Novel approach to measurement of power system frequency using adaptive notch filter

A new approach for power system frequency estimating is proposed. The approach consists of two stages adaptive notch filter. The first stage eliminates harmonics and enhances the fundamental waveform. The subsequent notch filter is fed with down sampled version of enhanced signal obtained from previous stage. Down sampling expands the spectrum of signal, thus making it easier to detect. The adaptive coefficients of notch filter are obtained by a non-gradient algorithm. The proposed algorithm is efficient and its adaptive adjustment process is simple for real time implementation. Moreover, some simulations demonstrate the effectiveness of the algorithm in the presence of harmonics and noise.