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Three winding transformer

  1. May 10, 2015 #1
    while studying the purpose of tertiary winding in the this 3-winding transformer , I'hv gone through a statement that " the zero sequence component caused by line-to-neutral load on secondary side cannot be balanced by primary currents as the zero sequence currents cannot flow in isolated neutral star connected primary".
    Now first of all I wanted to know that the currents in secondary are balanced by primary as this is the basic thing I am not getting this and why can't primary currents balance the zero sequence component ??
    And secondly why can't the zero sequence current flow in star-primary??
    I am missing some basics , so please elaborate it..??
     
  2. jcsd
  3. May 15, 2015 #2
    Thanks for the post! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
     
  4. May 15, 2015 #3

    jim hardy

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    Isolated neutral...... hmmmmm,,, you already know the answer...

    What is phase relation between zero sequence currents?

    What does KCL tell you about currents into that neutral node?
     
  5. May 19, 2015 #4
    the zero sequence are all in same phase with each other & there's a zero phase displacement between them .. I am not getting why the primary currents can't balance the zero sequence current??
     
  6. May 19, 2015 #5

    jim hardy

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    hmmmmm. all in phase? Do they all flow into or out of the the neutral in phase?

    seems there's no way back out of neutral? You said it's not connected ... Kirchhoff says what goes in must come back out?
     
    Last edited: May 24, 2015
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