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Groups > sci.electronics.design > #446378 > unrolled thread
| Started by | Pimpom <pimpom@invalid.com> |
|---|---|
| First post | 2017-02-06 11:22 +0530 |
| Last post | 2017-02-09 04:57 -0500 |
| Articles | 20 on this page of 119 — 31 participants |
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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
Page 3 of 6 — ← Prev page 1 2 [3] 4 5 6 Next page →
| From | Jeroen Belleman <jeroen@nospam.please> |
|---|---|
| Date | 2017-02-10 10:45 +0100 |
| Message-ID | <o7k236$ffu$1@gioia.aioe.org> |
| In reply to | #447143 |
On 2017-02-10 10:17, Martin Brown wrote: > On 09/02/2017 12:25, rickman wrote: [Snip!] >> The phase is what controls the time on the clocks. That is the >> thing that gets adjusted over the course of the day/week/month to >> keep the clocks running on time. > > No it isn't. YOU have failed to understand the basics. It is the > average frequency that is kept tightly constrained over a 24 hour > period and kept even more accurate over the longer term. Hmm. Frequency is merely the rate of change of phase. You control one, you affect the other accordingly. There is no freedom here. Jeroen Belleman
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| From | rickman <gnuarm@gmail.com> |
|---|---|
| Date | 2017-02-10 21:56 -0500 |
| Message-ID | <o7luds$d5q$1@dont-email.me> |
| In reply to | #447143 |
On 2/10/2017 4:17 AM, Martin Brown wrote: > On 09/02/2017 12:25, rickman wrote: >> On 2/9/2017 7:14 AM, Martin Brown wrote: >>> On 09/02/2017 10:03, rickman wrote: >>>> On 2/9/2017 4:46 AM, Martin Brown wrote: >>>>> On 09/02/2017 05:36, rickman wrote: >>>>>> On 2/8/2017 7:19 PM, pcdhobbs@gmail.com wrote: >>>>>>>> That doesn't explain how the "herd" is controlled. >>>>>>> >>>>>>> It's mostly large-scale rotating machinery with a lot of inertia. >>>>>>> When >>>>>>> the load exceeds the input, the 'herd' slows down. Thus you keep the >>>>>>> system in balance by watching the frequency. >>>>>> >>>>>> That's not the question I'm asking. >>>>> >>>>> But it is the answer to how does it all work together. An offline >>>>> generator carefully syncs itself to the herd before joining the pack >>>>> and >>>>> once connected to the grid is locked to it by the sheer momentum of >>>>> the >>>>> mechanical energy in the turbines and the drag created by the load. >>>>> >>>>> Entrainment describes the tendency of oscillators at similar >>>>> frequencies >>>>> to lock step even when you don't want them to. >>>> >>>> I'm not asking how they lock to each other. That I get. I'm asking >>>> how >>>> the herd is steered. I'm told in Europe they have a single measurement >>>> of the frequency or more likely the phase and once a day an order is >>>> sent out for all of the operators to change their speeds. >>> >>> OK. In familiar control terms there is a local proportional to error >>> control loop on each generator that tries to maintain frequency and in >>> addition there is an integral control loop over 24 hours that tries to >>> maintain the running average equal to nominal cycles/day too. >>> >>> The latter is the one done supra nationally by asking a few of the most >>> powerful stations to up their output slightly at night. >>>> >>>> But if they are all synced to each other, how do they change the speed? >>>> Each one is outputting some amount of energy which has to do with >>>> demand >>>> (which I also don't see how they know how much energy to create). >>>> Theoretically they are only producing the energy their customers are >>>> asking for and get billed for. >>> >>> If the torque applied by the mechanical drive system exceeds the drag >>> presented by the load the whole system spins up very slightly. The ones >>> now outputting extra power making life easier for the others. >>> >>>>>> You have 10,000 people on a ship as oarsmen. None can really see the >>>>>> others, but they all can hear each other and they all chant the >>>>>> cadence >>>>>> as they paddle. It is *much* more effective if they all stroke >>>>>> together. There is no guy on deck with a drum, just the chorus of >>>>>> voices crying, "stroke, stroke,..." >>>>>> >>>>>> The pilot can talk to any of the oarsmen singly. Or maybe he has an >>>>>> intercom that lets him talk to them all. I don't know. >>>>>> >>>>>> If the pilot wants to speed up the boat, what does he do? >>>>> >>>>> Asks a few of the biggest or most responsive units to increase their >>>>> output accordingly or to come onstream if they are really short of >>>>> power. UK uses pumped storage to handle short term transient loads >>>>> like >>>>> soap opera advert breaks and half time at televised football matches. >>>> >>>> No one said they are short of power. Say the power is perfectly >>>> matched, but the phase has drifted behind. The power they generate >>>> needs to match the power being consumed by their customers, no? >>> >>> The phase is irrelevant apart from when you are connecting a new power >>> station into the grid when it needs to be matched up first. Once >>> connected up its speed it regulated by the whole ensemble and daily >>> corrections are done by cycle counting and an integral control loop. >> >> This conversation gets old when people don't understand the basics. > > And that is *YOU*. The phase is drifting out by more 2pi every thousand > cycles when the frequency is just 0.1Hz off its nominal value (a common > situation). Just about all clocks work by dividing down some form of > oscillator signal and rely on counting the *cycles* of that signal. And a cycle is just 360 degrees of /phase/. So to keep the clocks right, phase is what has to be tracked unless you wish to track frequency and integrate which is not recommended for long term accuracy. > The phase error merely represents sub cycle jitter on that timing > resolution - which may be important in some time critical applications > like interferometry or ultra precision timekeeping for GPS. Time error is also a phase error in a sinusoid and is important to most measurements. >> The >> phase is what controls the time on the clocks. That is the thing that >> gets adjusted over the course of the day/week/month to keep the clocks >> running on time. > > No it isn't. YOU have failed to understand the basics. It is the average > frequency that is kept tightly constrained over a 24 hour period and > kept even more accurate over the longer term. If you don't think the phase of a sine is important, then you don't know what a sine is. Time error is the integral of frequency error. In other words, the total drift in phase. >>> It is a dynamic system where the instantaneous load is never quite >>> matched to the demand which is why the frequency is allowed to vary. It >>> would be too costly to try and hold it to a tighter tolerance. >>> >>>>>> That's what I'm asking about keeping the grid on sync with the time. >>>>>> How >>>>>> does the pilot control the oarsmen and how do the oarsmen keep in >>>>>> step >>>>>> but also nudge the stroke? >>>>> >>>>> They can all monitor grid frequency and so know which way they are >>>>> aiming for in a classic local control loop. But the ensemble average >>>>> works much better than the regulation on any single unit. >>>> >>>> So everyone acts independently? >>> >>> The first order control is eliminate proportional error from the target >>> frequency but that is never achieved in practice. So the next level >>> correction is based on the integral number of cycles in 24 hours (which >>> can also be measured and determined locally but ISTR is for historical >>> reasons is done centrally by CEGB in the UK). They have a much better >>> understanding of the national and international predicted load profile >>> than any one generating plant can possibly have. >> >> The grid is nudged by power generators outputting more power than >> "something". I don't know what the "something" is. Meanwhile each >> generator is charging a customer somewhere and they can only bill them >> for what they are using. So how can a power plant output more power >> than they are billing and still make profit? > > The "something" is the load on the other end. Energy is conserved so the > extra torque they input results in spinning up the generators. > Equivalently they can ask some of the biggest sink loads to drop off and > exactly the same would happen. I begin to think you are either extremely > stupid or are deliberately trolling. Which load? Each power station is theoretically supplying customers distributed over the grid. The power output by the station should match the load their customers represent (ignoring losses for the moment). The power grid is not a Marxist society "from each according to ability", etc. You are simply describing a minor part of the physics involved. I am sure the real control system is much more complex. Otherwise there would be no way to account for the power generated. There is a lot of complexity to this that no one here seems to appreciate. . If you think I am trolling you should just stop conversing.. NOW! -- Rick C
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| From | Jasen Betts <jasen@xnet.co.nz> |
|---|---|
| Date | 2017-02-11 02:06 +0000 |
| Message-ID | <o7lrib$fb6$3@gonzo.alcatraz> |
