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Symmetrical Components

  1. May 14, 2013 #1
    I wonder if someone can help me how to find the symmetrical components of a 5-phase system. What would be the positive and negative sequences? I'm saying this because in a 3-phase system I can find the positive, negative and zero sequence in function of line currents.
     
  2. jcsd
  3. May 14, 2013 #2
    Have you tried your self?

    check out wikipedia

    Or the famous article by Fortescue

    As a push in the right direction, how many balanced systems (sequences) do you need?
     
  4. May 14, 2013 #3
    I have no reference on doing fortescue transformation for system with phases different from 3.
     
  5. May 14, 2013 #4
    In fact, I'm trying to perform this using simulink, but it does not have any block with phases different from three. So I don't know how to watch the qd0 -waveforms of a synchronous machine with 5-phase .
     
  6. May 31, 2013 #5
    See "Symmetrical Components" by Wagner & Evans, 1933, still in print.

    Claude
     
  7. Jun 7, 2013 #6
    With 3-phase there are 3 components, I1 (positive, A-B-C), I2 (negative, C-B-A), and I0 (zero, all 3 in unison), called "sequences".

    With 5-phase there are 5 components. They are I1 (positive, A-B-C-D-E), I2 (A-C-E-B-D). I3 (A-D-B-E-C), I4 (negative, E-D-C-B-A), and I0 (zero, all 5 in unison).

    In general for n phases there will be n sets of phasors. No. 1 is the positive sequence, having the same rotation as the overall system, i.e. A, B, C, etc. No. 2 is the next set where the sequence is every 2nd phase, i.e. A-C-E-G, etc. No. 3 is next, with sequence A-D-G, etc. which is every 3rd phase. The next to last set is no. "n-1" which is negative sequence, i.e. n, n-1, n-2, ---, C, B, A. Finally we have zero sequence, all n phases in unison.

    Claude
     
    Last edited: Jun 7, 2013
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