An observability analysis method for a combined parameter and state estimation of a power system

This paper presents a new observability analysis method of a power system for a combined parameter and state estimation based on the weighted least-squares (WLS) state estimator. In this approach, the state vector is expanded to include both the V-/spl theta/ state variables and a given set of branch parameters. This augmented state vector is estimated by processing a large collection of measurements recorded over several snapshots of the power system during which the actual system state is quasi static, that is, varies over a small range. This situation typically occurs during the night off-peak periods. The performance of the proposed observability algorithm is evaluated on a small-scale test system.