| In reply to | #446993 |
On 2017-02-09, rickman <gnuarm@gmail.com> wrote: > On 2/9/2017 4:46 AM, Martin Brown wrote: >>> That's what I'm asking about keeping the grid on sync with the time. How >>> does the pilot control the oarsmen and how do the oarsmen keep in step >>> but also nudge the stroke? >> >> They can all monitor grid frequency and so know which way they are >> aiming for in a classic local control loop. But the ensemble average >> works much better than the regulation on any single unit. > > So everyone acts independently? everyone co-operates towards the same goal, eg: gain 10 cycles in the next 24h) -- This email has not been checked by half-arsed antivirus software
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| From | krw@notreal.com |
|---|---|
| Date | 2017-02-10 22:24 -0500 |
| Message-ID | <io0t9c96b5d0frcj0162ut1a7ljvpcfjjp@4ax.com> |
| In reply to | #447264 |
On 11 Feb 2017 02:06:03 GMT, Jasen Betts <jasen@xnet.co.nz> wrote: >On 2017-02-09, rickman <gnuarm@gmail.com> wrote: >> On 2/9/2017 4:46 AM, Martin Brown wrote: > >>>> That's what I'm asking about keeping the grid on sync with the time. How >>>> does the pilot control the oarsmen and how do the oarsmen keep in step >>>> but also nudge the stroke? >>> >>> They can all monitor grid frequency and so know which way they are >>> aiming for in a classic local control loop. But the ensemble average >>> works much better than the regulation on any single unit. >> >> So everyone acts independently? > >everyone co-operates towards the same goal, eg: gain 10 cycles in >the next 24h) As has been pointed out, here, not "everyone's" cooperation is necessary. Only a few of the big players are necessary to push the frequency, one way or the other. Everyone else is naturly locked to them (just keep their power ouput constant).
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| From | Jasen Betts <jasen@xnet.co.nz> |
|---|---|
| Date | 2017-02-11 01:54 +0000 |
| Message-ID | <o7lqsv$fb6$2@gonzo.alcatraz> |
| In reply to | #446973 |
On 2017-02-09, rickman <gnuarm@gmail.com> wrote: > On 2/8/2017 7:19 PM, pcdhobbs@gmail.com wrote: > If the pilot wants to speed up the boat, what does he do? > > That's what I'm asking about keeping the grid on sync with the time. > How does the pilot control the oarsmen and how do the oarsmen keep in > step but also nudge the stroke? the oars are actually interconnected with bungee cords, so even undriven one oar will still keep time with the others. -- This email has not been checked by half-arsed antivirus software
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| From | Lasse Langwadt Christensen <langwadt@fonz.dk> |
|---|---|
| Date | 2017-02-10 18:10 -0800 |
| Message-ID | <5f06dd58-ea97-4f66-9aff-672c3fd48796@googlegroups.com> |
| In reply to | #447257 |
Den lørdag den 11. februar 2017 kl. 03.01.02 UTC+1 skrev Jasen Betts: > On 2017-02-09, rickman <gnuarm@gmail.com> wrote: > > On 2/8/2017 7:19 PM, pcdhobbs@gmail.com wrote: > > > If the pilot wants to speed up the boat, what does he do? > > > > That's what I'm asking about keeping the grid on sync with the time. > > How does the pilot control the oarsmen and how do the oarsmen keep in > > step but also nudge the stroke? > > the oars are actually interconnected with bungee cords, so even undriven > one oar will still keep time with the others. https://patchnride.files.wordpress.com/2014/06/multiple-tandem.gif
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| From | Cursitor Doom <curd@notformail.com> |
|---|---|
| Date | 2017-02-08 23:34 +0000 |
| Message-ID | <o7g9ui$k8$8@dont-email.me> |
| In reply to | #446863 |
On Thu, 09 Feb 2017 08:12:39 +1100, Clifford Heath wrote: > The generators will tend to phase lock by themselves because of the > load. If you feed in more power (more steam, water, etc) then its phase > will just move ahead slightly. Loss of lock would be disastrous. Back in the 1970s/early 80s,the BBC's World Service *had* to broadcast the Today show on its Radio 4 channel without fail every day, because the absence of that signal for just 2 days was understood by RN submarine commanders to trigger a flat-out nuclear strike against Russia. If the national grid went down, they had two standby 1MW diesel generators side- by-side (just in case one failed) which could be fired up to get back on air again. I remember meeting the guy who's job it was to synch the gennies back and forth to the National Grid during power outages. He said it was the worst job in the world because of the danger involved (at all sorts of levels) if he got it just the tiniest bit wrong.
