A real-time phasor data only state estimator and its application to real power systems

Abstract

Previous work, completed by Dr. Luigi Vanfretti, developed a phasor-only state estimator which used correction factors to account for the inherent inaccuracies found in measurements added from the equipment in the field. This proposed phasor state estimator not only estimates the voltage magnitudes and angles, but also variables that account for measurement error such as angle biases and current scaling factors. Dr. Scott Ghiocel then applied this state estimator to a small subset of the Central New York system in order to study the use of the PSE to a larger system. In this thesis we will study the application of the phasor-only state estimator to a wide-scale power system, enumerate the changes required to adapt the phasor-only state estimator to handle a real system and describe the steps taken to advance the phasor-only state estimator to a near real time application.

With the growing concern about reliability in the electrical system, it is important for those monitoring the grid to receive a clear and holistic snap shot of the high voltage portions of the grid in real time. It is possible to achieve real time situational awareness using phasor data. There are several issues that must be addressed when using phasor data. PMU measurements have opportunities for inaccuracies which are usually introduced by human error. Another issue is that unlike the current standard measurements, Phasor Measurement Units do not cover the entire electrical system. Using a phasor-only state estimator, it is possible to both enhance data quality by removing angle error and expand the observable area of the grid.