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Load angle of generator

  1. Apr 6, 2013 #1
    Is there a mathematical equation for calculating the load angle of a generator?
    I'm trying to calculate the real and reactive power of the generator which the equation I am using is
    EV/Xd sin delta
    where E is the generator excitation voltage
    V is the generator terminal voltage
    Xd is the generator reactance
    and delta is the load angle of the of voltage E and V
    Thanks in advance the the help
  2. jcsd
  3. Apr 8, 2013 #2


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    Gold Member

    Load angle is between stator and rotor fields (vectors). It is a function of power and excitation current, in general.
    You can be calculate it from detailed mathematical model of machine (which is rather.. complicated). Otherwise, it can be estimated. See eq 1 and 2 in this paper:


    Now, it all depends how accurate this calculation needs to be. You can assume that Xq~Xd (quite accurate, use only for cylindrical generator).
    If you want to know it's exact value.. Xq is not among standart parameters (provided by manufacturer, from my experience). You need a series of measurements to estimate it (or good knowledge + all design data to calculate it).

    Ok, this was answer to your question. May I ask now what is the purpose of this calculation ? I suggest using other set of parameters to calculate power (forget about load angle). Why not using vectors -> stator current, stator voltage and power factor ?
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