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Topic: AC Voltage & Frequency Monitor Project (Read 7 times) previous topic - next topic

Bookworm

#5
Feb 22, 2012, 10:07 pm Last Edit: Feb 22, 2012, 10:22 pm by Bookworm Reason: 1
The changing frequency of the mains supply is not "Manipulated" in order to keep clocks accurate.
It's caused by an imbalance between supply and demand and the generating / distribution companies have a minute by minute battle to keep the frequency within it's declared value.

There is no way to store electricity in the grid, supply has to match demand. But adding or removing power from the grid is not instant. Turbines have to speed up or slow down, fuel rods have to be added or removed etc.

A good analogy is riding a bycycle. If you are on perfectly flat track you can keep a perfectly constant speed. If there is a hill up or down then the demand on your legs goes up or down, and so does your speed, unless you are really good at matching your effort with the gradient. As you go up a hill you will slow a little as you pedal harder to bump your speed up. and vice versa.

In the UK we have "TV Pickup" when soap operas finish we all go and put the kettle on (1.75 Million kettles in under 5 minutes that's 3 Gigawatts extra). Its such a big surge, and the frequency drops so fast we have to get more in from France!
http://www.youtube.com/watch?v=fAhgjhrDBvo
our "National Balancing Engineer" braces himself, and the grid, for the end of Eastenders (TV soap opera) and sweats a bit when it's late and France lets us down. Watch him go quiet when the end theme tune (Drums. Dum Dum Dum diddiddy) starts.

Great project BTW.

And...  What a good day to be posting about it. Heinrich Rudolf Hertz's 155th Birthday.
Bookworm

Chagrin


Techone

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What a good day to be posting about it. Heinrich Rudolf Hertz's 155th Birthday.


Hum...I did know about that little detail.   :~

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Its such a big surge, and the frequency drops so fast we have to get more in from France!


That is interresting !!!. In Canada, the extra need power came from the US.  I did not know UK depand on France or Europe for the extra power.  In 1759 , In Canada, French and English where fighting each others... just pointing this out.
http://www.ask.com/wiki/Battle_of_the_Plains_of_Abraham  ...  :D  

Thank for the comment and the U-tube link.

Right now, it still a work in progress. My project will work in the UK. You just need the proper transformer secondary Voltage output. Beside, you can change the value of the AC voltage input of the circuit by increasing or decreasing R5, R6, R4 and VR1 for a proper Vout at IC2A out pin.


   


Techone

@Chagrin

I just hope this "experiment" will not affect the Canadian electrical system. Maybe an "out of phase" problem may occur.

Bookworm

If one were to construct your instrument for use in the UK  the accuracy of your measurements could be checked against that of the grid.

http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm

I don't know if there is something similar in Canada or USA.

BTW The UK has electrical connections to France, Northern Ireland, the Isle of Man & The Netherlands.


Bookworm

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