EHV transmission line design opportunities for cost reduction

The authors consider a range of line optimization techniques which can be applied to decide whether standard or optimized line designs are appropriate. It is found that even simple methods of optimization can help the designer keep costs to a minimum. The effects of electrical losses, structure family and heights, and conductor design limits on temperature and tension are determined in flat and hilly terrain for a 500 kV example. In the example, in flat terrain, the selection of an optimum design in place of the standard results in savings of from 8% to 15% in the total present worth of revenue required for construction and losses over the life of the line. In a specific section of hilly terrain, the example shows that the use of optimization methods results in savings of from 15% to 19%. It is noted that the costs of redesigning structures, using nonstandard conductors, and investigating the proposed changes in design limits must be measured against such potential savings