Groups > sci.electronics.design > #446760

Re: OT: Current standard for watch precision

From	Jeroen Belleman <jeroen@nospam.please>
Newsgroups	sci.electronics.design
Subject	Re: OT: Current standard for watch precision
Date	2017-02-08 11:01 +0100
Organization	Aioe.org NNTP Server
Message-ID	<o7eq9n$157g$1@gioia.aioe.org> (permalink)
References	(4 earlier) <o7btns$k90$1@dont-email.me> <m6rj9ctrb76kmetgvmk966eiqqqovlsvlp@4ax.com> <o7dhq2$opl$1@dont-email.me> <d4120ef3-f2b0-4bd6-be60-66e76fa4737b@googlegroups.com> <27ll9c1rn1mg14c2t9rgtpvee6sedka25n@4ax.com>

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On 2017-02-08 09:25, upsidedown@downunder.com wrote:
> On Tue, 7 Feb 2017 14:52:09 -0800 (PST), Lasse Langwadt Christensen
> <langwadt@fonz.dk> wrote:
>
>> Den tirsdag den 7. februar 2017 kl. 23.32.16 UTC+1 skrev rickman:
>>> On 2/7/2017 10:56 AM, upsidedown@downunder.com wrote:
>>>> On Tue, 7 Feb 2017 02:43:33 -0500, rickman <gnuarm@gmail.com> wrote:
>>>>
>>>>>
>>>>> I also remember building a clock with a vacuum florescent display with a
>>>>> trimmer.  I was adjusting it by beating a 60 Hz output against the power
>>>>> line.  I could get it very, very close, but then ten or fifteen minutes
>>>>> later it would drift again!  It took me awhile before I realized that
>>>>> wasn't the clock, it was the power line.  lol
>>>>>
>>>>> Does the power line still drift like that?  Is there a reason why it
>>>>> would in this day with the many sources of accurate timing available?
>>>>> I'd expect the many generators could do a much better job of not running
>>>>> up and down in frequency so much, or is this an inherent aspect of a
>>>>> widely distributed network?
>>>>
>>>> This is exactly how synchronous AC generators are operated. A changing
>>>> load will slightly change the frequency and the primary mover (water,
>>>> steam) are adjusted accordingly. The variation is small and the error
>>>> in a mains synchronized clocks is usually below 10 to 15 s. During the
>>>> night, the network is running slightly above nominal frequency, in
>>>> order to catch up before the next morning.
>>>
>>> I think there is more to it than that.  We aren't talking about a single
>>> generator, we are dealing with a country wide network that has to stay
>>> very close to in phase.  I would be *very* surprised to find the grid
>>> would drift by multiple seconds within a day.
>>
>> on the page Jeff linked to it says they can catch up ~17 seconds a day,
>> once they get 20 seconds out of sync
>>
>> and it is just country wide, the synchronous grid of Continental Europe
>> 667 gigawatts in 20 some countries
>
> There are thousands of generators connected in parallel and the
> fluctuating frequency ensures that there are proper load sharing
> between generators. This method has been used for more than a century.
>
>

In an interconnected network of many synchronous generators, there
is no way that any single generator can affect the grid frequency.
All generators are necessarily running at the same frequency, and
for efficiency reasons, they also all try to stay in phase.

Still, the frequency of the whole network tends to drift up and
down with demand. In most power plants, the mains frequency error
is used as an input to regulators that control the power produced
by steam or water turbines driving the generators, which collectively
strive to keep the frequency constant. Small plants need not
bother to do so and merely keep their power output constant
and their phase synchronous.

In addition, in the distribution network, there are regulators
that control demand by affecting the mains voltage, by switching
in or out customers that have agreed to being remotely controlled,
or in extreme cases, by shedding the load of some subnets altogether.

With all these coupled rotating machines, the system as a whole
has a lot of inertia and the system time constant is of the order
of ten seconds, give or take a factor of three. The static gain
of the European network is of the order of 20GW/Hz. Typically the
frequency deviation is less than 50mHz. A central authority
somewhere in Switzerland (for the European network) keeps track
of the overall integrated frequency error and distributes data
used to change the regulator set points to keep the long-term
average frequency on target.

