Accurate Measurement of Reactive Power Based on Fryze's Definition of Time Domain Reactive Power

In view of the lack of accuracy of reactive power measurement in reactive power measurement under nonsinusoidal unbalanced conditions, this paper proposes a nonsinusoidal unbalanced three-phase method based on the definition of Fryze's time domain reactive power. Three-wire system reactive power measurement theory. According to the definition of Fryze time domain reactive power, three-phase instantaneous current is decomposed into active current component and reactive current component, and three-phase instantaneous voltage and reactive current component are subjected to fast Fourier transform to obtain various harmonic reactive power. Size and direction to achieve accurate metering of reactive energy for non-sinusoidal unbalanced three-phase three-wire systems. This method divides the reactive power into positive reactive power and reverse reactive power, avoiding the situation where the harmonic reactive power and capacitive reactive power generated by the same harmonic source cancel each other out. Finally, this conclusion is verified by Matlab simulation, which provides a theoretical basis for accurate measurement of system reactive power under nonsinusoidal unbalanced conditions.