Comparative Study of Various Methods of DFT Calculation in the Wake of IEC Standard 61000-4-7

This paper discusses various methods of calculating coefficients in Fourier series. In particular, the methods recommended in IEC Standard 61000-4-7 and the methods applied in commercial power quality analyzers were investigated. The analysis was carried out for a simulated signal and based on the real voltage registered in an isolated electric power system. It consists of uncertainty evaluation and computational complexity assessment. In the latter case, a digital signal processor simulator and software developed by the author were used. Finally, suggestions for constructors of future power quality analyzers were formulated.