8. Phasor-Aided State Estimation

This chapter explores the idea that synchrophasors contribute to increasing data redundancy for SE, making their incorporation into existing SCADA-based estimators indisputable. SCADA (supervisory control and data acquisition) measurements are complemented by synchrophasors, i.e., bus voltages (magnitudes and phase angles) and branch currents (real and imaginary parts), available employing PMUs, sited at designated buses in the network. Two schemes are presented: (a) combine conventional with phasor measurements and process them by adopting a single (hybrid) estimator, and (b) take conventional and phasor measurements as individual sets and process them separately using two estimators. A data validation/diagnosis scheme is based on a residual analysis, such as the innovation analysis performed in forecasting-aided state estimators. An illustrative example showing the processing of spurious SCADA measurements is presented. Advanced topics, proposed problems, and references are at the end of the chapter.