Estimation of Transmission Line Parameters Using PMU Measurements

Transmission line parameters are affected by several factors, such as ambient temperature, mutual coupling of parallel lines, and erroneous transmission line length. Further, the several joints, especially at the line ends, cause additional changes in the calculated line parameters. These factors are rarely taken into consideration resulting to obsolete line parameter databases. The error that is encompassed in the values of the transmission line parameters can be up to 30% of their nominal value. In this paper, a methodology for estimating the actual parameters of transmission lines represented as a nominal pi model is proposed. In this methodology the PMU measurements at the one end of the line and the estimated states from a hybrid state estimator for the other end of the line are required. The proposed methodology is applied to the IEEE 14 bus system and the results are demonstrated in this paper.