Stepwise robust distribution system state estimation considering PMU measurement

Abstract

In order to deal with the problem of robustness and computing speed of distribution system state estimation with the development of phasor technology, a stepwise distribution system state estimation with robust performance and considering real-time phasor measurement unit (PMU) measurements is proposed. The proposed method utilizes the absolute value of residuals to construct the weight function and uses the unit weight variance to standardize the residuals so that the residual precision can be unified on the same scale to improve robustness. Besides, the state estimation is divided into two steps. The first step makes use of supervisory control and data acquisition (SCADA) measurements and branch current phasors measured by PMU to perform the robust estimation, and due to the high sparsity of the Jacobian matrix, the computational efficiency can be ensured. The second step combines the estimation results of the first step with the voltage phasors measured by PMU to perform linear state estimation, which can update the result of the first step and realize the combination of SCADA and PMU measurements in the state estimation. Finally, the proposed method is verified by the Institute of Electrical and Electronics Engineers (IEEE) standard systems.