Research On State Estimation For Distribution Network Using CIM

In recent years, with a variety of advanced technology widely used in the power grid, Smart Grid has reached a consensus in the world and become an inevitable trend of development. The automation level of distribution network, which links the power grid and the users as an important part, is one of the hallmarks of Smart Grid. State estimation is an integral part of distribution management system. Meanwhile, to achieve software integration and information sharing for EMS/DMS, the International Electrotechnical Commission issued standard IEC61970/61968. The standard has created a Common Information Model (CIM).Owing to the three-phase imbalance feature of distribution network, maturity algorithms for transmission network cannot be used. Three-phase state estimation for distribution system of radiation-type is needed to study. In addition, the distribution network state estimation should be consistent with CIM model to meet the intelligent development of the DMS system.First, this paper describes the background of the state estimation for distribution network and gives an overview of its international development. Then the Common Information Model (CIM) and how to achieve interoperability of CIM/XML model in EMS/DMS systems are stated. After that, the three-phase model of electrical element and the equipment model in CIM model are described in detail. Finally, this paper analyzes and implements the topology analysis and state estimation based on CIM for the distribution network in the last two chapters.The CIM-based topology analysis of the distribution network uses the depth-first search method to implement the global and local topological analysis on the basis of CIM model. That can construct real-time distribution network topological structure for the state estimation of distribution network. In the paper, the branch current-based state estimation algorithm is adopted for the distribution network state estimation. The algorithm not only simplifies the Jacobian matrix, but also achieves three-phase together with real and imaginary parts decoupling. That greatly improves the solution efficiency of state estimation.