Hi
Is my categorization of complex power S into phasor form, polar form, and rectangular form correct? Did I miss any category? Thank you for your help.
Hi
Is my categorization of complex power S into phasor form, polar form, and rectangular form correct? Did I miss any category? Thank you for your help.
The first and the second line formulae are correct.
The third line result has to be: P=Vrms^2*R/(R^2+X^2) and Q=Vrms^2*X/(R^2+X^2) since: (R-jX)*(R+jX)=R^2+X^2
He did not need to use the conjugate for S = v^2/Z
The difference between genius and stupidity is that genius has its limits.
[QUOTE=Ingenieur;1858884]He did not need to use the conjugate for S = v^2/Z[/QUOT
IEEE Std 1459-2010, IEEE Standard Definitions for the Measurement of Electric Power Quantities Under Sinusoidal, Nonsinusoidal, Balanced, or Unbalanced Conditions. 3.1.1.3 Reactive power (var)
“NOTE 1— If the load is inductive, then Q > 0. If the load is capacitive, then Q < 0. This means that when the current lags the voltage θ > 0 and vice versa.”
Using Z=R+jX instead of Z*=R-jX the resulted Q<0 [capacitive].Usually X is inductive.
[QUOTE=Julius Right;1858996]Yes he did!
Actually, the resulting Q^{2} is always positive, allowing Q to be either positive or negative.
If you do simple complex multiplication without the conjugate you get a negative value for
q^{2}, which is impossible, and you get cross terms which still contain j, also unphysical for power.
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