per unit conversion

Discussion in 'General Electronics Chat' started by almotions, Nov 4, 2009.

  1. almotions

    Thread Starter Active Member

    Feb 6, 2009
    46
    0
    Hi all,
    assuming a three-phase supply (25k Vrms phase-phase) supplying a three-phase load. I connected a voltage and current measurement block having a base voltage of (25k Vrms phase-phase) and base power of
    (1M VA 3 phase). With the pu voltage and current measurements into a active and reactive power measurement block,the output of the power measurement block must be multiplied by a gain of 2/3 in order to have the correct active and reactive power measurement.My question is why 2/3?
    All these are simulated in SIMULINK/MATLAB.Thanks..


    Regards,
    alvin
     
  2. mik3

    Senior Member

    Feb 4, 2008
    4,846
    63
    I think is the ratio of the base value to the maximum value.
     
  3. lmartinez

    Active Member

    Mar 8, 2009
    224
    6
    Provide a oneline diagram of the power system being analyzed? It will visually help us provide more detail assistance to your question.........
     
  4. Duane P Wetick

    Active Member

    Apr 23, 2009
    408
    19
    If each phase feeds 2 loads, and the loads are then split between the other two phases, then the system is considered balanced. (assuming the load VA's are the same.) You don't have to worry about the vectored relationships if all are equal, just simple math will suffice.

    Cheers, DPW
     
    Last edited: Nov 8, 2009
  5. almotions

    Thread Starter Active Member

    Feb 6, 2009
    46
    0
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