Fundamental Phasor Calculation With Short Delay

Fundamental phasors are used to monitor and control power systems. The conventional method of calculating the phasors is using a Fourier transform, which introduces a delay of at least one fundamental cycle. This paper examines the feasibility of exploiting an alternative using a direct-quadrature (DQ) transformation to calculate the phasors by extracting the fundamental component from a three-phase voltage or current in the DQ reference frame, which may be distorted by unbalanced components and harmonics. The proposed method allows obtaining a clean fundamental component of three-phase quantity with a minor delay less than one third of a fundamental cycle.