Research On Power System State Estimation Algorithm

State estimation is the basic content of the advanced application software used in the modern energy management system (EMS), it provides the basic data for other EMS advanced software which can make the voltage stability analysis, security constrain dispatch and transient stability analysis. Therefore, it’s significant to research state estimation algorithm.The traditional state estimation algorithm is based on the supervisory control and data acquisition (SCADA) system to collected measurement data, to solve the iteration method of nonlinear equations obtained the best estimate the system state variables, namely the bus voltage amplitude and phase Angle.The traditional state estimation algorithm is according the collected measurement data which is based on the supervisory control and data acquisition (SCADA) system to solve the nonlinear equations by iteration method for the best estimation of the system state variables, namely the voltage amplitude and phase angle of the bus. The emergence of synchronous phasor measuring units (PMU) takes great effect on the power system state estimation, the PMU realizes that the state variables can be measured directly in the state estimation, which leads the change of state estimation algorithm corresponding.In the first, This paper described the measurement system, electric power network and network equations on the power system state estimation; Then studied three kinds of classic power system state estimation algorithm, made simulation based on the theory of the three classical algorithm, the simulation data was analyzed and compared; After that, Seriously studied the existing state estimation model which introduced the PMU measurement information, on this condition, a state estimation model that was based on the PMU and SCADA for mixed measurement was put forward, using the equivalent current measurement varying algorithm in polar coordinates to deal with the PMU measurement information and the original SCADA measurement in four aspects. Simulated the model in IEEE14node system by MATLAB, the results of data are analyzed and compared, the last simulation results show that the model is effective and optimize the filtering effect to some extent.