New high precision harmonic analysis method for power quality assessment

The power quality is one of actual major problems in electrical engineering. Generally, power electronics equipments damage power quality parameters, disturbing radio communications or the functionality of other equipments. A rigorous design of most appropriate filters for power quality improvement is possible only through a high precision analysis that allows estimating power quality parameters and the influence of each harmonic component on the network-drive system. Actual industrial equipments intended to perform spectral analysis are not appropriate for strongly deformed signals, with frequent discontinuities, as in power electronics. Our paper presents a new and accurate method of harmonic analysis that permits to mitigate most of power quality related problems. The principle is to estimate intermediate points between the initial samples given by the available data acquisition system; therefore, the Fourier coefficients are estimated more precisely using the fast Fourier transform. As interpolation technique we chose the reconstruction of the analog signal using an ideal lowpass filter. The excellent results are validated on a pair of synthesized signals having known harmonic spectrum