Tuning of Measurement Weights in State Estimation: Theoretical Analysis and Case Study

Based on well-known statistical laws characterizing the propagation of errors, and the guidelines provided by the related international standards, this paper first presents a theoretical analysis of the uncertainty associated with the conventional measurements used by weighted least squares state estimators. Three major sources of errors are considered, namely instrument transformers, measuring devices, and deadband errors, leading to algebraic expressions that clearly show the contribution of each major factor to the overall uncertainty. Then, the methodology is applied to the subtransmission systems of Unión Fenosa Distribución, and a comparison is performed illustrating the potential benefits arising from the use of the proposed weighting coefficients.