Multistage strategies to incorporate phasor measurements into power system state estimation

This paper presents two novel estimation architectures to combine SCADA and PMU measurements into multistage strategies for Power System State Estimation. The first architecture makes use of a priori state information concepts and a blocked version of orthogonal Givens rotations with the objective of enhancing SCADA based estimates through PMU data processing. The second strategy is a three-stage scheme that relies on estimation fusion principles to optimally combine previously determined SCADA- and PMU-based estimates. In either case, observability with respect to PMU measurements is not assumed. multistage methods are described in detail and their computational requirements and properties are discussed. Results obtained for two IEEE test systems are used to illustrate the application of the estimation strategies.