An Algorithm Research Of Distribution System State Estimation

This thesis focuses on the fundamentals of radial distribution system state estimation (DSE), taking full advantage of radial characteristic of the distribution system to solve several problems in this field. A robust estimation algorithm based on branch-current is developed, and the model of the method is implemented with the techniques of object oriented.Firstly, the thesis analyzes the difference between transmission system and distribution system, studies the models of the distribution lines, transformers, capacitors and loads deeply.Later, the theory fundamental and mathematics model are introduced, and the techniques related to DSE are analyzed general.After that, a feasible DSE based on Newton Laphson method is proposed, which chooses the magnitude and phase angle of the branch current as the state variable. The algorithm decouples three phase easily, which is computationally efficient, and takes any type of measurements into account, including the voltage magnitude measurement. In the process of iteration, the idea of robust estimation introduced in the method resists the gross error in load data from load forecasting.At last, the thesis analyzes the model of the proposed method and the method based on equivalent current measurement based on object oriented, and implementing the methods with C++.