FFT-Based Amplitude Estimation of Power Distribution Systems Signal Distorted by Harmonics and Noise

This paper estimates amplitude of a power distribution systems signal corrupted with white noise and harmonics by using the windowed symmetrical interpolation fast Fourier transform. The polynomial coefficients of amplitude estimation are derived. The influence of harmonic and the spectral interference (leakage) from image parts is analyzed. The analytical expression of the amplitude estimation variance is derived and compared with the unbiased Cramer-Rao lower bound. The proposed methods are validated through computer simulations and experiments.