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Comments on this concept

Discussion in 'Alternative Energy' started by Mikebits, Feb 12, 2009.

  1. Mikebits

    Mikebits Well-Known Member

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    I have been looking to do some volunteer work to better improve my contact list. I found this organization that is in need, but the mission statement of this place left me unsure of how viable the plan is.

    GENI - Global Energy Network Institute

    Since I would be working as a researcher/writer I think I would truely need to believe in what I was doing, and at this point I shake me head with doubts.

    Any thoughts on this place? Are they just idealistic dreamers with an unrealistic vision?

    1. Paris, L. [et al.], "Present Limits of Very Long Distance Transmission Systems", CIGRE International Conference on Large High Voltage Electric Systems, 1984 Session. Section 8. Conclusions.
    2. ". . . transmission systems can be set up over a distance of as much as 7000 km in d.c. and 3000-4000 km in a.c. . . . as to make advantageous the exploitation of those sources . . ."
    Any comments on this claim I was not aware that Long distance DC transmission has ever really been considered.
    I was also reminded of the 19th century battle of currents. Edison and Westinghouse.
    George Westinghouse and the Battle of the Currents (Electrical Apparatus, 10/03)
     
    Last edited: Feb 12, 2009
  2. duffy

    duffy New Member

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    You've never heard of HVDC? They use it in the country I grew up in - Appalachia.

    You're in for a treat.

    1.) Widipedia HVDC.
    2.) Google image search "valve hall"

    Whoa.
     
    • Like Like x 1
  3. JBrock

    JBrock Member

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    It makes a lot of sense, but you are more likely to end up on one side of a political power battle. Last time around, they stomped down Tesla.
     
  4. dave

    Dave New Member

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  5. Mikebits

    Mikebits Well-Known Member

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    I will check that out, thanks.
     
  6. Mikebits

    Mikebits Well-Known Member

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    High-voltage direct current - Wikipedia, the free encyclopedia

    It seem the big pitfall is the conversion from high voltage to lower voltage which I suspected. But I think I must read more. Very interesting indeed. Thanks again for the tip. So this is doable. Wow.
     
  7. duffy

    duffy New Member

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    Dude, did you look at the VALVE HALLS? Those are humongous SCR's!

    What's about the LAST electronic switching device you would think would be used to convert DC into AC? An SCR!
     
  8. Mikebits

    Mikebits Well-Known Member

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    Embarrassed to say I did not look that one up yet...
     
  9. Mikebits

    Mikebits Well-Known Member

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    Oh you mean something like this?
    [​IMG]
     
  10. duffy

    duffy New Member

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    Nobody is allowed in the building when it's running or you'll DIE! Horribly, I'm sure, though I have not found a reference to exactly what kills you.

    And at the heart of it is a simple LC tank circuit driven by an SCR. There's a coil in series with the line, and a capacitor to ground, SCR fires on, cap charges through coil, when the peak voltage on the cap is higher than the line potential, current eventually tries to reverse, SCR switches off, cap discharges (through a transformer), cycle repeats.

    Well, sometimes the capacitor is a synchronous condensor and looks more like banks of motors, and the SCR is really fifty-zillion littler SCR's living in Thyristor Towers apartments there, the coil appears to have been designed by Oudin on Mt Olympus... but it comes down to a basic tank circuit and a switch.
     
  11. Hero999

    Hero999 Banned

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    Duh, you get electrocuted don't you?

    I didn't know that.
     
    Last edited: Feb 13, 2009
  12. notauser

    notauser New Member

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    Well AC kills dogs and elephants, so it might be a good idea..:)
    I was truly under the belief that AC is by far the better way to transmit power..
     
  13. kchriste

    kchriste New Member Forum Supporter

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    Using DC eliminates the skin effect losses in long transmission lines. Resistive losses remain.
    They also use DC for underwater cables as the insulation doesn't have to be as thick. (Think RMS vs Peak)
     
    Last edited: Feb 13, 2009
  14. mneary

    mneary New Member

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    AC can use transformers, which is convenient where insulation thickness and wire diameter are less of a factor (like local and semi-local transmission).

    But as stated DC is better where lots of power has to go a long distance (interstate and international).
     
  15. Nigel Goodwin

    Nigel Goodwin Super Moderator Most Helpful Member

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    It is - because it's simple and reliable, DC is far too complicated and expensive to convert.
     
  16. bryan1

    bryan1 Well-Known Member

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    Mike the transmission run from Tasmania to Victoria here on Oz is HVDC. There was an article in silicon chip mag on it and it is impressive, the valve hall uses the new generation light sensor SCR's. You might want to check that one out if your unsure of HVDC

    Cheers Bryan
     
    Last edited: Feb 14, 2009
  17. Hero999

    Hero999 Banned

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    duffy,
    Do you have a schematic of the inverter described in your previous post?
     
  18. Roff

    Roff Well-Known Member

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    Another example of HVDC is the 3100 megawatt capacity, 1,362 kilometer (846 mile) Pacific DC Intertie from the Washington-Oregon border to the Los Angeles, California area in the US.

    EDIT: It is included in the Wikipedia HVDC article Projects List.:eek:
     
    Last edited: Feb 15, 2009
  19. duffy

    duffy New Member

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    Yes, and you probably did too if you searched - but you might not have realized the thing you were looking at was bidirectional. They usually show it from left-to-right as the rectifier:

    The ABB Group: HVDC technology

    - but it works both ways. The operation is similar to a regenerative brake in motor control systems that use brushless multipole AC motors running off batteries.
     
    Last edited: Feb 15, 2009

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