1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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

    P=IV
    p=V^2(R)


    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 =]
    cheers
     
  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...)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook