State Estimation Algorithms

This chapter briefly discusses some of the commonly used state estimation algorithms. Standard assumptions regarding the statistical distribution of the measurements are explained. Weighted least squares (WLS) is the most commonly used state estimation algorithm. The basic formulation of the WLS state estimator is discussed, along with the steps for its implementation. With the increasing deployment of phasor measurement units (PMUs) in power systems, there is a requirement of hybrid state estimators that can accommodate both conventional and PMU measurements. Possible ways of inclusion of PMU measurements in a state estimator are elaborated in this chapter. Formulation of a linear state estimator for PMU-only measurement system is discussed next. Dynamic state estimators (DSEs), which are having several advantages over conventional static estimators, are getting increasing attention from researchers. Basic formulations of the dynamic state estimation problem are also discussed in this chapter.