Investigation of frequency-dependent impedance and admittance of 110-kV overhead lines using symmetrical components

The central objective of this paper is to investigate the harmonic behavior of 110-kV overhead lines. For this purpose, a method to describe the frequency-dependent series impedance and shunt admittance per unit length has been developed using the symmetrical components. The developed method uses input data that has been generated using the simulation software PSCAD. This paper begins by presenting the equations to describe overhead lines using the phase domain. It continues with the transformation of these phase domain equations to the symmetrical components equations. In the last section of the paper, results are presented. The main characteristics of the positive, negative and zero sequence series impedance and shunt admittance are addressed in terms of physical principles. Furthermore, the magnetic and electric coupling between the sequences of one circuit or both circuits of the simulated overhead lines are also thoroughly discussed.