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| From | Lasse Langwadt Christensen <langwadt@fonz.dk> |
|---|---|
| Date | 2017-02-08 15:49 -0800 |
| Message-ID | <e3e4de31-7d42-4f6e-8075-26ea9a1b1d85@googlegroups.com> |
| In reply to | #446906 |
Den torsdag den 9. februar 2017 kl. 00.36.32 UTC+1 skrev Cursitor Doom: > On Thu, 09 Feb 2017 08:12:39 +1100, Clifford Heath wrote: > > > The generators will tend to phase lock by themselves because of the > > load. If you feed in more power (more steam, water, etc) then its phase > > will just move ahead slightly. Loss of lock would be disastrous. > > Back in the 1970s/early 80s,the BBC's World Service *had* to broadcast > the Today show on its Radio 4 channel without fail every day, because the > absence of that signal for just 2 days was understood by RN submarine > commanders to trigger a flat-out nuclear strike against Russia. If the > national grid went down, they had two standby 1MW diesel generators side- > by-side (just in case one failed) which could be fired up to get back on > air again. I remember meeting the guy who's job it was to synch the > gennies back and forth to the National Grid during power outages. He said > it was the worst job in the world because of the danger involved (at all > sorts of levels) if he got it just the tiniest bit wrong. done all the time on ships, can't be that dangerous http://www.marineinsight.com/tech/generator/how-to-synchronize-generators-on-a-ship/
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| From | pcdhobbs@gmail.com |
|---|---|
| Date | 2017-02-08 15:55 -0800 |
| Message-ID | <ea9b1e8f-0d1e-4bd9-8046-128b9d7d4c13@googlegroups.com> |
| In reply to | #446913 |
>done all the time on ships, can't be that dangerous >http://www.marineinsight.com/tech/generator/how-to-synchronize-generators-on-a-ship/ If you think "done all the time on ships" equates to "can't be all that dangerous", you've led a sheltered life. Cheers Phil Hobbs (Who has also led one, for the most part)
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| From | Lasse Langwadt Christensen <langwadt@fonz.dk> |
|---|---|
| Date | 2017-02-08 16:08 -0800 |
| Message-ID | <23bb052e-5166-4ba6-85a9-db80f49b8401@googlegroups.com> |
| In reply to | #446916 |
Den torsdag den 9. februar 2017 kl. 00.56.05 UTC+1 skrev pcdh...@gmail.com: > >done all the time on ships, can't be that dangerous > > >http://www.marineinsight.com/tech/generator/how-to-synchronize-generators-on-a-ship/ > > If you think "done all the time on ships" equates to "can't be all that dangerous", you've led a sheltered life. > yeh ships are probably not most known for their safe work environment ;) so "can't be all that dangerous" maybe the wrong way to put it, but since it is something that is regularly done I assume it very rarely ends with a big bang
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| From | Ralph Barone <ralph@invalid.com> |
|---|---|
| Date | 2017-02-09 03:24 +0000 |
| Message-ID | <o7gncr$1bc0$1@gioia.aioe.org> |
| In reply to | #446920 |
Lasse Langwadt Christensen <langwadt@fonz.dk> wrote: > Den torsdag den 9. februar 2017 kl. 00.56.05 UTC+1 skrev pcdh...@gmail.com: >>> done all the time on ships, can't be that dangerous >> >>> http://www.marineinsight.com/tech/generator/how-to-synchronize-generators-on-a-ship/ >> >> If you think "done all the time on ships" equates to "can't be all that >> dangerous", you've led a sheltered life. >> > > yeh ships are probably not most known for their safe work environment ;) > so "can't be all that dangerous" maybe the wrong way to put it, but since > it is something that is regularly done I assume it very rarely ends with > a big bang I recall hearing a story about a tech who was working in a small hydro generating plant who had found that a voltage transformer used to feed the local synchronizing relay had been connected 180° out of phase since the plant was built. He fixed the connection, then stuck around to watch the next synchronization. The generator breaker closed, then the local electrician said "Hey, what's wrong? Where's the huge bang?"
