On the definition of power factor and apparent power in unbalanced polyphase circuits with sinusoidal voltage and currents

Definition for the apparent power S and for the power factor PF in unbalanced polyphase circuits with sinusoidal waveforms are presented. It is proved that the definition S/sup 2/=(V/sub a//sup 2/+V/sub b//sup 2/+V/sub c//sup 2/) (I/sub a//sup 2/+I/sub b//sup 2/+I/sub c//sup 2/) has a definite physical meaning, leading itself to a convenient resolution in positive, negative and zero sequence, nonactive and active power. It is suggested that the power factor be represented with the help of the ratio P/sup +//S, where P/sup +/ is the positive sequence active powers.<>