Jeroen Belleman

Thread

OT: Current standard for watch precision Pimpom <pimpom@invalid.com> - 2017-02-06 11:22 +0530
  Re: OT: Current standard for watch precision Phil Allison <pallison49@gmail.com> - 2017-02-05 22:13 -0800
    Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 17:15 +0530
      Re: OT: Current standard for watch precision Phil Allison <pallison49@gmail.com> - 2017-02-06 05:11 -0800
        Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 19:30 +0530
          Re: OT: Current standard for watch precision Phil Allison <pallison49@gmail.com> - 2017-02-06 06:33 -0800
            Re: OT: Current standard for watch precision nub12 <nub12@null.com> - 2017-02-07 07:57 +0800
        Re: OT: Current standard for watch precision Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:06 -0800
      Re: OT: Current standard for watch precision Tauno Voipio <tauno.voipio@notused.fi.invalid> - 2017-02-06 20:16 +0200
        Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-07 00:12 +0530
        Re: OT: Current standard for watch precision Don Y <blockedofcourse@foo.invalid> - 2017-02-06 11:58 -0700
      Re: OT: Current standard for watch precision Jasen Betts <jasen@xnet.co.nz> - 2017-02-07 05:50 +0000
        Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-07 02:43 -0500
          Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-07 14:53 +0530
            Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-07 12:32 -0500
          Re: OT: Current standard for watch precision Phil Allison <pallison49@gmail.com> - 2017-02-07 02:33 -0800
          Re: OT: Current standard for watch precision upsidedown@downunder.com - 2017-02-07 17:56 +0200
            Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-07 17:32 -0500
              Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-07 14:52 -0800
                Re: OT: Current standard for watch precision upsidedown@downunder.com - 2017-02-08 10:25 +0200
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-08 03:37 -0500
                Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-08 09:01 +0000
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-08 05:24 -0500
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 09:08 -0800
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-08 16:04 -0500
                Re: OT: Current standard for watch precision Clifford Heath <no.spam@please.net> - 2017-02-09 08:12 +1100
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-08 17:28 -0500
                Re: OT: Current standard for watch precision pcdhobbs@gmail.com - 2017-02-08 16:19 -0800
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 00:36 -0500
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 00:38 -0500
                Re: OT: Current standard for watch precision Clifford Heath <no.spam@please.net> - 2017-02-09 18:39 +1100
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 04:16 -0500
                Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-09 09:46 +0000
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 05:03 -0500
                Re: OT: Current standard for watch precision Jeroen Belleman <jeroen@nospam.please> - 2017-02-09 11:45 +0100
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 07:12 -0500
                Re: OT: Current standard for watch precision Jeroen Belleman <jeroen@nospam.please> - 2017-02-09 13:31 +0100
                Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-09 12:14 +0000
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 07:25 -0500
                Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-10 09:17 +0000
                Re: OT: Current standard for watch precision Jeroen Belleman <jeroen@nospam.please> - 2017-02-10 10:45 +0100
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-10 21:56 -0500
                Re: OT: Current standard for watch precision Jasen Betts <jasen@xnet.co.nz> - 2017-02-11 02:06 +0000
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-10 22:24 -0500
                Re: OT: Current standard for watch precision Jasen Betts <jasen@xnet.co.nz> - 2017-02-11 01:54 +0000
                Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-10 18:10 -0800
                Re: OT: Current standard for watch precision Cursitor Doom <curd@notformail.com> - 2017-02-08 23:34 +0000
                Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-08 15:49 -0800
                Re: OT: Current standard for watch precision pcdhobbs@gmail.com - 2017-02-08 15:55 -0800
                Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-08 16:08 -0800
                Re: OT: Current standard for watch precision Ralph Barone <ralph@invalid.com> - 2017-02-09 03:24 +0000
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 20:34 -0800
                Re: OT: Current standard for watch precision Tim Wescott <tim@seemywebsite.com> - 2017-02-08 23:26 -0600
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 23:28 -0800
                Re: OT: Current standard for watch precision Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-02-09 00:48 -0500
                Re: OT: Current standard for watch precision George Herold <gherold@teachspin.com> - 2017-02-09 06:52 -0800
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-09 20:37 -0500
                Re: OT: Current standard for watch precision Cursitor Doom <curd@notformail.com> - 2017-02-10 17:11 +0000
                Re: OT: Current standard for watch precision upsidedown@downunder.com - 2017-02-09 23:13 +0200
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-08 20:17 -0500
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 19:29 -0800
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 20:16 -0800
                Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-08 17:13 +0000
