Quasi-synchronous sampling algorithm and its applications-III. High accurate measurement of frequency, frequency deviation and phase angle difference in power systems

A robust computation technique for measuring the frequency, the frequency deviation and the phase angle difference between two periodic components of currents and/or voltages in power systems, based on quasi-synchronous sampling algorithm, is described. Using this method the influence of distortion of the measured signal and the asynchronization error can both be reduced considerably, which ensures a higher accuracy of the frequency and phase angle difference measurement even for multiple frequency signals