Reactive power and power factor

GENERAL definitions exist for potential, current, and active and reactive power, that are independent of wave form and of circuit conditions. In order to use these quantities in circuit analysis when there are harmonics present, it is necessary to know their individual harmonic components. By definition, singlephase power factor is a blanket factor which covers and so disregards any deviation in wave form from the sinusoidal. Thus it is not a quantity that can be used in circuit analysis when there are harmonics present. If polyphase power factor is defined as the ratio of the power to the magnitude of the vector volt-amperes it is likewise a useless quantity in circuit analysis if there are harmonics present. Furthermore, this definition of polyphase power factor makes it a derived quantity which depends upon the active and reactive power. Even when there are no harmonics present so that power factor may be legitimately used, the circuit calculations are usually simpler if the loads are determined by their active and reactive powers rather than by their power factors. That is, as far as circuit analysis is concerned, power factor is a quantity whose retirement need scarcely be noted.