500-Kv-Line Design

Joint studies of the economic and electrical performance of high-altitude bundled conductors have been undertaken by the Pacific Gas and Electric Company and the General Electric Company as part of a comprehensive investigation of 500-kv-line design practice.1,2 Economic studies show the total annual cost of alternative conductors to be nearly constant over a considerable range of conductivities, but it is determined that a 2-conductor bundle of at least 1.600-inch diameter is required to assure reasonable fair-weather corona loss at a maximum operating voltage of 550 kv. Radio noise studies show a 1.600-inch subconductor to be satisfactory at 550 kv, provided that a surface factor of at least 0.75 is achieved through careful stringing.