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Homework Help: Power Loss Due to Resistance

  1. Apr 13, 2009 #1
    1. The problem statement, all variables and given/known data

    A high-voltage transmission line with a resistance of 0.345 ohms /km carries a current of 1.05 kA. The line is at a potential of 600 kV at the power station and carries the current to a city located 173 km from the power station.
    A>What is the power loss due to resistance in the line?
    B>What fraction of the transmitted power does this loss represent?

    2. Relevant equations


    3. The attempt at a solution

    part A>I used the kilometers to figure out the resistance from the distance. I then tried pluging in the values into the equations but the answer is not working.

    partB> In order to calculate the fraction I want to make sure I am setting hte first part of the equation correctly. But I assume that you subtract the power loss from the original power.
  2. jcsd
  3. Apr 13, 2009 #2
    your second equation is wrong, its P=(V^2)/R
    maybe that might help?
    also could you tell me the answer to see if i got it right =]
  4. Apr 13, 2009 #3
    OK I keep getting it wrong

    so I now tried: P=I^2*R

    I did 0.345ohms/km * 173 km= 59.685

    Then I did P=I^2*R to get> (1.05kA*1.05kA)*(59.685ohms)= 65.8 kW

    BUT it keeps telling me I am WRONG!!! PLease help!!
  5. Apr 13, 2009 #4
    You might wanna plug that into your calculator again :P

    (1,05 * 10³)² * 0.345 * 173 = 65.8 MW

    Is that the correct answer? (sounds like a little too much to me but I don't know...)
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