Estimation of the Frequency-Dependent Parameters of Transmission Lines by Using Synchronized Measurements

Transmission line parameters are usually calculated based on technical and environmental approximations, e.g. line height, cable conductivity, etc. These characteristics vary depending on the environment and technical issues, meaning that the transmission line should be considered as a dynamic system with time-varying parameters. Estimation methods are a useful way to determine line parameters taken into account such characteristics. Most methods estimate these parameters at 50 ~ 60 Hz, useful for steady state analysis. However, for transient state or harmonic distortion analyses, a frequency range should be estimated, which varies according to the phenomenon to be investigated. In this matter, considering the gap existent of studies to estimate frequency-dependent parameters, we propose an efficacious and simplified method based on the two-port line representation and the well-known least squares method to estimate these parameters of a transmission line with 400 km length, considering a minimum number of synchronized measurements from 1 Hz up to 250 Hz.