Truncation effects of FFT on estimation of dynamic harmonics in power system

This paper investigates the truncation effects of the fast Fourier transform (FFT) on harmonic estimation in the power system. Special efforts are concentrated on the voltage and the current with time-varying waveforms. The effects on the time response of the dynamic harmonic estimation are discussed. An overlap truncation method is proposed to achieve a faster response. A full-converter fed DC drive is used as an example to illustrate the implementation of the overlap truncation method and group-harmonic identification for dynamically evaluating the harmonic distortion of a power system.