Slashdot Mirror
Frequency Deviations In Continental Europe Are Causing Electric Clocks To Run Behind By 5 Minutes (entsoe.eu)
elgatozorbas shares a short note from the European Network of Transmission System Operators for Electricity (ENTSO-E): Apparently the Continental European Power System has been off since mid-January, causing some clocks to run behind by 5 minutes. How common are these mains-frequency synchronized clocks anyway, and why are they built that way? "The power deviations have led to a slight drop in the electric frequency," reports ENTSO-E. "This in turn has also affected those electric clocks that are steered by the frequency of the power system and not by a quartz crystal... All actions are taken by the transmission system operators (TSOs) of Continental Europe and by ENTSO-E to resolve the situation."
The reason they did that is because an AC synchronous motor was much cheaper than a quartz oscillator and solenoid like the new ones have.
-- You are in a maze of little, twisty passages, all different... --
Wait... 5 more minutes.
Many phono turntable motors also sync with the mains frequency. I think all the good turntables allow you some speed adjustment but this would still be troublesome.
A quartz crystal has excellent short-term accuracy, but lousy long-term accuracy.
Using the AC mains as a frequency reference works well if the power companies handle things correctly: during the day when demand is high, the mains frequency is not well-controlled and the clocks drift slightly. However, the power company is supposed to keep track of this, using some other precise time reference, and then adjust the mains frequency at night to compensate for whatever got screwed up during the day.
When done right, this results in excellent long-term accuracy for clocks that use this method, because the power companies handle all of the necessary corrections. But without the right corrections, AC mains are a terrible frequency reference.
If two sources don't agree on a frequency (and in phase) there is going to be power transfer between the sources. That's why everyone has to agree.
who advertise faster speeds than they deliver, the electric utilities are now doing the same. delivering less Hz than advertised.
amazing that greedy american utility companies didn't think of it first.
OP sounds like an idiot. Think for a second, how would you build an accurate motor driven clock? If the mains frequency is accurate then it's pretty easy. Nearly every electric clock built in the last 100 years runs this way. Not until integrated circuits became common did they use crystals. Even then accurate crystals aren't cheap and vary with temperature.
Only the State obtains its revenue by coercion. - Murray Rothbard
.
So the timing of the US power grid was kept in quite good sync. Long-term accuracy of those AC-sync'd clocks were in the range of a a second or two per year. Back in the late 1900's, that was very good for your basic, inexpensive living room clock. (seems funny to write, "late 1900's")
It's TECHNICAL English. Do you speak it?
-- You are in a maze of little, twisty passages, all different... --
Here's a bit more about what AC is referring to. AC electricity switches from positive to negative 50 (or 60) times per second. Imagine two power stations that are interlinked. If both send positive at the same time and both send negative at the same time, they can share the load. If one sends negative while the other sends positive, they'll cancel each other out. The grid becomes a short circuit between the two generators.
In order to have an electric grid, to have many power stations interconnected, they all need to switch from positive to negative at exactly the same time. The easiest way to have them all running in sync is to agree they'll all run at exactly 50 Hz. That establishes the frequency of the grid as a whole. Then if one generator is slightly ahead of or behind the grid it can sense the difference and speed up or slow down as needed.
So an accurate AC frequency is needed in order to have the grid work right. Since the frequency is already accurately controlled for grid requirements, clocks may as well need make use of it.
In the last year or two grid operators have starting allowing the frequency to vary a bit more than they used to. This is needed where wind power makes up a significant percentage of generation because wind is gusty. Wind is a cheap source of power, but very different from traditional methods and not nearly as controllable / predictable, so the grid has to adapt to the idiosyncrasies of wind.
Because this is how you cause massive power-grid failure.
OMG facts!
Mains frequency is normally very stable long term.
Have a look here http://jorisvr.nl/article/grid...
I would say, because of all the new renewable energy providers, it has been a much more difficult job to synchronize every body.
Imagine you have a 10 ton flywheel in front of you and it is rotating at 49.9 times per second but you want it to be 50, and there are 300 little motors all driving the flywheel. Your job is to now coordinate everybody to match 50Hz, but where the load on the flywheel varies minute to minute. In the old days, big old power stations could slowly influence this average frequency, but now there are hundreds of windmills and solar inverters and gas turbines and nuclear and coal, all with their unique issues.
46137
That Hertz!
In America, Ft. Collins, CO, has a 50K watt radio broadcast from an atomic clock. This keeps all clocks that want to be, synced up correctly. It is something that all continents should do. 1-2 radios per continent would solve this.
I prefer the "u" in honour as it seems to be missing these days.
