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What is the power loss due to resistance in the line?

  1. Feb 5, 2007 #1
    1. The problem statement, all variables and given/known data

    A high-voltage transmission line with a resistance of 0.30ohm/km carries a current of 1050 A. The line is at a potential of 670 kV at the power station and carries the current to a city located 164 km from the station.

    (a) What is the power loss due to resistance in the line? W

    (b) What fraction of the transmitted power does this loss represent? %

    2. Relevant equations

    W = AdeltaV


    3. The attempt at a solution

    first i did 1050A/1000 to convert that into 1.05 kA (not sure if this is correct)

    then i did 1.05 x 670 = 703.5 kW or 703500 W (still not sure if im doing this correctly)

    that is when i get lost on how to do the next step, but from what i been doing i think i am doing it wrong and it will only lead me to confuse myself even more.

    thanks for any help.
     
  2. jcsd
  3. Feb 5, 2007 #2

    Integral

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    What is the resistance of the power line?

    Given that and voltage or current power loss is easy.
     
  4. Feb 5, 2007 #3
    the resistance of the power line is .30 ohm/km and the current is 1050 A
     
  5. Feb 5, 2007 #4

    Integral

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    You need the total resistance.
     
  6. Feb 5, 2007 #5
    .30 ohm/km x 164 km = 49.2 ohm km (total resistance)
     
  7. Feb 5, 2007 #6

    Integral

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    Think a bit about the units you have writen on the above number.

    Now that you have the resistance you should be able to complete the proplem.
     
  8. Feb 6, 2007 #7
    Okay, i been trying to figure this out and still lost on how I would go about finding the power loss due to the resistance.

    I know that to get the total power its A x DeltaV = total W

    so i did 1050A x 670000 = 703500000 W (which might be wrong) since i think 670 kV = 670000

    that is where i am unsure what to do next or what I need to do with the total resistance
     
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