Enhanced FFT-based parametric algorithm for simultaneous multiple harmonics analysis

An enhanced FFT-based parametric (E-FFT) algorithm suitable for on-line har monic analysis of electrical power systems is presented. This E-FFT algorit hm exploits its iteration loops in combination with the characteristic of s teep-descent gradient search strategy, to limit the sensitiveness of the to tal harmonic distortion caused by changes in the number of parameters invol ved in distorted signal models. The E-FFT algorithm performs reasonably wel l with short data record length. Unlike most gradient-descent search algori thms for a global minimum point, the proposed E-FFT algorithm averts the ri sk of being trapped at any local minimum point in the search path. The E-FF T algorithm differs from other FFT and Kalman filter based tracking algorit hms, in that it is able to provide simultaneous tracking of co-variations b etween integer and non-integer (sub) harmonics in a small number of iterati on steps. Numerical illustrative examples demonstrating the operation of th is E-FFT algorithm and its simulated performance results are also presented .