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Old 30th Mar 2018, 1:56 pm   #121
G6Tanuki
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Default Re: Electric clocks running slow warning

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Originally Posted by The Philpott View Post
My bedside LED clock radios have lost a minute since we went to BST, but i don't know if they rely on frequency.
My nearly-20-year-old Sony "Dream Machine" bedside clock-radio automatically syncs its clock to the radio RDS time-signal. Which is kinda handy given that its internal timekeeping battery-backup has long since ceased to back-up and we get lots of mains power-outages here.

[Strangely, power-outages don't cause the radio's presets to lose their presettedness though!]
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Old 30th Mar 2018, 1:57 pm   #122
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Default Re: Electric clocks running slow warning

Microwave ovens probably don't worry about mains frequency, but mains voltage might affect them. It may be that some modern ones use a capacitive dropper to supply the control circuitry so if this has lost some capacitance then things may become marginal when the supply voltage is low.
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Old 30th Mar 2018, 1:57 pm   #123
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Default Re: Electric clocks running slow warning

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Originally Posted by kalee20 View Post
Can you not ask your electricity provider? They should be able to provide an answer.
Hi.

I was hoping one of the experts on this forum may know the answer.

Regards
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Old 30th Mar 2018, 1:59 pm   #124
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Default Re: Electric clocks running slow warning

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Originally Posted by G8HQP Dave View Post
Microwave ovens probably don't worry about mains frequency, but mains voltage might affect them.
OK thanks for confirming that.

Regards
Symon.
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Old 30th Mar 2018, 2:09 pm   #125
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Default Re: Electric clocks running slow warning

I had some 'slow clocks' correspondence on Twitter with power station @Draxnews. They professed to know nothing of the UK low frequency problem, though they had featured the continental problem in an earlier news release.

This is disturbing because the massive potential 4GW output of Drax must alone be capable of influencing the grid frequency, given a little more steam input to their turbines.

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Old 30th Mar 2018, 2:23 pm   #126
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Default Re: Electric clocks running slow warning

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Quote:
Originally Posted by G8HQP Dave View Post
Microwave ovens probably don't worry about mains frequency, but mains voltage might affect them.
OK thanks for confirming that.

Regards
Symon.
The newer ones, using inverters, probably arn't that bothered by fluctuations in mains voltage either.
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Old 30th Mar 2018, 2:26 pm   #127
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Default Re: Electric clocks running slow warning

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Originally Posted by Hartley118 View Post
I had some 'slow clocks' correspondence on Twitter with power station @Draxnews. They professed to know nothing of the UK low frequency problem, though they had featured the continental problem in an earlier news release.

This is disturbing because the massive potential 4GW output of Drax must alone be capable of influencing the grid frequency, given a little more steam input to their turbines.

Martin
I've just tweeted @nationalgriduk . I'll post any response here.
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Old 30th Mar 2018, 5:39 pm   #128
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Default Re: Electric clocks running slow warning

i was called into work at 4 am this morning the standby generators had to take over the building load the generators stated low supply frequency
i presume not enough power stations on line to hold at 50 hz
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Old 30th Mar 2018, 5:46 pm   #129
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Default Re: Electric clocks running slow warning

I wonder what's going on? There isn't unusually high demand at the moment despite it being a bit chilly. There's quite a lot of wind power entering the system and the coal plants seem to be barely idling. I still suspect some sort of technical issue affecting frequency stability, that or NG have given up bothering about it.

http://www.gridwatch.templar.co.uk
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Old 30th Mar 2018, 6:41 pm   #130
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Default Re: Electric clocks running slow warning

My Nixie mains derived clock is slow by about a minute too. It was set to summer time last weekend. I have a mains frequency meter (just for fun) and was going to make a mains cycle meter (MSF reference) I think I may resurrect the project.
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Old 30th Mar 2018, 6:47 pm   #131
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Default Re: Electric clocks running slow warning

Hi everyone. Have just joined the forum today as I noticed my Smiths synchronous wall clock has lost nearly a minute in the last week and was wondering how to 'fix' it. It seems from what you have discussed that it is something out of my control and there is nothing wrong with the clock (which is a relief)
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Old 30th Mar 2018, 6:49 pm   #132
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Default Re: Electric clocks running slow warning

I wok in the electricity supply industry, and while I can't offer a technical opinion, it might be useful to consider the 50Hz grid frequency number from the perspective of why it exists at all.

The frequency of supply is, necessarily, dynamic. It needs to change in response not only to the different magnitude and nature of load, but also to the way in which that load is supplied. For that reason, it was never intended as a frequency standard - that is an incidental use which has been made of the electricity supply. There are alternative and far more accurate frequency standards designed for that purpose.

The grid code uses frequency to control the grid.There is a 'Target Frequency' but that's only one definition in the code. More important are the specs for changes of frequency, both in rate and magnitude, which trigger different actions for both those who put power on and take power off the grid. Those actions ensure that power is available to all in adequate quantities exactly when required.

The grid code is an unwieldy document, and it sets very stiff obligations on commercial operators who supply power to the grid - this has arguably become more important in recent years when power is supplied by a larger number of smaller generating units.

In short, I would argue that grid frequency is not there to be a standard in itself, but as a tool to enable the grid to do its job.

Using the grid frequency as a standard for timekeeping means accepting the grid code (ie nominally 50Hz, controlled between 49.5Hz -50.5Hz) and the error implicit in that.

