[time-nuts] Re: Power line timing

[Peter Reilley]

On 3/26/2024 3:47 AM, Stefan Hegnauer via time-nuts wrote:
> On 26.03.2024 08:30, Hal Murray <halmurray at sonic.net> wrote:
>> Europe expects electric clocks to keep good time.  Or did a few years 
>> ago when
>> they were off by 6 minutes.  Anybody know if their power companies 
>> are trying
>> to drop that constraint?
>
> The current situation in Europe can be seen here in almost real-time:
> https://www.swissgrid.ch/en/home/operation/grid-data/current-data.html
>
> You may want to scroll to the very bottom of that page. I find the 
> ~150° phase difference between Agios Stefanos (north of Athens, 
> Greece) and Thessaloniki (about 300km further north) interesting ... 
> what are they doing?
>
> - Stefan
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 Â Â Â Â  One thing that can explain phase differences between different 
points on a grid
is VAR production.   VARs (volt amp reactive) are the result of loads 
not being
purely resistive.   Homes tend to be resistive but factories tend to be 
inductive.
A load that is the result of a lot of motors will be inductive. The 
utility must
produce not only the Watts that the grid demands but also the VARs needed.
 Â Â Â  A power plant that produces more VARs on a grid will have a 
constant phase
difference from a plant on the same grid producing less VARs.   A generator
can even produce negative VARs.   This might be called volt amps capacitive
but that term is not used.   Long transmission lines tend to be capacitive.
 Â Â Â  Since VARs are not power they do not require fuel to produce them.
However they do need to be transmitted and transmitting VARs are just as
lossy as transmitting watts.   The locations where VARs are needed does
not overlay well with the locations where Watts are needed.   Thus,
VARs need to flow through the grid in a different pattern then Watts.
 Â Â Â  A particular power plant that is in an industrial area may produce
electricity that is unusually unbalanced.   It may produce many more
VARs than Watts because the local load needs the VARs.   Since VARs
cost money to transmit a utility will strive to generate them locally.