Turbine generators turn at a regulated frequency, and even 100+ years ago they must have kept it somewhat close to optimum, probably using a mechanical regulator. When did they start doing it with precision in the expectation that customers would depend on it as a time base?
In the UK I suspect it is still an official secret.
Basically once there was a standardised UK National Grid the NPL were tasked with providing the time signal information to allow the operators to maintain long term average frequency stability (and voltage too).
Traffic lights with rush hour bias and synchronous motors relied on it so I expect that will put a bound on when they first started doing it. Used to annoy astronomers since in mid winter the frequency would be noticeably higher during low load times after midnight. Synchronous drives would therefore run fast and require more manual guiding.
Today they are all on stepper motors locally clocked or DC servos (and any worthwhile scope will have an autoguider - even amateur ones).
I'd expect that all of europe and UK and Ireland are phase-locked these days. I wonder how far that extends. Russia? India? China?
Possibly all the links are DC.
Europe only, AFAIK.
No.
I can't tell you when they started maintaining power frequency, but Google surely can.
In the US, the grid is no longer required to be maintained for time keeping.
In the past, rather than running at a fixed frequency, which would have been very difficult, the time was tracked and frequency deviations were made up by running the opposite for a while. The goal being that electric clocks would not drift, other than a few seconds each way.
With the widespread adoption of time pieces regulated by quartz oscillators, the need for electric clock accuracy became less significant. The electric power providers pushed to eliminate this process of making up time and now only adhere to a, not so tight, frequency specification.
Since they reduced the requirements for power line frequency stability I have been checking my electric clock against my wrist watch which is radio controlled*. For the last year or two my electric clock has been holding to the correct time within in less than 30 seconds per day. That is there is a window of less than 30 seconds that it stays within. It may change more than 10 seconds in any one day, but it hasn't strayed outside of that 30 second window. I have not had to reset the clock in that time.
So the US power line frequency is very good long term, but not so great short term.
Bill
*The National Institute of Standards and Technology (NIST) has a radio station in Boulder, Colorado which broadcasts the official time and frequency continuously. A radio controlled watch (or clock) receives this signal and corrects the watch at regular intervals. The time on such a watch is therefore extremely reliable.
One very common thing are timers running a synchronous motor with gears, and plastic ticks to switch the power on or off periodically for anything.
Are there undersea links, UK to europe, that are AC?
"Atomic" refers to the clocks at the WWVB facilities. The time transmitted by WWVB uses atomic clocks to keep the time.
Such timers typically maintain a very slack time. The mechanical trips are not at all very precise, set to the minute at best. They are also subject to time slips on power failures.
I'm not sure.
AFAIK DC is preferred for undersea or underground c Is the UK power grid connected to Europe? As of 2023, National Grid operates five interconnectors, connecting the UK with France, The Netherlands, Belgium and Norway. Our sixth interconnector, Viking Link, is currently under construction and will join the UK with Denmark.
What are electricity interconnectors? | National Grid Group
They do not say if all are DC. The last one, North Sea Link (NSL), is.
The UK grid is connected to adjacent European electrical grids by submarine power cables at an electricity interconnection level (transmission capacity relative to production capacity) which was 6% as of 2014. As of 2022, the total capacity of these connectors is about 7.7 GW.
National Grid (Great Britain) - Wikipedia Wikipedia
Interconnectors
There is a 40 MW AC cable to the Isle of Man, the Isle of Man to England Interconnector.
The UK grid is connected to adjacent European electrical grids by submarine power cables at an electricity interconnection level (transmission capacity relative to production capacity) which was 6% as of 2014.[39]
As of 2022, the total capacity of these connectors is about 7.7 GW.[citation needed] They include direct-current cables to northern France (2 GW HVDC Cross-Channel, 1 GW HVDC IFA-2, 1 GW ElecLink via the Channel Tunnel[40]); Belgium (1 GW HVDC Nemo Link); the Netherlands (1 GW HVDC BritNed); Norway (1.4 GW HDVC North Sea Link); Northern Ireland (500 MW HVDC Moyle Interconnector); and the Republic of Ireland (500 MW HVDC East–West Interconnector).
A link is under construction to Denmark (1.4 GW Viking Link) which is due to be completed in 2023. A further 500 MW link with the Republic of Ireland (Greenlink) is scheduled for 2024.[41] Further potential schemes include links with Germany (NeuConnect, 1.4 GW); Iceland (Icelink, around 1 GW)[42] and Morocco (3.6 GW from new battery-backed solar generation).[43]
So the one to the Isle of Man is AC, the rest appear to be DC.
But you asked initially about "all of europe and UK and Ireland"; the land connections in most of the EU are AC, AFAIK.
Most of Continental Europe is in a single synchronous network. CIS (Russia etc.) have their own network. UK has their own network as well as Scandinavia.
In the Scandinavian net, the frequency normally varies between 59.9 and 50.1 Hz depending on loading changes.
There are HVDC links between all these networks.
Typo? It is 49.9 to 50.1 Hz.
Yes, 50 Hz DC. Sure, why not?
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