Reconstruction of phasor dynamics at higher sampling rates using synchrophasors reported at sub-Nyquist rate

The IEEE standard C37.118.1-2011 specifies performance requirements for the synchrophasor measurements. In this standard, the maximum modulation frequency for the phasor domain oscillations is 5 Hz. The synchrophasor reporting rates below 10 frames/s are exempted from the dynamic requirements of the standard. Synchrophasors reported below 10 frames/s cannot be used in the dynamics monitoring applications due to violation of the Nyquist theory (considering maximum 5 Hz oscillation frequency). Recently, compressive sampling (CS) theory has generated significant interest in the signal processing community because of its potential to enable signal reconstruction from fewer samples than suggested by the Nyquist rate. In this paper, the CS theory has been used to reconstruct the signal dynamics at higher rates using synchrophasors reported at the sub-Nyquist rate. This cannot be achieved in the conventional interpolation theory due to aliasing. As an example, in this paper, synchrophasors of an amplitude and frequency modulated (5 Hz) waveform are reported at 8 frames/s; thus causing aliasing. This aliased data is used in the phasor data concentrators (PDCs) to accurately (low TVE) reconstruct the synchrophasors at 24 frames/s rate using CS theory. The results indicate that the CS theory may also be useful in reducing the communication bandwidth requirements.