Economy in the choice of line voltages and conductor sizes for transmission lines

Fundamentally, the choice of line conductors and of line voltage for any transmission line is based upon economic law. While the law is simple enough, its application is quite involved. A mathematical statement of the law as applied to transmission line design was presented in a previous paper¹ but the utility of the conclusions there reached was somewhat limited by the lack of suitable constants. The present paper provides suitable constants through which the application of the theory previously developed is extended to all types of transmission line conductors now in general use in America The paper concludes with a set of calculated curves for which the most economical line voltage and the most economical conductor area can be read off for a transmission line project of any assumed length and transmitting any assumed amount of power. The results obtained from the curves are found to agree very well with good engineering practise.