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Slipping Standards: Continental Europe Slows Clocks

posted by martyb on Tuesday March 06 2018, @10:12PM   
from the you're-not-just-bored:-the-wall-clock-IS-slow dept.

pTamok writes:

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.

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Original Submission

• Re:An EE degree doesn't help me... (Score: 3, Informative) by khallow on Wednesday March 07 2018, @04:16PM

  by khallow (3766) on Wednesday March 07 2018, @04:16PM (#649043) Journal

  Not going to take on most of your argument, but due to skin effect [wikipedia.org], you're incorrect on the relative performance of AC and DC in conductors. For example, in copper wire, the skin depth at 60 Hz is 8.5 mm. What that means is that the effective conducting part of a large high voltage wire is just the outer shell (that's for any wire that is more than 1.7 cm thick, such as those used in continental-scale energy transmission) is just that outer shell and you will see increasing impedance per unit area starting around that diameter.
  
  You also have parasitic loss due to eddy currents induced in nearby bits of metal. Polyphase systems [wikipedia.org] can greatly reduce these effects, but they never go away. Doesn't happen in DC lines except when first powering the line up.

  Parent

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