THREE-PHASE APPARENT POWER CONVERTER AND THREE-PHASE POWER FACTOR CONVERTER USING TWO-WATTMETER METHOD

摘要

PURPOSE: To let converters take over the calculation of three-phase apparent power and three-phase power factor performed by a transformation CPU system. ;CONSTITUTION: Measuring parts 2, 3 are used to measure first and second power P₁, P₂ of a two-power method from line voltage V and line current I, the measured values P₁, P₂ are used to calculate three-phase active power P and reactive power Q by an active power calculation part 5 and a reactive power calculation part 6, and the measured values P, Q are used to calculate apparent power and power factor cosθ by an apparent power calculation part 8 and a power factor calculation part 10 for outputting. Since a converter 1c includes the active power calculation part 5 and the reactive power calculation part 6, it can also output three-phase active power P and three-phase reactive power Q. Since the three-phase apparent power and three-phase power factor can be output by the converter, calculation of the three-phase apparent power and power factor is not necessary in a transformation CPU system, thereby reducing a load of the transformation CPU system.;COPYRIGHT: (C)1995,JPO