Accurate frequency estimation in power systems by DSP

A method of integrating zero-crossing for accurate estimation of the actual power-line frequency is considered. It is based on integration of samples of power-line voltage and on interpolation of the integrated value near its zero-crossing. The main advantage of this method as compared to conventional zero-crossing technique is a significant increase in resolution and a decrease of round-off errors of A/D-converter. Due to its simplicity, rapidity and efficiency, this method can be used as a basis for prediction of the actual power-line frequency and for other DSP-applications. Theoretical and experimental data concerning proposed method are described and discussed.