Power drop on long distance utility lines

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K. W. Hours

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Note to readers: This is a duplicate post that I, also, put out on the "Low Voltage and Limited Energy' Sub-forum (I am advising of this so as to not risk being an annoyance to anyone).
Guys-
Please have patience with this question.... I am merely a fairly new student to the subject of electricity at this point...
When electricitity is being sent along high power ultility lines I have heard that there is "alot" of power drop however I have been unable to learn if there is a general rule of thumb of how much is lost (say, a percentage of current?) per mile.
Can anyone give me some help with this ?
Thanks.
 
tallgirl

tallgirl

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Also, since you've asked about "Power", it depends on the voltage of the transmission lines.

One of the benefits of using higher voltages is that voltage drop depends on the number of amperes flowing through a conductor, and the physical properties of the conductor. If the current (amperes) is halved, so too is the voltage drop. Since power is volts times amperes (more or less -- let's don't confuse the guy just yet :) ), halving the amps and doubling the volts allows the same total amount of power to be transmitted. Doubling the voltage in this manner means the voltage drop will be halved. Since the voltage must be stepped down when it enters a house, the voltage drop is itself halved, making the process even more efficient. The voltage on transmission lines isn't just double what's sent to homes, it's many hundreds, and even thousands of times that voltage.

There's an excellent article in Wikipedia (I reviewed it just now for you :) ) that contains more about the history, etc. of electric transmission.

Electric Power Transmission
 
K

K. W. Hours

Member
Thank you TallGirl.... have printed out all 9 pages (that I appreciate you having taken your time for me to preview, btw) and will read through this evening.
 
tallgirl

tallgirl

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Glendale, WI
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Controls Systems firmware engineer
K. W. Hours said:
Thank you TallGirl.... have printed out all 9 pages (that I appreciate you having taken your time for me to preview, btw) and will read through this evening.
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No problem! This is how I secretly have so much knowledge on all manner of bizarre and trivial topics -- I read Wikipedia to put myself to sleep at night :)

And seeing as it sounds like you're a student of some sort, best wishes on your studies, training, or generally getting to learn how to annoy electrons.
 
charlie b

charlie b

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K. W. Hours said:
Note to readers: This is a duplicate post that I, also, put out on the "Low Voltage and Limited Energy' Sub-forum (I am advising of this so as to not risk being an annoyance to anyone).
Click to expand...
Just FYI: We don't want the same question being discussed in two or more different places. It just gets too confusing, trying to remember what you said in reaction to what other comment in which of the duplicate threads. So the Moderators will close or otherwise remove all of the duplicates. That is what happened to your posted thread in the LV forum.
 
K

K. W. Hours

Member
charlie b said:

Just FYI: We don't want the same question being discussed in two or more different places. It just gets too confusing, trying to remember what you said in reaction to what other comment in which of the duplicate threads. So the Moderators will close or otherwise remove all of the duplicates. That is what happened to your posted thread in the LV forum.
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Yep. :- ) Thank you Charles for confirming.... this is what I guessed occurred .... and you can see that from the start I was concerned about the same as you.... with my newness to the board, not to mention the very subject of electricity, I was unsteady about where to post such a question.

Response from TallGirl on this SubForum got me out of the woods.

- Later.
 
tallgirl

tallgirl

Senior Member
Location
Glendale, WI
Occupation
Controls Systems firmware engineer
K. W. Hours said:
Yep. :- ) Thank you Charles for confirming.... this is what I guessed occurred .... and you can see that from the start I was concerned about the same as you.... with my newness to the board, not to mention the very subject of electricity, I was unsteady about where to post such a question.

Response from TallGirl on this SubForum got me out of the woods.

- Later.
Click to expand...

Well, I knew you were going to be getting a talkin' to. And besides, transmission lines aren't exactly "Low Voltage" or "Limited Energy" ;)

And would everyone just call me Julie? If I knew I was going to be called by my user name I'd have picked something else!
 
George Stolz

George Stolz

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Yeah, that's a courtesy awkwardly extended to people with "handles". If they signed on with a handle, then they were probably wanting to be unknown.

Just because someone tells you their name in a PM does not mean they'd like to share it with the world.

-Stan
 
H

hardworkingstiff

Senior Member
Location
Wilmington, NC
tallgirl said:
If the current (amperes) is halved, so too is the voltage drop. Since power is volts times amperes (more or less -- let's don't confuse the guy just yet :) ), halving the amps and doubling the volts allows the same total amount of power to be transmitted. Doubling the voltage in this manner means the voltage drop will be halved.
Click to expand...

Since the voltage is doubled and the voltage drop is halved, the voltage drop as a % of the voltage is dropped by a factor of 4.
 
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