Instantaneous phase tracking in power networks by demodulation

In the paper we present results of our study of a technique for instantaneous monitoring of phase angles during transients in power networks. 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 degree). We specifically examine the effects of the low-pass filter on the estimation error. Various FIR and IIR filters were tested on simulated scenarios of transient conditions in power networks. The simplicity of the method and the shown remarkable performance make it an excellent candidate for real-time implementation.