Distributed quasi-dynamic state estimation with both GPS-synchronized and non-synchronized data

The distribution system always contains GPS-synchronized data and non-synchronized data. The application of both types of data in state estimation increases redundancy and accuracy of the estimated states. Using both GPS-synchronized and non-synchronized data, this paper introduces object-oriented distributed quasi-dynamic state estimation (DQDSE), which tracks slow dynamics (e.g., electromechanical transients of rotating electrical machines, controls of power electronics, etc.) while neglecting fast electromagnetic transients. DQDSE offers an efficient and practical way of performing state estimation for subsystems with phasor measurement units and other meters. It also transmits generated results to the control center for system automation and control. The advantages of DQDSE follow: (1) It uses a highly accurate system model, (2) it deals with unbalanced operating conditions, and (3) it uses local measurements to reduce state estimation computation time. The demonstrative example verifies the effectiveness of DQDSE.