Communication Circuits on 500-kV Lines

The characteristics of 500-kV transmission lines from a communication viewpoint are discussed based on tests and observations of the Tennessee Valley Authority's first 500-kV line to be placed in service. Dead-line carrier frequency tests included attenuation on the insulated shield wires and phase-coupled power-line carrier arrangements. Modal component attenuation, relative velocity of propagation, and other characteristics of natural mode behavior are covered. Experiences to date on operation of power-line carrier terminals and audio equipment are given, along with a brief resume of RI measurements.