SUBSPACE-BASED APPROACH TO SYNCHROPHASOR ESTIMATION

A subspace-based approach to synchrophasor estimation is provided. Embodiments described herein provide two improvements to subspace-based phasor measurement unit (PMU) algorithms based on estimation of signal parameters via rotational invariance techniques (ESPRIT) frequency estimation. The first is a dynamic, real-time thresholding method to determine the size of the signal subspace. This allows for accurate ESPRIT-based frequency estimates of the nominal system frequency as well as the frequencies of any out-of-band interference or harmonic frequencies. Since other frequencies are included in the least squares (LS) estimate, the interference from frequencies other than nominal can be excluded. This results in a near flat estimation error over changes in a) nominal system frequency, b) harmonic distortion, and c) out-of-band interference. Second, the computational burden of ESPRIT is reduced and the proposed algorithm runs in real time on resource-constrained platforms.