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Homework Help: AC Circuit analysis

  1. Aug 31, 2013 #1
    1. The problem statement, all variables and given/known data
    Two nodes in a network are connected by a line with an impedance of 0.5 + 1.2j Ω. The voltage at the sending end is 33KV and at the receiving end is 32.5 KV with a lag of 1.5° compared to the sending end..

    Calculate the current in the line and the real and reactive power consumed by the line itself.

    2. Relevant equations
    Standard AC circuit analysis equations.

    3. The attempt at a solution

    I think I've got this just want to make sure that I'm not doing anything silly with the angles etc:

    ISR = VS - VR / 0.5 + j1.2 = (33) - (32.5 ∠ -1.5°) / 0.5 + j1.2

    = 763.45 ∠ -8.38°

    Real Power consumed = I2*Re(Z) = (763.45)^2 * 1/2 = 291.5 KW
    Reactive = I2Im(Z) = (763.45)^2 * 1.2 = 700KVAr

    Have I done anything silly? I feel to ask because it seems unusual to me that the reactive power is larger than the real power consumed by the line.

    Many thanks !
  2. jcsd
  3. Aug 31, 2013 #2


    User Avatar

    Staff: Mentor

    Looks okay.
  4. Sep 1, 2013 #3
    Great, thanks a lot !
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