result of this thread, I plugged the meter in again. Yesterday
evening, it was around 228V. But, later on, it rose to 235V, and it's
still there this morning. [I'll check the reading on a 'proper' meter.]
However, I suppose it's just possible that they might have tweaked the
voltage up a notch.

When I lived in the wilds of remote Cambridgeshire, my electrickery
went through a phase (sorry!) of peaking at around 190v, measured with
an analogue multimeter). When it got to a stage where some things were
just not working properly, I called the electricity company and on
investigation they found a corroded connection in the miles of cable
that came over the fields to my house. After they fixed that, I got
240v with hardly any variation. I don't suppose that could be relevant
to your experience, could it?

Anything is possible, but I can't really say I have a problem. It's been
sitting at a steady 235V all afternoon, but I now (5.30pm) I see it has
now dropped to a somewhat 'wavery' 225V (occasionally kicking up and
down by a couple of volts). Can't really complain about that! Having
finished my tidying up, I'll now leave the meter plugged in, and keep an
occasional eye on it again.
--
Ian

In article , Goalie of the Century
writes

http://www.gridwatch.templar.co.uk gives the level of demand and the
types of generation too.

Many thanks. I know TNP had been working on something but hadn't
spotted the url.

--
(\__/)
(='.'=)
(")_(")