Parameter Estimation for Line Impedance in Distribution Network Based on μPMU Data

Abstract

In order to solve the long standing issue of missing line impedance parameters in low voltage distribution network, this paper proposed a new approach based on measurement data collected from the micro-synchronous phasor measuring unit (μPMU). Firstly, by taking line impedance parameters as variables, the root node state value of the station area is calculated from the measurement data. And then by setting the objective function as the minimization of the difference between the calculated value and the measured value, the solution for impedance parameters is converted to a multi-objective optimization problem. Moreover, through designed experiments the weight coefficients of the objective function and the size of the dataset are determined appropriately to reduce the influence of errors on the solution results such that the model can be solved with higher accuracy. Finally, an example of a low voltage distribution network with 26 load nodes and 34 line branches is set up. Considering the actual measurement error, the average error of the line impedance parameter estimation is 3.87%. The case study results show that the proposed method achieves accurate estimation of the impedance parameters and hence the effectiveness of the proposed model is verified.

Keywords

• low voltage distribution network
• power line parameters
• multi-objective optimization
• micro-phasor measurement unit
• steepest descent method