Angle Reference Based Three-Phase State Estimation of Power Distribution Systems

Power distribution systems require three-phase state estimation due to their inherently unbalanced nature. Identifying a balanced reference bus is essential for conducting three-phase state estimation. However, such a reference bus is rarely available in distribution systems. Existing distribution system state estimation (DSSE) methodologies often randomly select a bus for this purpose, leading to biased results, while those based on a single angular reference face convergence issues. To address these challenges, this article introduces a novel method designed to mitigate the limitations associated with the reference bus in DSSE. This method is executed in two stages: first, it obtains the exact phase angles of the reference bus using local measurements available at that bus; second, it utilizes these precise phase angles to estimate the states of the distribution system. The efficacy of the proposed method is demonstrated through validation on the IEEE 13-node feeder, IEEE 37-node feeder, and IEEE 123-node feeder.