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Science Forum Index » Physics Forum » Why Is DC Power Transmission 10X More Efficient Than AC?
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| Bret Cahill |
 Posted: Tue Apr 22, 2008 9:13 am |
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Is there some low frequency radiation or hysterisis loss or what?
Bret Cahill |
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| JeffM |
| Posted: Tue Apr 22, 2008 9:44 am |
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Bret Cahill wrote:
:10X More Efficient
Cite your sources for 920% efficiency. |
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| Benj |
| Posted: Tue Apr 22, 2008 12:05 pm |
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On Apr 22, 5:32 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:
Quote: "Dope Bowey"
"JeffM"
Bret Cahill wrote:
:10X More Efficient
Cite your sources for 920% efficiency.
Cite where you think he said that. It's not in this thread.
** What is 10 times more efficient than 92 % ??
920% ?
The OP's question is an absurd troll.
Like you.
...... Phil
Are modern "scientists" really this dense? Ten times efficient isn't
920%! What you must have just graduated from a "modern" high school?
Dig. If standard transmission is 92% efficient, then that means there
is 8% of the energy lost. TWICE as efficient would only have 4% of the
energy lost or would be 96%. The interested student can take it from
there...
Since 10X would be more than 99% efficient I am somewhat skeptical
that even modern converters can produce so little loss. |
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| Bret Cahill |
| Posted: Tue Apr 22, 2008 12:13 pm |
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Quote: :10X More Efficient
Cite your sources for 920% efficiency.
Cite where you think he said that. �It's not in this thread.
** What is 10 times more efficient than 92 % ??
Going 10X further with the same 8% loss?
One tenth as lossy for the same distance?
And who mentioned 8%?
Bret Cahill |
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| Bret Cahill |
| Posted: Tue Apr 22, 2008 12:16 pm |
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Quote: Is there some low frequency radiation or hysterisis loss or what?
Where do you get your inital incorrect idea from ?
Europeans claim they can run a DC power line from solar thermal fields
in the Sahara thousands of kms to N. Europe.
Bret Cahill |
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| tadchem |
| Posted: Tue Apr 22, 2008 2:11 pm |
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On Apr 22, 6:05 pm, Benj <bjac...@iwaynet.net> wrote:
Quote: On Apr 22, 5:32 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:
"Dope Bowey"
"JeffM"
Bret Cahill wrote:
:10X More Efficient
Cite your sources for 920% efficiency.
Cite where you think he said that. It's not in this thread.
** What is 10 times more efficient than 92 % ??
920% ?
The OP's question is an absurd troll.
Like you.
...... Phil
Are modern "scientists" really this dense? Ten times efficient isn't
920%! What you must have just graduated from a "modern" high school?
Dig. If standard transmission is 92% efficient, then that means there
is 8% of the energy lost.
That's 8% INefficiency
Quote: TWICE as efficient would only have 4% of the
energy lost or would be 96%.
Your 4% would be HALF as INefficient; not at all the same thing.
10 x 92% is still 920%.
Quote: The interested student can take it from
there...
Since 10X would be more than 99% efficient I am somewhat skeptical
that even modern converters can produce so little loss.
Tom Davidson
Richmond, VA |
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| Jan Panteltje |
| Posted: Tue Apr 22, 2008 2:22 pm |
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On a sunny day (Tue, 22 Apr 2008 12:13:06 -0700 (PDT)) it happened Bret Cahill
<BretCahill@aol.com> wrote in
<98d0c415-606a-4d10-8158-1ee67568e4e6@26g2000hsk.googlegroups.com>:
Quote: Is there some low frequency radiation or hysterisis loss or what?
Bret Cahill
It all depends, AC has inductive losses, and capacitive losses between lines.
DC can be efficient at very high voltages, where the current is low,
as losses in the wires are i^2.R, but requires big solid state AC/DC and DC/AC
converters at each side.
http://en.wikipedia.org/wiki/Electric_power_transmission
Here is one example where DC is used:
http://en.wikipedia.org/wiki/Pacific_DC_Intertie |
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| Don Bowey |
| Posted: Tue Apr 22, 2008 3:00 pm |
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| Eeyore |
| Posted: Tue Apr 22, 2008 3:18 pm |
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Bret Cahill wrote:
Quote: Is there some low frequency radiation or hysterisis loss or what?
