Use of mixed radix FFT in electric power system studies

Radix-2 based fast Fourier transform (FFT) routines have been the main stream FFT that are commonly applied to the measurement and analysis of electric power system data. Because of the rigid sampling rates offered by most of the instrument manufacturers and the mathematical limitation imposed by the algorithm of radix-2 FFT, artificial post sampling data windows have been introduced to improve the utility of the radix-2 FFT. The 60 Hz and the 50 Hz based electrical power system frequencies are incompatible with the radix-2 FFT. There has been an ongoing search to adapt the FFT routine to the special requirements of electric power systems. Advances in the personal computer hardware has opened a new approach to perform the FFT via mixed radix routines. It offers greatly improved flexibility in the selection of a practical data size. This leads to the elimination of the need of the post sampling software windows. It also allows one to relax or eliminate the requirement of anti-aliasing measures for power system harmonic measurements