Using pseudo and virtual measurements in distribution system state estimation

This paper reports a study on the use of pseudo-measurements and virtual measurements in the process of state estimation in distribution systems. For this purpose, a three-phase weighted least squares state estimator was developed, which treats SCADA measurements, virtual measurements and pseudo-measurements similarly, assigning different weights for each of these measurements. Initially, this research will examine the effect of pseudo-measurement precision on the estimates. Then, it will demonstrate that the substitution of pseudo-measurements by virtual measurements, at strategic points, improves the estimation accuracy. To illustrate the main theoretical conclusions, results of case studies considering a 4-bus test system, featuring the characteristics present in an electrical power distribution system (radial and not symmetrical network, and unbalanced loads), will be presented and analyzed.