Where do you get your inital incorrect idea from ?
Graham |
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| Phil Allison |
| Posted: Tue Apr 22, 2008 4:32 pm |
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"Dope Bowey"
"JeffM"
Quote: Bret Cahill wrote:
:10X More Efficient
Cite your sources for 920% efficiency.
Cite where you think he said that. It's not in this thread.
** What is 10 times more efficient than 92 % ??
920% ?
The OP's question is an absurd troll.
Like you.
....... Phil |
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| Don Bowey |
| Posted: Tue Apr 22, 2008 5:07 pm |
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On 4/22/08 2:32 PM, in article 6773rgF2n665eU1@mid.individual.net, "Phil
Allison" <philallison@tpg.com.au> wrote:
Quote:
"Dope Bowey"
"JeffM"
Bret Cahill wrote:
:10X More Efficient
Cite your sources for 920% efficiency.
Cite where you think he said that. It's not in this thread.
** What is 10 times more efficient than 92 % ??
920% ?
The OP's question is an absurd troll.
Like you.
...... Phil
Gee, thanks phil. |
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| John Larkin |
| Posted: Tue Apr 22, 2008 5:17 pm |
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On Tue, 22 Apr 2008 12:13:06 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:
Quote: Is there some low frequency radiation or hysterisis loss or what?
Bret Cahill
If you mean long-distance transmission lines, DC can be run at higher
average voltages (less corona losses, relatively) and has no skin loss
or inductive coupling to the world. I don't know about 10:1.
DC systems do need inverters and rectifiers on the ends, which have
losses.
John |
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| Paul E. Schoen |
| Posted: Tue Apr 22, 2008 5:21 pm |
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"Bret Cahill" <BretCahill@aol.com> wrote in message
news:98d0c415-606a-4d10-8158-1ee67568e4e6@26g2000hsk.googlegroups.com...
Quote: Is there some low frequency radiation or hysterisis loss or what?
The losses in electrical transmission have increased from about 5% to 9.5%
in recent years, so efficiency is 90.5% to 95%.
http://www.energetics.com/gridworks/grid.html. There is a nice overview at:
http://www.energetics.com/gridworks/pdfs/factsheet.pdf
According to http://en.wikipedia.org/wiki/Electric_power_transmission,
power losses were about 7.2% in 1995. And according to
http://en.wikipedia.org/wiki/High-voltage_direct_current, HVDC transmission
losses are about 3%. So a tenfold increase in efficiency seems
unreasonable.
I would assume that a tenfold increase in efficiency would be a tenfold
reduction in losses, so the present 7.2% would be 0.72%, for 99.3%
efficiency. That is very likely impossible outside of laboratory
conditions, and would probably require impractical amounts of copper, or
cryogenic means to achieve superconductivity, which would itself require
power and reduce overall efficiency.
But in direct answer to your question, there is a substantial amount of
radiated energy loss with AC that does not occur with DC. But open air DC
transmission lines do have losses in the form of a flow of ions, and both
AC and DC have losses due to corona.
Paul |
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| Eeyore |
| Posted: Tue Apr 22, 2008 5:40 pm |
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Bret Cahill wrote:
Quote: Is there some low frequency radiation or hysterisis loss or what?
Where do you get your inital incorrect idea from ?
Europeans claim they can run a DC power line from solar thermal fields
in the Sahara thousands of kms to N. Europe.
No they don't.
Graham |
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| Phil Allison |
| Posted: Tue Apr 22, 2008 6:53 pm |
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"Benj"
Quote:
The OP's question is an absurd troll.
Like you.
Are modern "scientists" really this dense? Ten times efficient isn't
920%! What you must have just graduated from a "modern" high school?
Dig. If standard transmission is 92% efficient, then that means there
is 8% of the energy lost. TWICE as efficient would only have 4% of the
energy lost or would be 96%. The interested student can take it from
there...
** WHAT COMPLETE BOLLOCKS !!
...... Phil |
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