Effects of Earth Resistivity on Modal Parameters of an EHV Horizontal Line at PLC Frequencies

A brief comparison of the salient aspects of modal analyses of lossless and lossy lines is described. Simplified equations for modal parameters of a three-phase horizontal line are demonstrated. Effects of earth resistivity, Pe, on the modal attenuations and velocities of propagation on a 500-kV line are discussed for Pe from 20 ¿m to 2000 ¿m at three frequencies, F: 50kHz, 100kHz and 200kHz. Modal voltage components, general and modal reflection-free line terminations are derived and compared with those for the lossless line. It is found that angles of all modal complex parameters and of line terminations are small.