Real-time phasor measurement method including a GPS common time-stamp for distributed power system monitoring and control

The supply of high quality electrical energy in power systems requires access to a synchronized phasor that is measured at various locations via a phase measurement unit (PMU). These data are then tagged with timestamps, provided by a Global Positioning System (GPS), and then sent to a control unit. The existing methods place demanding constraints on the computing resources; hence, a new method of extracting synchronized phasors is proposed to address this issue. The new method combines a multirate phase locked loop (MPLL), a real-time positive sequence detector, and a GPS common time-stamp unit. The MPLL is based on a PLL architecture that incorporates frequency adaptation intrinsically. The MPLL constitutes a multirate sample rate system that relaxes the implementation of a front-end analog anti-aliasing filter. Furthermore, a digital bandpass filter is included to enhance the performance of the MPLL under severe line disturbance conditions. An automatic gain control (AGC) prevents any variations of amplitude in the input signals from affecting the PMU.