Statistical Criteria for Evaluation of Distribution System State Estimators

The increasing penetration of distributed energy resources and electric vehicles, along with the strict requirements for power quality and system reliability have changed the way distribution systems are planned and operate. Therefore, it is of great importance for the Distribution Management System (DMS) to have functions adequately designed to analyze distribution systems. As the state estimator acts like a filter for the real-time measurements, it will constitute the core of the DMS. In this context, this paper presents a set of statistical criteria, namely bias, consistency and quality, that can be used to properly evaluate distribution system state estimators. The application of these criteria is illustrated considering four well-known distribution system state estimators on the IEEE 34bus distribution feeder. Additionally, the performance of these estimators in terms of accuracy and computational efficiency is analyzed and discussed. The purpose of the paper is to highlight the importance of considering more strict criteria for assessing distribution system state estimators, rather than just number of iterations, execution times and the difference between estimated and true states.