I had a digital alarm clock given to me when I was 5 years old (1978). I had it until I was ~24. It kept absolutely perfect time from 1978 until 1992, when I went off to college. Iowa State University has its own power grid and power plant. The two years I lived in the dorms on-campus, my alarm clock gained 5 minutes PER WEEK. (Yes, PER WEEK.) I got in the habit of setting it back five minutes every Sunday. I wore out the minute-advance button in those two years, fixed it a couple of times with a soldering iron. 1994 I moved off-campus and got an apartment, and boom, clock worked perfectly again, only set it twice a year for daylight savings. I asked around the engineering department and several people said, yea, ISU's power plant doesn't sync to the city's grid. I've taken apart a lot of things in my life. I've seen tons and tons of clocks' innards. Many of the mechanical ones have synchronous motors, and gearing ratios that completely and totally depend on the power grid being exactly 60Hz. It's been like that for much of the 20th century (one of the clocks I took apart was from the 1950's).
In software, good programmers learn not to rely on undocumented side effects, because they can change with time and cause strange bugs.
The ability to build a timekeeping device based on AC oscillation is like an undocumented side effect. The grid wasn't built for keeping time. It just (usually) happens to do so.
If you want accurate timekeeping, use a method that is designed specifically for the purpose, like quartz crystals.
.. has been wrong a lot. But likely (much) longer.
Apparently, it is much more harder to maintain the correct number of cycles a day with DC sources like some wind and solar.
Only for you as a user of a private DC power system owner/user.
- If you have a DC supply, you have to come up with an accurate time reference built-into, or driving, your clock.
- If you have mains power (and your supplier is on the ball, unlike these European companies), your big power company has access to a good clock (like listening to the United States National Institute of Standards and Technology's (NIST) time reference broadcasts and adjusting the frequency to keep it totalling the right number of cycles per day on the average. (This is easy: Just hang a sync-motor electric clock across the mains and tweak frequency now and then to keep it on time.) Just as expensive, but the power company does it ONCE and keeps ALL THEIR CUSTOMERS' clock on speed.
- If you have a DC system and an inverter, either the inverter is synchronized by something accurate or your synchronous-motor clocks will drift.
I think AC grid power systems have been doing this since Tesla/Westinghouse first started setting them up. It was one of AC's selling points in the Tesla/Edison AC/DC utility wars.
Nowadays, though, WWV transmits an atomic-clock referenced time code signal on a 60 kHz VLF carrier that's detectable anywhere in the US at some time during pretty much every day. Inexpensive clocks are available that use a crystal for the basic timing (achieving accuracies of a fraction of a second per day) and using the radio time signal to resynchronize when available (to avoid accumulating a drift). So a wall clock running on a battery can now do better than a synchronous-motor clock running on the mains.
(Your typical electronic bedside alarm clock, though, doesn't include the WWVB radio. Instead it runs its timer by counting the cycles of mains power, achieving the same long-term accuracy as a sync-motor clock. If it has a battery and crystal oscillator it only uses them to keep (decent) time during power outages.)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Why
Because this is an easy way to maintain a very accurate long term time base. Particularly since it was developed back in the 1940's and 1950's. Before we had GPS and automated WWV clock synchronization would have required a large and complex receiver system.
Over a short period of time, the grid frequency might drift a few tenths of a percent up or down. But on a daily basis (usually at night) the system operators will add or remove some generation from the grid, speeding it up or slowing it down. The total number of cycles (at 60 Hz in the USA, 50 Hz in Europe) over a day was corrected to match a precision time base counter.
it fluctuates by up to 5%
That's a bit high for my part of the grid. We had underfrequency load shedding set to begin dropping non critical loads (like rural circuits) at 59 Hz.
Have gnu, will travel.
Related:
In 2011 the US did a yearlong experiment : "The group that oversees the U.S. power grid is proposing an experiment would allow more frequency variation than it does now without corrections"
https://phys.org/news/2011-06-...
As noted in the comments, this would affect devices such as phonographs, VCR's tape players, some bar heaters and some clocks. As far as I can tell, the experiment was conducted because:
https://www.energy.gov/sites/p...
POWER SYSTEMS MUST HAVE ADEQUATE FLEXIBILITY TO ADDRESS VARIABILITY AND UNCERTAINTY IN DEMAND (LOAD) AND GENERATION RESOURCES
I recall reading that the regulation of these cycles can cost 1% of the power supply used (sorry, can't find the source link). Another reason for the deregulation may be this:
https://phys.org/news/2006-05-...
Big names pony up for power-line broadband
Current Communications announced Thursday it had received $130 million in investments to accelerate Broadband over Power Line technology. Current uses BPL technology to provide broadband service that runs across power lines, allowing the potential for a new source of retail Internet service as well as accommodating "smart grid" electric meters for utility companies.
