Stationary wavelet transform and single differentiator based decaying DC-offset filtering in post fault measurements

Half‐cycle method for exponentially DC components elimination applicable in phasor estimation

“…In the last two decades, wavelet transform and also neural network have been utilised for fault detection and phasor estimation application in power systems [17][18][19][20][21][22]. According to [20], from practical point of view, the assumed signal in [17] is not suitable in power systems since the assumption of total removal of exponentially DC component utilising a band pass anti-aliasing filter in [19] or high pass fourth-order Butterworth filter in [18] result unnecessary delays, without any remarkable improvement in performance rationalisation.…”

An analytical approach for removal of decaying DC component considering frequency deviation

“…Several methods based on wavelet transform have been proposed for filtering application and phasor estimation during fault conditions in transmission line [27][28][29][30][31][32][33]. However, based on observation in [30], the signal utilized in [27] is not practical in power system, and that the hypotheses of complete elimination of decaying DC offset by a band pass anti aliasing filter in [29] or High pass 4th order Butterworth filter in [28] caused inessential delays, without any considerable performance rationalization.…”

Real‐time fault analysis of transmission lines using wavelet multi‐resolution analysis based frequency‐domain approach

“…Some efficient frequency‐domain approaches based on wavelet transform (WT) evolved to overcome the above mentioned limitations. WT has good resolution in both time and frequency domain compared with Fourier transform (FT) [4, 5] and short‐time FT [6–10]. The actual implementation of WT is done through multi‐resolution analysis (MRA).…”