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| From | Jeff Liebermann <jeffl@cruzio.com> |
|---|---|
| Date | 2017-02-08 20:34 -0800 |
| Message-ID | <m9rn9ct198qvj56vppsnj10bv74524er2u@4ax.com> |
| In reply to | #446953 |
On Thu, 9 Feb 2017 03:24:11 +0000 (UTC), Ralph Barone <ralph@invalid.com> wrote: >I recall hearing a story about a tech who was working in a small hydro >generating plant who had found that a voltage transformer used to feed the >local synchronizing relay had been connected 180° out of phase since the >plant was built. He fixed the connection, then stuck around to watch the >next synchronization. The generator breaker closed, then the local >electrician said "Hey, what's wrong? Where's the huge bang?" One of my friends and customers has a nice Honda stationary generator at his house. Instead of a transfer switch, he uses the breaker panel. Since most of the house wiring was installed without the benefits of a licensed electrician or county inspector, as an alternative to a proper transfer switch, I was volunteered to write a fool proof procedure for startup and shutdown so that the owners clueless wife could start the generator when he wasn't home. We did two successful dry runs, but I could see she wasn't interested or paying attention. Last year, we had an opportunity to test my written procedure, in a pouring rain, of course. Everything went well until the utility power returned, stabilized, and it was time to switch back to utility power. She didn't bother following my procedure and put the generator in parallel with the AC power. It tripped 4 breakers (two on the generator and two in the electrical panel), made a rather loud noise, and knocked the unsecured generator on its side dumping some gasoline on the ground. The rain kept the gasoline from igniting and burning the house down. I guess Honda generators don't like instantaneous changes in phase. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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| From | Tim Wescott <tim@seemywebsite.com> |
|---|---|
| Date | 2017-02-08 23:26 -0600 |
| Message-ID | <8uCdnThekZ8fYAbFnZ2dnUU7-bWdnZ2d@giganews.com> |
| In reply to | #446966 |
On Wed, 08 Feb 2017 20:34:11 -0800, Jeff Liebermann wrote: > On Thu, 9 Feb 2017 03:24:11 +0000 (UTC), Ralph Barone > <ralph@invalid.com> wrote: > >>I recall hearing a story about a tech who was working in a small hydro >>generating plant who had found that a voltage transformer used to feed >>the local synchronizing relay had been connected 180° out of phase since >>the plant was built. He fixed the connection, then stuck around to watch >>the next synchronization. The generator breaker closed, then the local >>electrician said "Hey, what's wrong? Where's the huge bang?" > > One of my friends and customers has a nice Honda stationary generator at > his house. Instead of a transfer switch, he uses the breaker panel. > Since most of the house wiring was installed without the benefits of a > licensed electrician or county inspector, as an alternative to a proper > transfer switch, I was volunteered to write a fool proof procedure for > startup and shutdown so that the owners clueless wife could start the > generator when he wasn't home. We did two successful dry runs, but I > could see she wasn't interested or paying attention. > > Last year, we had an opportunity to test my written procedure, in a > pouring rain, of course. Everything went well until the utility power > returned, stabilized, and it was time to switch back to utility power. > She didn't bother following my procedure and put the generator in > parallel with the AC power. It tripped 4 breakers (two on the generator > and two in the electrical panel), made a rather loud noise, and knocked > the unsecured generator on its side dumping some gasoline on the ground. > The rain kept the gasoline from igniting and burning the house down. > > I guess Honda generators don't like instantaneous changes in phase. There's a gizmo you can buy for some breaker boxes that only lets breaker A go on if B is locked out, and visa-versa. I can't remember the details, but I do know that I saw a picture on the web and thought "that'd be easy to make!" It might just be a sliding bar. At any rate, it'd be easy to keep wifey from burning down the house, or electrocuting someone. -- Tim Wescott Control systems, embedded software and circuit design I'm looking for work! See my website if you're interested http://www.wescottdesign.com
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| From | Jeff Liebermann <jeffl@cruzio.com> |
|---|---|
| Date | 2017-02-08 23:28 -0800 |
| Message-ID | <645o9c10gkkncc6cajtrs4fnpj028vh2up@4ax.com> |
