On 02/05/13 10:17, Dave Liquorice wrote:
On Thu, 02 May 2013 09:40:07 +0100, The Natural Philosopher wrote:

Frequency is less important now than it was as there are fewer timing
devices rely on it.
Tell that to the German factories running synchronous motors that are
having f to intsall massive UPS/inverters because sudden fluctuations
in the mains frequency due to sun coming out/wind gust coming along are
destroying the machines the motors drive.
So 2 GW can drop off the euro frequency zone and produce a 0.05 Hz change
in the frequnecy but a few wind mills or photo voltaics can shove the
frequency out of spec?
do you know how MUCH solar energy is n germany. IIRC its about 30GW
capacity, and it goes on a sunny summers day from 30GW to the square
root of **** all when the sun sets.

http://en.wikipedia.org/wiki/Solar_power_in_Germany

Its not a few windmills or photovoltaics. Its MASSIVE. So MASSIVE they
ae having to buld 20 coal fired power stations to back it up, all of
whch will be powered up and running all day to cope with the MASSIVE
drop off at sunset.



If the factory motors or machinery can't handle within supply
specification frequency variations there is something wrong with them.

They can. But the German grid is incapable of keeping TO that
specification. They are talking of relaxing the specification. Worse, is
not the actual amount of variation, its the speed with which it happens.
the grid is upping and downing frequency and power wise over period in
the *seconds* range. Beyond the ability of even hydro to compensate for.

Ad the reason is not hard to see. In spinning turbines of large
dimensions in conventional power stations there is enough energy on the
inertia of the rotors to smooth out any massive sudden loads. And demand
fluctuates smoothly - yes you get the odd blip when everybody swtches on
a kettle after coronation street, But that only happens one a day and
all te pwoer here is from conventional power stations.

Inverters have no inertia. Solar panels and windmills fed through
inverters have zero storage. so the possibility of sudden and massive
swings in frequency is built right in.

fluctuating demand is a bad enough issue to cope with without compunding
the problem by adding very fast acting massive capacity of unpredictable
intermittency on to it.

Its so bad the Czechs have indicated that they may disconnect from the
German grid if it gets worse.

I am not making this up, its well documented.



Or are you saying, counter to what everyone says, the bit of the Euro
frequency zone in Germany can alter in frequency relative to the rest?



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Ineptocracy

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