Real-Time Power System Frequency and Phasors Estimation Using Recursive Wavelet Transform

Phasor frequency, magnitude, and angle describing a sinusoidal signal are widely used as critical variables in algorithms and performance indices in many power system applications, such as the protection relaying and state monitoring. This paper proposes a novel approach for estimating the phasor parameters, namely frequency, magnitude, and angle in real time based on a newly constructed recursive wavelet transform. This algorithm is capable of estimating the phasor parameters in a quarter cycle of an input signal. It features fast response and achieves high accuracy over a wide range of frequency deviations. The signal sampling rate and data window size can be selected to meet desirable applications requirements, such as fast response, high accuracy, and low computational burden. Besides, an approach for eliminating a decaying dc component, which has a significant impact on estimating phasors, is proposed by using a recursive wavelet transform. Simulation results demonstrate that the proposed methods achieve good performance.