Tennessee Valley Authority's 500-kY System -Transmission Line Design

The Tennessee Valley Authority (TVA) recently completed construction of an approximately 155-mile 500-kV transmission line, which began commercial operation May 15, 1965. Principal features of the line, which consists of three conductors per phase supported by a free-swinging string of 24 ball-and-socket insulators, are described here. Rigid aluminum alloy spacers maintain the equilateral configuration, and two Alumoweld ground wires, insulated from the towers to provide for future communication channels, serve as shielding for the line. The square-base, waisted, self-supporting steel towers have a minimum 40-foot phase spacing.