"This technology provides utilities with a more intelligent, real-time and secure power grid that should help conserve energy, reduce electricity disruptions and protect critical infrastructure," said Alex Urquhart, president of GE Energy Financial Services.
Now this brings up the question of where the Internet gets it's time from....I'm sure there are a lot of DIFFERENT answers.
It gets it from Wikipedia until someone deletes the article on time then it falls back to GPS, WWVB followed by a sneezium counter in some random trolls basement.
If none of that's available ALL of the Internet slaves their NTP off my stratum 0 sun dial.
You forgot the mandatory: :P
"Motherfucker!"
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
20 years ago the frequency of A.C. in the U.S. was regulated to within about one part in 10^7 according to the IEEE. Not sure what mechanism they used to do that. That's an impressive number.
Circle the wagons and fire inward. Entropy increases without bounds.
Just synchronize them to the French grid frequency.
In English : Swissgrid -> frequency
You did a great job further explaining the last sentence you quoted from me "Then if one generator is slightly ahead of or behind the grid it can sense the difference and speed up or slow down as needed."
That of course doesn't define the frequency the grid should run. For a very small grid, as can often be found in less developed countries, the grid may be only a very few power stations, so the "right" frequency isn't as stable as it is on the primary grids in the US. In the degenerate case of two generators, there's absolutely nothing that makes them converge to the right frequency. They'll converge, but to some random frequency.
Where smaller facilities are located far from industrial centers and feed through a relatively small line (think wind), the local condition after impedance is considered is not unlike the two-generator case.
They're doing everything! At once!
The only clock I have the relies on this is the one in the stove. And it's too fast, yes.
All other clocks are either sync'ed by NTP (macOS, iPhone, Linux/BSD) or directly via radio (long wave receiver).
Windows 2000 - from the guys who brought us edlin
But the cheaper "quartz china clocks" leave out the pricey part to save a few cents per unit and the time spent tuning it.
This *Europe* you're talking about. With a tendency to love over-engineered solutions (specially the german part of it).
Since the late 70s we we actually have a standard for automatically seting clocks : DCF77, and since the 80s radio-controlled clocks have been raising in popularity (I still have one from early 90s).
This things will automatically self-adjust every hour if they can manage to catch the signal. And the whole system is at worse a few seconds off.
No end user needing to fumble with some adjustment screw.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
But 30-40 years ago, the DCF77 standard started to become very popular.
Instead of having clock that still need to be set after a power outage or needs to be set after each daylight saving time change, you have a clock than can auto-adjust it-self hourly over the radio from an atomic clock in Germany, that still works across most Europe (i.e. within the long range radio's reception), is only a few seconds off (the ping time of the radio transmission and electronics processing), and has a notion of DST (so no need to manually move 1 hour forward or backward), and can even work on battery without anything plugged in (it's radio).
And it's German, so nobody will complain that it's tremendously over-engineered as a solution.
At some point in time in the past, TV stations radioemitter could use DCF77 as a source for the clock they broadcast over Teletext/Videotext pages.
"Sufficiently advanced satire is indistinguishable from reality." - [Tips: 1DrYakQDKCQ6y52z6QbnkxHXAocMZJE61o ]
Indeed, the European grid has since they coupled in 1950 a regulator assuring the correct frequency over a 24hr period.
This article is interesting because the system clearly failed and like after the European blackout of 2006 there will now doubt be a further improving of the methods to guarantee a stable frequency.
"The likes of Facebook and WhatsApp are free to those whose privacy is of zero value."
It wasn't really just inertia. The generators also act as synchronous motors. Each ends up loaded more by the grid more when they're getting a bit ahead of the "consensus" frequency and less when they get behind. So once they get synchronized they stay that way. (Barring the occasional screw-up - which usually leads to a regional blackout.)
Also, it explains to people why it takes a while to get the grid back up after a large outage - not only do the generators (properly, "alternators") have to be operating at exactly the same speed to produce the same frequency of power, they also have to be in precise sync as to phase - or you turn hydroelectric dams into very large water pumps!
But if they're heavily loaded they slow down, and if lightly loaded they speed up. They have no inherent absolute speed referenc. So the power companies have to keep them "on time" by comparing them to a good time reference and giving a little extra push (with more steam or whatever) when they're getting behind, less when they're getting ahead - or by lowering the voltage (a brownout) or cutting off parts of the grid (rotating blackouts) when the load is getting too big for them to keep up to speed. If they don't, the generators get slowed down a tad and the clocks slow down. (That's what happened in Europe.)
When I worked for Litton, we worked a lot with generating plants on ships. I got to buy more than a few vibrating reed frequency meters.
