Measuring of Inactive Powers in Three-Phase Power Supply System

Abstract

In the paper, a method for measuring the inactive powers of a three-phase power supply system based on operations with currents and voltages represented in the αβ - coordinate system is proposed. It is shown that measuring the four scalar powers and apparent power of a three-phase threewire system based on currents and voltages represented in the αβ-coordinate system requires four wattmeters, which is half as much as when using non-convertible values of currents and voltages. The six scalar powers of the three-phase four-wire power supply system can be determined based on the readings of six wattmeters. The experiment showed the adequacy of calculated and experimental data. Change in the nature of the load while preserving the value of the first load current harmonic does not affect the integral values of four scalar powers.