| The rapid development of the national economy and the improvement of people's life raise a new requirement of power quality and service reliability,which expects to realize distribution automation (DA). With the development of distribution automation,it is much necessary to mprove the capability of supervising distribution networks in real-time,Researches on DSE are carried out in the thesis and the following work is done:1. The distinctions between DSE and transmission state estimation (TSE) are introduced after showing the characters of distribution networks and transmission networks. How to model electric power elements,such as power lines,transformers, capacitors and loads in the distribution system is discussed in details in this thesis because the performance of DSE rests heavily on the accurate models of them.2. The fundamental principles of DSE are expounded and the metrics and drawbacks of currently popular algorithms including WLS, method based distribution matching power flow,method based transformed measurement, WLAV are compared in the terms of accuracy,algorithm convergence,speediness and requirement of memory.3. A new local algorithm of DSE is proposed. This method divides the whole networks into several subsystems by structure of network and locations of remote-meter measurements; subsequently each subsystem can be decoupled into real and imaginary parts based on transformed measurement. Compared with the tradition methods , great improvement in the DSE execution time can be obtained by using this scheme,which makes DSE more efficient.4. The guidelines about how to locate the remote-meter measurements are also given.5. DSE program is developed,which has been tested for its efficiency.
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