The 50/60Hz mains timebase makes an amazing timebase for clocks of all sorts, not just those with synchronous AC motors. It's a dead simple case of taking a sniff of the incoming AC that powers the clock, rectifying it, and then counting the resulting pulse train to drive a display. Virtually everything with a clock and a power cord uses this system.
An hour is divided into 60 minutes (read that as minutes as in small), a minute is divided into minute minutes - second order minute portions of an hour, hence the term seconds. (Thanks to the great and very funny 1910 book Calculus Made Easy by Silvanus Thompson for that gem! See pages 3 and 4.).
Being a natural multiple, 60Hz is a better frequency as a timebase; gearing in mechanical clocks is easier. And our transformers are somewhat physically smaller for the same load than at 50Hz. The effect is peanuts in smaller devices, but in larger equipment it saves a lot of iron and copper.
Fire and Meat. Yummy.
You are thinking of electric clocks connected to a so-called Mother Clock.
That connection was a special cable, not the mains. The last minute before the full hour they synchronised by means of extra pulses.
You would typically find them on train stations and public places.
I have a matched set of 4 of them that came from a warehouse, but they were also common in schools, hospitals, prisons, etc.
The run motor is just a dead-simple 60Hz line-powered clock motor and mechanism with a suicide switch a few minutes before midnight. So, at 11:57 or so, the run motor turns itself off. The master clock operates the set motor to synchronize them, and then turns the run motors back on.
I keep on meaning to build something with a USB port and a couple of relays so that I can use a Linux machine with an NTP client as a master clock for them. Since I don't feel like reinventing the wheel or spending a few grand to buy the real controller, if anyone knows of such a system pre-built, let me know!
Fire and Meat. Yummy.
For our mainframe (1970's) we used an inertia generator that in case of a mains failure would take over until the emergency generator had fired up.
It was a huge steel wheel and although the frequency would fall a bit during the ~5 seconds of the switch over that did not affect the computer.
"The likes of Facebook and WhatsApp are free to those whose privacy is of zero value."
For our mainframe (1970's) we used an inertia generator ...
We had a device called a "motor generator" that did the same thing. It was made by Swineheart, a name I've always found to be ridiculously funny for some reason.
We had no emergency generator; the motor generator was there to let us ride out brief power outages without taking down both Xerox mainframes. As the poster indicates, "brief" meant outages of about five seconds or less. If the outage were longer, the mainframes would lose power.
Circle the wagons and fire inward. Entropy increases without bounds.
"causing some clocks to run behind by 5 minutes"
5 minutes. Per day? Week? Millennium? God, this hurts.
deleting the extra space after periods so i can stay relevant, yeah.
It's trying to get on German time.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
Exactly backwards. Frequency is much better controlled than voltage and always has been. It does drift, but not nearly as much as Voltage does.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
I've been away from home for a week, and when I returned the clocks from my ovens (Samsung and Electrolux) were both 5 minutes behind.
This explains it! I did scratch my head for a while trying to figure out how this could happen.
Line frequency regulation affects the efficiency of the entire power grid, since it's really one gigantic tuned circuit with a center frequency of 60Hz. Get it too far off and power starts being wasted. I'd imagine it could even potentially damage some of the components of the grid if it was too far off for too long.
http://fnetpublic.utk.edu/
Being off frequency causes more serious problems than just clocks being a little off. It is hard on electric motors and other electrical devices and causes electric interties not to work. +-0.5 Hz can cause load shedding and shut down the grid.
Who knows? Maybe Edison was right after all, especially if you think about newer DC power lines that looses less energy in transport.
From the standpoint of long distance power transmission line losses for a given cost of equipment, DC is most efficient and 3-phase polyphase (Tesla/Westinghouse) is the next best.
But for long distance you need high voltage. Before electronics that meant rotating converters. Those limited DC to about 600V, because higher voltages made the commutators arc over. AC, on the other hand, could be easily boosted to tens of thousands of volts (and back down) by transformers.
(There are other advantages to AC, too. For instance, DC is hard to switch off - switches, circuit breakers, fuses - because the arc is driven continuously. In AC the current stops twice per cycle, so if you can clear the ion path before the driving voltage builds up again you're done. Also: The fields around high-voltage DC transmission lines do things like make trees grow toward one of the wires, so they have to be reversed occasionally, while the ground currents from the "ground is one conductor while we work on one of the wires" backup mode can do things like confuse train signals, limiting the currents available in such modes.)
Beginning about the mid 50s, converters to and from high-voltage, high-current DC (using gas discharge tubes) became efficient enough to make DC transmission lines possible. Now we use semiconductors which do better. But the advantage is not all that large, due to the cost of the voltage conversion equipment. So there are only a few, typically very long (so you have only a few converters), DC transmission lines in operation.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way