Three-phase Definitions in IEEE Standard 1459

IEEE Standard 1459 has been under revision since 2019. The standard defines, for the purposes of measurement, four “power quantities.” They are power, reactive power, apparent power and power factor. The definitions are supposed to apply under sinusoidal and nonsinusoidal, balanced and unbalanced conditions. Inconsistencies encountered in measured results have challenged many investigators over more than a century. The present revision is based on aspects of measurement theory that were not known to earlier writers on the topic of the measurement of these quantities. This paper explores some aspects of the theory, and gives a short summary of anticipated changes in the standard.