| In reply to | #446969 |
On Wed, 08 Feb 2017 23:26:26 -0600, Tim Wescott <tim@seemywebsite.com> wrote: >There's a gizmo you can buy for some breaker boxes that only lets breaker >A go on if B is locked out, and visa-versa. I can't remember the >details, but I do know that I saw a picture on the web and thought >"that'd be easy to make!" >It might just be a sliding bar. At any rate, it'd be easy to keep wifey >from burning down the house, or electrocuting someone. Generator interlock kit: <http://www.ebay.com/bhp/generator-interlock> That might have helped here except the owners wife probably could not manage to operate a screwdriver or socket wrench while standing on the ladder necessary to reach the switch, in pouring rain. Of course, every brand and style of circuit breaker box has its own unique interlock mechanism. Also, $60 for two pieces of sheet metal seems a bit much. It's not very fool proof as the average fool would unscrew all the mounting hardware and just remove the sheet metal in order to operate the desired breakers. There are plenty of kits for both manual and automatic transfer switches available: <https://www.google.com/search?q=transfer+switch&tbm=isch> Installing one was my first recommendation. However, there's a problem. If the work were done by a licensed electrician, he would likely take one look at the breaker box and house wiring, and demand that it all be ripped out and replaced. If the electrician doesn't demand that, the county electrical inspector will likely do the same. The owner didn't want to pay for all that, so he decided to continue with the existing system. Another problem is that transfer switches usually use a sub-panel for housing the transfer switch and the circuit breakers needed by the loads that are running on generator power. Unless one has a very large generator, it's not a great idea to power the entire house on generator power. I could have installed such a sub-panel and transfer switch, but one look at the existing wiring behind the main breaker panel told me that this was going to be a major challenge. I took photos and showed them to an electrician friend who's advice was to rip it all out and start over. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
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| From | Spehro Pefhany <speffSNIP@interlogDOTyou.knowwhat> |
|---|---|
| Date | 2017-02-09 00:48 -0500 |
| Message-ID | <se0o9ct1a2si586djiont33dc25hg5a5o4@4ax.com> |
| In reply to | #446966 |
On Wed, 08 Feb 2017 20:34:11 -0800, the renowned Jeff Liebermann <jeffl@cruzio.com> wrote: > > >Last year, we had an opportunity to test my written procedure, in a >pouring rain, of course. Everything went well until the utility power >returned, stabilized, and it was time to switch back to utility power. >She didn't bother following my procedure and put the generator in >parallel with the AC power. It tripped 4 breakers (two on the >generator and two in the electrical panel), made a rather loud noise, >and knocked the unsecured generator on its side dumping some gasoline >on the ground. The rain kept the gasoline from igniting and burning >the house down. > >I guess Honda generators don't like instantaneous changes in phase. Stuff like this makes me think of tort law and "Duty of Care" obligation...even on pro-bono stuff. I see manual 60A transfer switches for $85 US at Home Despot.. free shipping even. --sp -- Best regards, Spehro Pefhany
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| From | George Herold <gherold@teachspin.com> |
|---|---|
| Date | 2017-02-09 06:52 -0800 |
| Message-ID | <31a60123-0240-478b-ab81-350d84071827@googlegroups.com> |
| In reply to | #446966 |
On Wednesday, February 8, 2017 at 11:34:15 PM UTC-5, Jeff Liebermann wrote: > On Thu, 9 Feb 2017 03:24:11 +0000 (UTC), Ralph Barone > <ralph@invalid.com> wrote: > > >I recall hearing a story about a tech who was working in a small hydro > >generating plant who had found that a voltage transformer used to feed the > >local synchronizing relay had been connected 180° out of phase since the > >plant was built. He fixed the connection, then stuck around to watch the > >next synchronization. The generator breaker closed, then the local > >electrician said "Hey, what's wrong? Where's the huge bang?" > > One of my friends and customers has a nice Honda stationary generator > at his house. Instead of a transfer switch, he uses the breaker > panel. Since most of the house wiring was installed without the > benefits of a licensed electrician or county inspector, as an > alternative to a proper transfer switch, I was volunteered to write a > fool proof procedure for startup and