ABSTRACT
Power systems operate at voltages for which kilovolt (kV) is the most
convenient unit for expressing voltage. Also, these systems transmit
large amounts of power, so that kilovolt-ampere (kVA) and megavolt-
ampere (MVA) are used to express the total (general or apparent) three-
phase power. These quantities, together with kilowatts, kilovars, amperes,
ohms, flux, and so on, are usually expressed as a per unit or percent of a
reference or base value. The per unit and percent nomenclatures are widely
used because they simplify specification and computations, especially when
different voltage levels and equipment sizes are involved.
