Distribution Network State Estimation Method Based On ?PMU And AMI Hybrid Measurement

With the large-scale integration and application of controlled loads including distributed generation(DG),electric vehicle(EV),energy storage system(ESS),the distribution network has the ability to actively adjust.In order to realize coordinated operation and control of the distribution network,it is necessary for distribution system state estimation to provide accurate states so that the real-time state of the perspective system can be perceived.With the micro-phasor measurement unit(?PMU)and advanced metering infrastructure(AMI)gradually applied to the distribution network,AMI and ?PMU provide distribution network with a large amount of real-time measurements.So study on distribution network state estimation based on ?PMU and AMI hybrid measurement that has important practical significance.Firstly,this paper introduces the distribution network measurement system of ?PMU and AMI,and summarizes the characteristics of ?PMU and AMI measurement data.According to the difference of sampling steps between ?PMU and AMI,the data fusion of ?PMU and AMI measurements is performed.Secondly,a real-time network topology analysis method based on ?PMU current measurement is proposed.The ratio of the effective value of the critical branch current measurements by ?PMU is compared with the switching coefficient of the switch to identify the topology change of the distribution network.Then modify the switch matrix of the network topology and the node branch association matrix to realize real-time network topology analysis.This method ensures the accuracy of topology analysis.The accuracy and effectiveness of the proposed method are simulated by different scenarios based on IEEE 33 test system.Thirdly,according to the typical configuration of the medium and low voltage distribution network measurement system,the parameters estimation methods of different wiring modes such as the main line,the medium voltage distribution network T-connection line,and the low voltage distribution network multi-branch line are studied.The parameter estimation is proposed according to different measurement data.The model is used to estimate the main line parameters of medium voltage distribution network based on AMI power information.The parameter estimation method of T-connection line with multi-time ?PMU and AMI hybrid measurements is proposed,and the parameter estimation method for multi-branch line equivalent model of low voltage distribution network is explored.The effectiveness and feasibility of the proposed method are verified by different typical examples.Finally,a node voltage state estimation algorithm based on hybrid measurement is proposed.Considering measurement fusion based on sampling step difference,determine the measurement type of the state estimation input data of the medium and low voltage distribution network,and modify the weight coefficient of each measurement,the corresponding measurement equation and the corresponding Jacobian matrix are established,and the Jacobian matrix is simplified for the parameter characteristics of the medium and low voltage distribution network.The proposed method is validated by the extended IEEE 33 example system.The simulation results show the effectiveness and feasibility of the proposed method.