Need Help in "Harmonics in polyphase power system"

Discussion in 'Homework Help' started by mnada, Apr 28, 2012.

  1. mnada

    Thread Starter New Member

    Apr 5, 2012
    Dear All,
    I have a problem in understanding how the harmonic currents exist in a load with no corresponding harmonic voltages?
    The following figures with questions under explain what I mean

    This understood figure no issues about.


    In above figure, 2 question arise::confused:

    • How the line currents are missing the triplen harmonics
    • How the phase voltage is missing the other odd harmonics except the triplen


    In the above figure::eek:

    • How is the phase voltage missing all the harmonics while it's present in current.
    • Correct me if I am wrong: we can say that because triplen harmonics are in phase they cancel each other in the line cuerrent
    Thank you
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    Attached is my attempt at an explanation which unfortunately is rather wordy.
    mnada likes this.
  3. mnada

    Thread Starter New Member

    Apr 5, 2012
    I really appreciate your time and effort. Your response is quite helpful
    I fully agree with you that the second figure is missing the fundamental frequency voltage across the star connected load, that make perfect sense.