Phase measurement of distorted periodic signals based on nonsynchronous digital filtering

Measurement of the phase angle between fundamental components of distorted periodic signals at power frequencies is described in the paper. It is based on a nonsynchronous multirate digital filtering algorithm, which is applied at the voltage and/or current signals to be measured. The digital filters implemented are designed to suppress the higher harmonics and ensure the accuracy of measurement. The measurement method is insensitive to frequency variations in a wide frequency band around the nominal frequency. A verification of the method has been performed by simulations and by measurements. The results of extensive performance evaluation are reported