Transient behavior of the full-cycle DFT Phasor Estimator

The paper analyzes the transient behavior of the phasor estimator provided by the full-cycle Discrete Fourier Transform (DFT) of a power system signal. To this aim the theoretical expression of the DFT Phasor Estimator (DFT-PE) is derived in the case when the observation interval contains both an abrupt variation in the fundamental component amplitude and/or phase, and a decaying dc-offset. The obtained results allow the determination of the DFT-PE phasor amplitude and phase errors during the whole estimation transient. The accuracies of the provided expressions are extensively verified by means of computer simulations.