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from the you're-not-just-bored:-the-wall-clock-IS-slow dept.
Electric clocks on continental Europe that are steered by the frequency of the power system are running slow by up to 5 minutes since mid-January according to a news release from the European Network of Transmission System Operators for Electricity ('entsoe'). The transmission system operators (TSOs) will set up a compensation program to correct the time in the future.
Many electric clocks rely on the transmission system frequency to provide a source that minimises long-term drift. Quartz crystals have good short term stability, but dreadful long term stability, so plant and machinery that requires power to be turned on or off at a specific time each day without maintenance over a long period historically used clocks slaved to the power-system frequency, which is kept long-term stable by the system operators to prevent problems in power generation and transmission across national and supra-national grids - for example, attempting to switch supplies to generators that are not synchronised to the grid frequency can severely damage the generator.
It is normal for transmission system operators to allow the frequency to drop slightly at periods of high demand, thus slowing clocks, but usually, the frequency is increased during periods of low demand to ensure the long-term average frequency remains stable.
(Score: 2) by frojack on Tuesday March 06 2018, @10:25PM (3 children)
I wonder what affect increasing reliance on Wind generators have on maintaining a grid frequency standard.
Solar, (I suspect) can simply sync to the grid since it is faking AC anyway, but wind turbines are running complex machinery that runs at a speed dictated by the wind. They have a lot of electronics trying to match the grid, but the wind pays no heed.
https://www.quora.com/Do-wind-turbines-produce-DC-or-AC-current [quora.com]
No, you are mistaken. I've always had this sig.
(Score: 0) by Anonymous Coward on Wednesday March 07 2018, @09:01AM
It's been a while, but I remember that wind generators generate AC at unstable frequency. Which is why they transform that unreliable AC signal to DC and from DC back to grid AC.
This is from years back, may not be true for all manufacturers or maybe a better method is found meanwhile or ...
(Score: 0) by Anonymous Coward on Wednesday March 07 2018, @09:38AM (1 child)
Just a hunch but I would expect hydro have all the same issues as wind. And that's among the oldest power technologies we have.
(Score: 3, Insightful) by anubi on Wednesday March 07 2018, @10:44AM
Mostly you have a big lake of water behind you, at constant pressure, and you can control your penstocks, which govern the energy you can put into the system.
So, the line frequencies and voltages to wobble a bit, in response to changing loads. And if things get too out of control, circuit breakers all over the place trip and you have to restart the system, aka, blackout.
The total number of cycles on the line are counted, and at 60Hz, we should get 60*3600*24 of 'em per day. If we lose some, they make up for them. If they give us extras, they can slow things down a bit. But over the long term, you should never have to correct your electric clock. This started in the early 1900's.
These clocks were known as "Telechron" [wikipedia.org] clocks. They came in damn near every oven sold, along with radios and all sorts of other appliances. America depended on the power companies to keep all the clocks on time. Or at least kept 'em all synchronized.
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]