The grid code sets acceptable frequency ranges but there are no obligations to put extra cycles in (or take extra cycles out) so that an exact number of cycles are delivered over a set period of a day, a week or a year. To do so would be utterly contrary to efficient, stable electricity supply.

Synchronous clocks might mean we can record that average grid frequency has tended below a nominal 50Hz over a period, but that doesn't mean that there has been a failure to keep to the standards set by the code. There is a reporting mechanism on grid transactions at:

https://www.bmreports.com

This is where system notifications are posted in the event of forecast shortfalls in power etc.

For interest, a couple of extracts from the code:


Grid Code Definitions-
Target frequency :That Frequency determined by NGET, in its reasonable opinion, as the desired operating Frequency of the Total System. This will normally be
50.00Hz plus or minus 0.05Hz, except in exceptional circumstances as determined by NGET, in its reasonable opinion when this may be 49.90 or 50.10Hz. An example of exceptional circumstances may be difficulties
caused in operating the System during disputes affecting fuel supplies.



Grid Frequency Variations

CC.6.1.2 The Frequency of the National Electricity Transmission System shall be nominally 50Hz
and shall be controlled within the limits of 49.5 - 50.5Hz unless exceptional circumstances prevail.
CC.6.1.3 The System Frequency could rise to 52Hz or fall to 47Hz in exceptional circumstances.
Design of User's Plant and Apparatus and OTSDUW Plant and Apparatus must enable operation of that Plant and Apparatus within that range in accordance with the following:
Frequency Range Requirement
51.5Hz - 52Hz Operation for a period of at least 15 minutes is required each time the Frequency is above 51.5Hz.
51Hz - 51.5Hz Operation for a period of at least 90 minutes is required each time the Frequency is above 51Hz.
49.0Hz - 51Hz Continuous operation is required
47.5Hz - 49.0Hz Operation for a period of at least 90 minutes is required each time the Frequency is below 49.0Hz.
47Hz - 47.5Hz Operation for a period of at least 20 seconds is required each time the Frequency is below 47.5Hz.
For the avoidance of doubt, disconnection, by frequency or speed based relays is not permitted within the frequency range 47.5Hz to 51.5Hz, unless agreed with NGET in accordance with CC.6.3.12.
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Old 30th Mar 2018, 7:10 pm   #133
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Default Re: Electric clocks running slow warning

Thanks for the insight Croozer.

It appears from the paper I referred to in post 71 above that (like many countries' grids) National Grid did maintain a fixed number of cycles over longer time periods in 2016 whether that was a requirement or not. From the evidence presented by the synchronous clock users here they don't now.
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Old 30th Mar 2018, 7:46 pm   #134
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Default Re: Electric clocks running slow warning

I have tried to get information from my electricity provider without sucess. The national Grid phone number I was given just deals with gas!.
The energy ombudsman sent me back to my provider, no-one seems to know what is happening, I was even told that the transformer down by the school was changing the frequency. I had to explain to a couple of people what synchronous meant.

I was thinking of a letter to my MP may do some good but he has not done anything about the Ambergate hydroelectric scheme or the electrification of the rail line through Derby. Democracy does not apply here.
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Old 30th Mar 2018, 8:21 pm   #135
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Default Re: Electric clocks running slow warning

As with many privatised and subcontracted industries, there is no avenue for the general public to communicate with National Grid or the power generators, just as they can't communicate with Arqiva regarding broadcast transmitter issues, or BT Openreach regarding broadband faults. NG don't have a commercial relationship with end customers so don't see any need to interact with them. All interaction is supposed to be through your retail electricity company, though they are likely to know little or nothing about generation issues.

Of course, NG may respond to friendly informal contact.
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Old 30th Mar 2018, 9:06 pm   #136
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Default Re: Electric clocks running slow warning

On the continent, the higher target frequency is working and clocks are now catching up. The 6 minute loss is now 4 minutes so in a few weeks the clocks that were behind should give the correct time once again. The UK still being behind, confirms that the grids aren't actually coupled.
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Old 30th Mar 2018, 10:01 pm   #137
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Default Re: Electric clocks running slow warning

Hi.

There's some further interesting reading on this Dutch website http://wwwhome.cs.utwente.nl/~ptdeboer/misc/mains.html

Regards
Symon.
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Old 30th Mar 2018, 11:00 pm   #138
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Default Re: Electric clocks running slow warning

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On the continent, the higher target frequency is working and clocks are now catching up. The 6 minute loss is now 4 minutes so in a few weeks the clocks that were behind should give the correct time once again
That rather worries me! Are you saying that a clock installed today, will in a few weeks be 4 minutes fast?
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Old 31st Mar 2018, 1:31 am   #139
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Default Re: Electric clocks running slow warning

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Originally Posted by stuarth View Post
And don't rely on the pips on a DAB radio!
Piers Morgan on ITV Breakfast, often gives the current time to the audience in hours minutes & seconds. Someone should tell him why that's not helpful.
Any volunteers?
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Old 31st Mar 2018, 2:45 am   #140
Maarten
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Default Re: Electric clocks running slow warning

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Originally Posted by kalee20 View Post
That rather worries me! Are you saying that a clock installed today, will in a few weeks be 4 minutes fast?
It will, but after that it should stay at 4 minutes fast. I guess they deemed long term stability for clocks that aren't easily accessible to correct, more important.
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