shutdown so that the owners > clueless wife could start the generator when he wasn't home. We did > two successful dry runs, but I could see she wasn't interested or > paying attention. > > Last year, we had an opportunity to test my written procedure, in a > pouring rain, of course. Everything went well until the utility power > returned, stabilized, and it was time to switch back to utility power. > She didn't bother following my procedure and put the generator in > parallel with the AC power. It tripped 4 breakers (two on the > generator and two in the electrical panel), made a rather loud noise, > and knocked the unsecured generator on its side dumping some gasoline > on the ground. The rain kept the gasoline from igniting and burning > the house down. > > I guess Honda generators don't like instantaneous changes in phase. I do something similar, but there is no way I'm letting my wife touch it... George H. > > -- > Jeff Liebermann jeffl@cruzio.com > 150 Felker St #D http://www.LearnByDestroying.com > Santa Cruz CA 95060 http://802.11junk.com > Skype: JeffLiebermann AE6KS 831-336-2558
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| From | krw@notreal.com |
|---|---|
| Date | 2017-02-09 20:37 -0500 |
| Message-ID | <f96q9c58mfld1cq5im4gno72ss1h2r8vso@4ax.com> |
| In reply to | #446966 |
On Wed, 08 Feb 2017 20:34:11 -0800, Jeff Liebermann <jeffl@cruzio.com> wrote: >On Thu, 9 Feb 2017 03:24:11 +0000 (UTC), Ralph Barone ><ralph@invalid.com> wrote: > >>I recall hearing a story about a tech who was working in a small hydro >>generating plant who had found that a voltage transformer used to feed the >>local synchronizing relay had been connected 180° out of phase since the >>plant was built. He fixed the connection, then stuck around to watch the >>next synchronization. The generator breaker closed, then the local >>electrician said "Hey, what's wrong? Where's the huge bang?" > >One of my friends and customers has a nice Honda stationary generator >at his house. Instead of a transfer switch, he uses the breaker >panel. Since most of the house wiring was installed without the >benefits of a licensed electrician or county inspector, as an >alternative to a proper transfer switch, I was volunteered to write a >fool proof procedure for startup and shutdown so that the owners >clueless wife could start the generator when he wasn't home. We did >two successful dry runs, but I could see she wasn't interested or >paying attention. > >Last year, we had an opportunity to test my written procedure, in a >pouring rain, of course. Everything went well until the utility power >returned, stabilized, and it was time to switch back to utility power. >She didn't bother following my procedure and put the generator in >parallel with the AC power. It tripped 4 breakers (two on the >generator and two in the electrical panel), made a rather loud noise, >and knocked the unsecured generator on its side dumping some gasoline >on the ground. The rain kept the gasoline from igniting and burning >the house down. > >I guess Honda generators don't like instantaneous changes in phase. She's lucky she didn't kill a lineman. The power company frowns on it.
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| From | Cursitor Doom <curd@notformail.com> |
|---|---|
| Date | 2017-02-10 17:11 +0000 |
| Message-ID | <o7ks8c$fd9$6@dont-email.me> |
| In reply to | #446913 |
On Wed, 08 Feb 2017 15:49:48 -0800, Lasse Langwadt Christensen wrote: > done all the time on ships, can't be that dangerous > > http://www.marineinsight.com/tech/generator/how-to-synchronize- generators-on-a-ship/ Totally irrelevant comparison. I'm talking about synching between a million Watt generator and the *national grid* (at effectively unlimited energy potential.) Nothing you find on a ship compares to the NG.
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| From | upsidedown@downunder.com |
|---|---|
| Date | 2017-02-09 23:13 +0200 |
| Message-ID | <o1mp9ctvke1u370o51hgtar5j410ndb0nj@4ax.com> |
| In reply to | #446863 |
