State Estimation Method for Power System with a Large Number of Branches Using Voltage and Current as State Variables

Abstract- A power system state estimation is a key tool for a reliable and efficient management of electrical power. This paper presents based on new state variables a state estimation method for power system with a large number of branches. In this method, the node voltage and the active current and reactive current of branch are chosen as the state variables. Therefore, measurement functions of ampere and voltage are significantly simplified and no measurements transformation is needed in this method. The observability analysis indicates the proposed method can be used in power system with very limited measurements. Numerical tests on power system with the radial and meshed network show the real-time branch current measurements can significantly improve the accuracy and computation speed of estimation results.