Reflections on Apparent Power and Power Factor in Nonsinusoidal and Polyphase Situations

In this paper it is shown that it is not possible to generalize the classical concepts of apparent power and power factor to the general polyphase nonsinusoidal case by unique concepts if one wants to retain the meaning with respect to efficiency of the electrical energy transfer as well as with respect to power oscillations. Separate generalizations are proposed and discussed. The concept of apparent power has for many years been a strongly debated topic in electrical engineering. Its definition is intensely discussed in connection with the new IEEE Standard. The classical definitions for the single-phase sinusoidal or balanced three-phase situations served the industry well, but the increasing causes of distortion and unbalance in power systems necessitate a new set of definitions of power quantities relevant for these situations. This paper critically reviews existing definitions, highlighting the need for distinct characterization of efficiency and oscillatory behavior in power transfer.