State Estimation For Distribution System

With the development of distribution automation system and distribution management system, it is more and more important to apply state estimation for distribution systems(DSE) to practical situation. There are many different features between distribution systems and transmission systems, so the state estimation technology used in transmission systems cannot be directly used in distribution systems. The main content of this paper is listed as follows:1. The actuality and challenges of DSE are analyzed.2. Considering the imbalance of three phase and large scale of distribution systems, three phase models of equipment are set up, as well as a simplified net model.3. Because there are not enough measurements, the observability of distribution system is poor. Pseudo measurements must be added in. A high-precision method of very-short-term load forecasting which is based on time series method is introduced.4. The basic methods for distribution flow and the theory of state estimation are discussed. A branch-estimation-based method aimed at radial network is analyzed and deducted to three-phase model. The new method has high precision and can handle more kinds of measurements.5. A system for DSE which is based on a graphical interface is realized. Some test cases are caculated and analyzed.