Effect of Phasor Measurements on the Choice of Reference Bus for State Estimation

This paper revisits the state estimation problem formulation by assuming availability of at least one phasor measurement unit (PMU) in the system. Existence of PMU measurements eliminates the need to choose a reference bus in the formulation of the state estimation problem. However, it also necessitates a mechanism by which erroneous PMU measurements can be detected, identified and removed from the measurement system. The paper investigates the requirements to ensure robust state estimation in the presence of single PMU errors. These requirements are verified by implementing a GPS referenced state estimator using test systems containing one or more PMU measurements.