Discrete-Fourier-transform-based technique for removal of decaying DC offset from phasor estimates

A technique to suppress the negative effect of a decaying DC offset on phasor estimates using a digital Fourier transform algorithm is presented. The proposed technique is based on evaluation of the decaying DC component in the signal. The technique is suitable for all prevailing systems and fault conditions. The performance of the technique is evaluated in both the time and frequency domains. Simulation results showing the effectiveness of this new technique are presented. The proposed technique is further evaluated when it is used in a distance relay design.