Abstract: In this paper, a close accord on the Discrete Fourier Transform (DFD
technique based frequency and phasor estimations for protective numerical relays
application is presented The eflectiveness of the recursive DFT, in particular, is
examined via simulation corroborated by experimental verification. Possibility of
error accumulation in the estimated magnitude by the recursive DFT is highlighted
and novel solutions are proposed. Impuct of different input signal patterns on the
algorithms' performance is further examined. In addition, effect of rate of change of
input signal friquency on the estimated values is pinpointed. The testing circuit
hardware is implemented using the digital signal processing technologv. The results
of this studv are great& valuable for the protection engineers particularly those
cuncerned with the development and implementation of numerical rela-vs