Decentralized Coordinated State Estimation in Integrated Transmission and Distribution Systems

TL;DR

This paper introduces a decentralized coordinated state estimation method for integrated transmission and distribution systems, enabling accurate, global monitoring while addressing boundary mismatches and improving over independent estimation approaches.

Contribution

The paper presents a novel decentralized method for integrated system state estimation that improves accuracy and consistency across transmission and distribution networks.

Findings

Enhanced estimation accuracy compared to independent methods

Effective reconciliation of boundary voltage and power mismatches

Demonstrated scalability in large integrated systems

Abstract

Current transmission and distribution system states are mostly unobservable to each other, and state estimation is separately conducted in the two systems owing to the differences in network structures and analytical models. The large-scale integration of transmission and active distribution systems calls for an effective solution to global state estimation. Unlike existing independent state estimation methods on both levels of these systems, we propose a decentralized coordinated transmission and distribution system state estimation (C-TDSE) method. This method enables accurate monitoring of the integrated systems with a global reference in a decentralized manner and reconciles the mismatches of voltages and powers on the boundaries of the systems. The comparative analysis on the integrated transmission and distribution systems points to improved estimation results relative to the independent state estimation methods.