Distribution Network State Estimation Based On AMI Measurements

As fundamental equipment of advanced metering infrastructure(AMI),smart meters collect the power consumption information of users which provide system wide visibility for distribution network.Combining the AMI measurements with the traditional SCADA measurements can solve the problem of insufficient redundancy of measurements,however,it also leads to a series of compatibility problems in which the delay of measurements has the most prominent impact.In coping with these problems,this paper proposes a method of distribution system state for medium-voltage and lowvoltage distribution network.The main works of this paper are shown below.(1)As the line parameters and load of the three-phase distribution network are unbalanced,the models of three-phase components are described in this paper firstly.Taking the voltage amplitude and phase angle as state variables,the expressions of the node voltage,the injection power,the branch power,correction equations of Newton Method and the Jacobian matrix are deduced and proved.(2)Considering the measurement characteristics of AMI and SCADA,a series of integrated distribution state estimation methods for medium-voltage and low-voltage distribution network are put forward aiming at online or offline scenarios respectively.The nonsynchronized measurements are selected in order to achieve a higher accuracy level for estimation.(3)The model of nonsynchronized measurements are simulated with the actual residential loads taken by high resolution meters and typical daily load profiles of distribution transformers.With the above information,the measurement weights are tuned and the 95% confidence intervals of the network states are estimated for each scenario and time segment.