New concept in AC power theory

Conventional power theory is examined in the time and frequency domains, and a new definition of apparent power in single- and three-phase systems is presented. The technique is based on the instantaneous power, which satisfies the law of conservation of energy. In this technique reactive power is determined as a DC imaginary component of the instantaneous power. Apparent power is defined as the RMS or 2-Norm of instantaneous power. The technique satisfies the Plancherel´s theorem both in time and frequency domain. It is shown that power factor can only be made to be unity in a three-phase balanced system if the new definition of apparent power is used