A Sub-Cycle Approach to Dynamic Phasors With Application to Dynamic Power Quality Metrics

This paper addresses signal processing aspects of dynamic power quality monitoring in ac energy systems. The widespread use of high-bandwidth sensors enables a characterization of both steady-state and transient operation. However, the volume of so generated data is such that it necessitates extensive preprocessing and extraction of events of interest in estimation and control. We review approaches based on single (vector) samples, and compare them with methods that require full-period information, such as standard dynamic phasors. In this paper, we propose a sparse alternative to the standard (fast Fourier transform based) evaluation of dynamic phasors, thus bridging the gap between the two classes of techniques. We also outline the computational cost tradeoffs among different variants of sparse Fourier transform customized for electric energy system data.