Robust State Estimation Using Node-Breaker Substation Models and Phasor Measurements

A least absolute value (LAV) based linear state estimation (SE) algorithm that can reject simultaneous topology and measurement errors is presented. The substations are explicitly modeled including every zero-impedance branch and circuit breaker (CB) in the network, eliminating the need for a topology processor. The network is assumed to be fully observable and measured by phasor measurement units. The conventional state vector formed by voltage phasors is augmented with CB flows to enable direct estimation of the open/close statuses of CBs. The observability analysis is carried out as part of the basis selection process of the Simplex algorithm. Two optional post-estimate statistical formulations, one for rejected measurements and the other for normalized CB flows, are devised to analyze the SE estimate in a systematic manner. A 300-bus IEEE system is used to demonstrate the capabilities of the proposed algorithm first for topology errors alone and with coincident bad measurements subsequently.