Instantaneous phase tracking in power networks by demodulation

Results of a study of a technique for instantaneous monitoring of phase angles during transients in power networks are presented. The technique is based on demodulation and subsequent filtering of the measured signal. It allows very accurate tracking of transient phase angles (with estimation errors within 1 degrees ). The effects of the low-pass filter on the estimation error are examined. Various finite impulse resonse (FIR) and infinite impulse response (IIR) filters were tested on simulated scenarios of transient conditions in power networks. The simplicity of the method and its demonstrated performance make it an excellent candidate for real-time implementation.