A Network Partition Approach for Distributed Three-phase State Estimation of Active Distribution Networks

With the expanding scale and three-phase unbalance problem of active distribution networks (ADNs), traditional centralized state estimation (CSE) cannot meet the requirements of real-time analysis and control of distribution systems. This paper presents a network partition approach based on topology analysis algorithm for distributed three-phase state estimation (SE) of ADNs. Branch-line layer method and postorder-traversal algorithm are used to perform partition approach which considers radial topology structure and PMU configuration of distribution system. After network partition and decoupling, the local SE is performed based on weighted least squares (WLS) method in each decoupled region and data exchange is performed among adjacent regions to improve DSE accuracy. The distributed state estimation (DSE) has a better performance in accuracy and efficiency than CSE, which is tested in IEEE 33-bus and IEEE 123-bus distribution systems.