On Thu, 9 Feb 2017 08:12:39 +1100, Clifford Heath <no.spam@please.net> wrote: >On 09/02/17 08:04, rickman wrote: >> On 2/8/2017 12:08 PM, Jeff Liebermann wrote: >>> On Wed, 8 Feb 2017 05:24:35 -0500, rickman <gnuarm@gmail.com> wrote: >>>> Yes, but *how* do they run the grid faster or slower? Also, *who* >>>> controls this? >>> >>> This is cool. Crowd sourced utility frequency data: >>> "FNET/GridEye Web Display. U.S. Frequency Gradient Map" >>> <http://fnetpublic.utk.edu/gradientmap.html> (USA/Canada) >>> <http://powerit.utk.edu/worldmap/> (World) >>> Some detail on how it works: >>> <http://fnetpublic.utk.edu> >>> <https://en.wikipedia.org/wiki/FNET> >>> >>> Wikipedia article on Utility Freq: >>> <https://en.wikipedia.org/wiki/Utility_frequency#Stability> >>> Looks like it's run by the NERC: >>> <https://en.wikipedia.org/wiki/North_American_Electric_Reliability_Corporation> >>> >>> but I couldn't find anything involving frequency control on their web >>> pile. >>> >>> "How do power plants maintain a 60 Hz frequency?" >>> <https://www.reddit.com/r/askscience/comments/1kpx0l/how_do_power_plants_maintain_a_60_hz_frequency/> >>> >>> >>> My guess(tm) is the actual speed adjustment varies by the generator >>> type. For solar, there's a DC to AC inverter which can be controlled >>> electronically. For hydro, vary the flow rate to match the load. For >>> steam power, vary the steam pressure to match the load. Since both >>> the load and the flow/pressure affects the frequency, the steam >>> pressure, flow rate, etc will need to track to considerable precision. >>> >>> There's also a proposal to eliminate the TEC (time error correction): >>> "Time Error Correction and Reliability White Paper" >>> <http://www.nerc.com/pa/Stand/Project%2020101422%20Phase%202%20of%20BARC%20%20BAL004%20DL/BAL-004-0_White_Paper_Clean_09242015.pdf> >>> >> >> Thanks for all the links, but they don't actually explain the mechanism >> for how the various generators are adjusted to maintain the grid >> frequency > >The generators will tend to phase lock by themselves because of >the load. If you feed in more power (more steam, water, etc) >then its phase will just move ahead slightly. The big _synchronous_ AC generators (hydro/steam) are actually phase locked and hence respond to small phase changes. Any power plant generator contains protection relays for abnormal situation .e.g. if the unit drops behind generation and becomes a motor and hence must be discounted from the network. Wind turbines are usually _asynchronous_ generators and they are modeled as frequency control loops.
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| From | krw@notreal.com |
|---|---|
| Date | 2017-02-08 20:17 -0500 |
| Message-ID | <klgn9c5ooo2c4h8srkuc852532l679av2t@4ax.com> |
| In reply to | #446857 |
On Wed, 8 Feb 2017 16:04:30 -0500, rickman <gnuarm@gmail.com> wrote: >On 2/8/2017 12:08 PM, Jeff Liebermann wrote: >> On Wed, 8 Feb 2017 05:24:35 -0500, rickman <gnuarm@gmail.com> wrote: >>> Yes, but *how* do they run the grid faster or slower? Also, *who* >>> controls this? >> >> This is cool. Crowd sourced utility frequency data: >> "FNET/GridEye Web Display. U.S. Frequency Gradient Map" >> <http://fnetpublic.utk.edu/gradientmap.html> (USA/Canada) >> <http://powerit.utk.edu/worldmap/> (World) >> Some detail on how it works: >> <http://fnetpublic.utk.edu> >> <https://en.wikipedia.org/wiki/FNET> >> >> Wikipedia article on Utility Freq: >> <https://en.wikipedia.org/wiki/Utility_frequency#Stability> >> Looks like it's run by the NERC: >> <https://en.wikipedia.org/wiki/North_American_Electric_Reliability_Corporation> >> but I couldn't find anything involving frequency control on their web >> pile. >> >> "How do power plants maintain a 60 Hz frequency?" >> <https://www.reddit.com/r/askscience/comments/1kpx0l/how_do_power_plants_maintain_a_60_hz_frequency/> >> >> My guess(tm) is the actual speed adjustment varies by the generator >> type. For solar, there's a DC to AC inverter which can be controlled >> electronically. For hydro, vary the flow rate to match the load. For >> steam power, vary the steam pressure to match the load. Since both >> the load and the flow/pressure affects the frequency, the steam >> pressure, flow rate, etc will need to track to considerable precision. >> >> There's also a proposal to eliminate the TEC (time error correction): >> "Time Error Correction and Reliability White Paper" >> <http://www.nerc.com/pa/Stand/Project%2020101422%20Phase%202%20of%20BARC%20%20BAL004%20DL/BAL-004-0_White_Paper_Clean_09242015.pdf> > >Thanks for all the links, but they don't actually explain the mechanism >for how the various generators are adjusted to maintain the grid >frequency. Someone else indicated in Europe there is a central point of >measurement and once a day they send out orders to plant operators to >adjust some control that causes the generator to exert force on the >network. I suppose that creates an individually small, but in aggregate >large force to drive the grid frequency. But that has to be separate >from adjusting the generators for the varying loads. When the load goes up, the frequency goes down. To recover, the operators increase generator power which, in turn, increases line frequency. How hard is that to understand?
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