                Re: OT: Current standard for watch precision kevin93 <kevin@whitedigs.com> - 2017-02-08 12:54 -0800
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-08 12:35 -0500
                Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-08 09:50 -0800
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-08 13:14 -0500
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-08 11:35 -0800
                Re: OT: Current standard for watch precision upsidedown@downunder.com - 2017-02-08 23:16 +0200
                Re: OT: Current standard for watch precision Jeroen Belleman <jeroen@nospam.please> - 2017-02-09 09:59 +0100
                Re: OT: Current standard for watch precision Lasse Langwadt Christensen <langwadt@fonz.dk> - 2017-02-08 09:41 -0800
                Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-08 13:15 -0500
                Re: OT: Current standard for watch precision Jasen Betts <jasen@xnet.co.nz> - 2017-02-11 01:46 +0000
                Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-10 22:12 -0500
                Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-09 15:25 -0800
                Re: OT: Current standard for watch precision Clifford Heath <no.spam@please.net> - 2017-02-10 10:38 +1100
                Re: OT: Current standard for watch precision bill.sloman@ieee.org - 2017-02-09 17:42 -0800
                Re: OT: Current standard for watch precision Jeroen Belleman <jeroen@nospam.please> - 2017-02-08 11:01 +0100
                Re: OT: Current standard for watch precision Jasen Betts <jasen@xnet.co.nz> - 2017-02-11 04:06 +0000
              Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-07 21:02 -0500
          Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-07 10:24 -0800
            Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-07 10:48 -0800
              Re: OT: Current standard for watch precision George Herold <gherold@teachspin.com> - 2017-02-07 11:12 -0800
                Re: OT: Current standard for watch precision Mikko OH2HVJ <mikko.syrjalahti@nospam.fi> - 2017-02-08 09:33 +0200
                Re: OT: Current standard for watch precision George Herold <gherold@teachspin.com> - 2017-02-08 06:31 -0800
      Re: OT: Current standard for watch precision Martin Brown <|||newspam|||@nezumi.demon.co.uk> - 2017-02-07 09:58 +0000
    Re: OT: Current standard for watch precision Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:00 -0800
  Re: OT: Current standard for watch precision Jeff Liebermann <jeffl@cruzio.com> - 2017-02-05 23:01 -0800
  Re: OT: Current standard for watch precision mike <ham789@netzero.net> - 2017-02-06 03:21 -0800
    Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 17:25 +0530
  Re: Current standard for watch precision "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-06 06:57 -0600
    Re: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 19:10 +0530
      Re: Current standard for watch precision "Tim Williams" <tiwill@seventransistorlabs.com> - 2017-02-06 08:13 -0600
        Re: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 21:04 +0530
      Re: Current standard for watch precision Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-02-06 09:30 -0500
        Re: Current standard for watch precision George Herold <gherold@teachspin.com> - 2017-02-06 06:56 -0800
      Re: Current standard for watch precision Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:11 -0800
    Re: Current standard for watch precision Don Y <blockedofcourse@foo.invalid> - 2017-02-06 12:04 -0700
      Re: Current standard for watch precision Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 14:58 -0700
        Re: Current standard for watch precision Don Y <blockedofcourse@foo.invalid> - 2017-02-06 15:21 -0700
          Re: Current standard for watch precision Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 16:06 -0700
            Re: Current standard for watch precision Don Y <blockedofcourse@foo.invalid> - 2017-02-06 17:19 -0700
              Re: Current standard for watch precision Jim Thompson <To-Email-Use-The-Envelope-Icon@On-My-Web-Site.com> - 2017-02-06 17:52 -0700
                Re: Current standard for watch precision Don Y <blockedofcourse@foo.invalid> - 2017-02-06 17:55 -0700
      Re: Current standard for watch precision krw@notreal.com - 2017-02-06 21:44 -0500
    Re: Current standard for watch precision Robert Baer <robertbaer@localnet.com> - 2017-02-08 20:04 -0800
  Re: OT: Current standard for watch precision Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> - 2017-02-06 09:06 -0500
    Re: OT: Current standard for watch precision Pimpom <Pimpom@invalid.com> - 2017-02-06 21:04 +0530
  Re: OT: Current standard for watch precision TTman <pcw1.cad@ntlworld.com> - 2017-02-06 14:31 +0000
    Re: OT: Current standard for watch precision Clifford Heath <no.spam@please.net> - 2017-02-07 08:54 +1100
  Re: OT: Current standard for watch precision Tim Wescott <seemywebsite@myfooter.really> - 2017-02-06 17:33 -0600
  Re: OT: Current standard for watch precision krw@notreal.com - 2017-02-06 21:23 -0500
  Re: OT: Current standard for watch precision prairiesky <outgoing.server@mozilla.com> - 2017-02-06 23:00 -0800
  Re: OT: Current standard for watch precision Cursitor Doom <curd@notformail.com> - 2017-02-07 18:29 +0000
  Re: OT: Current standard for watch precision Robert Baer <robertbaer@localnet.com> - 2017-02-08 19:59 -0800
    Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 00:48 -0500
      Re: OT: Current standard for watch precision Tim Wescott <tim@seemywebsite.com> - 2017-02-08 23:54 -0600
        Re: OT: Current standard for watch precision Tim Wescott <tim@seemywebsite.com> - 2017-02-09 00:00 -0600
        Re: OT: Current standard for watch precision rickman <gnuarm@gmail.com> - 2017-02-09 04:57 -0500

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