The transient response of the digital filter for relaying purposes has been improved by means of the Taylor–Kalman–Fourier (TKF) filter. This filter is focused on a dynamic phasor, which is adapted to the transient operating conditions and is based on a signal model that is approximated by the Kth Taylor polynomial. This model is extended to the Kalman and Fourier subspaces in order to provide instantaneous estimates through its recursive property. The TKF renders instantaneous phasor estimates at each sample and enhances the impedance estimation under fault conditions. This fact and the results demonstrate the applicability of the proposition for distance relays.