Overhead Line Parameter Estimation Through Synchrophasor Data In Near Real-Time

The focus of this paper is on the verification of positive and zero sequence transmission line parameters through synchronized current and voltage phasor measurements on both line ends. An algorithm with phase-mode transformations developed earlier for a transposed line is utilized to reveal the influence of biased errors in synchrophasor data on the computed line parameter estimates. The analysis is carried out for both transposed and untransposed line models. The measurement errors are shown to have a strong influence on the algorithm outcome. A new line parameter estimation method exploiting the linear least squares technique is developed and tested out. The advantages of this new approach for positive sequence line parameter estimation are clearly shown. The key part of the paper is devoted to the results of a few tests with a black box modeling approach: real synchrophasors sourced from phasor measurement units on both line ends are taken to calculate the positive sequence line parameters. The series inductance and shunt capacitance are shown to have been estimated accurately, with the errors not exceeding 4% most of the time.