Use of recursive wavelet transform for estimating power system frequency and phasors

Frequency, amplitude and phase angle are three major parameters describing a stationary sinusoidal signal. In power system, many applications such as the state monitoring and protective relaying measure these parameters as performance indices or critical variables in the algorithm criteria respectively. This paper proposes a new method for estimating the power system frequency and phasors in real time based on a recursive wavelet transform. The frequency estimation algorithm is capable of accurately estimating the frequency within three samples of an input signal. It features fast response and achieves accurate frequency estimation over a wide range of frequency changes. For estimating phasors, the signal sampling rate and data window length can be selected to meet desirable applications requirements such as high accuracy and low computational burden. Simulation results demonstrate that the proposed method achieves good performance.