Research On Power System State Estimation Based On PMU

With the application of GPS timing synchronized Phasor Measurement Units(PMUs)in power systems,PMUs are synchronized by satellites so that power system state estimation meets real-time requirements.The development of a power system state estimation algorithm that can make full use of SCADA and PMU measurement data,high calculation accuracy,and fast convergence speed plays a decisive role in the safe and reliable operation of the power grid.With the successful development of PMU devices and their application in power systems,there is an additional way to obtain power system state estimation measurement data.This paper describes in detail the research status of PMU measurement technology,the principle of PMU technology and the composition of WAMS system.The current power system measurement device is mainly composed of SCADA device and PMU device.The optimal configuration scheme of the measurement device and the time and phase angle conversion processing methods of the two measurement devices are introduced.The traditional state estimation method uses the real-time measurement data including bus voltage,branch power flow,and node injection power flow to estimate the voltage phasors of each bus of the system.These real-time measurement data mainly come from the SCADA measurement system.The application of a PMU device that is time-provided by the GPS in the power system requires the relevant technology to apply the PMU measurement data with higher accuracy to the state estimation.This paper proposes a power system state estimation method that can make full use of SCADA measurement data and PMU measurement data.This method can be used to process branch current measurement data in rectangular coordinates and polar coordinates.Therefore,the error caused by the measurement transformation can be eliminated.The validity of this algorithm is verified by IEEE-14 node system.Since the number of nodes in the power system is relatively large,the PMU device installed at all nodes is economically inferior.In this paper,with the minimum number of PMU devices to make the system fully observable,a PMU optimization configuration method based on integer programming algorithm is proposed.The optimal installation location of the IEEE-20 node system PMU is solved by this method.The results show that the algorithm has certain advantages compared with the traditional integer programming algorithm.