A Model for Uprating Transmission Lines by Using HTLS Conductors

This paper presents a new method for calculating tensions and sags on a tension section with different conductors on level and nonlevel spans of equal or unequal lengths and at any temperature, including the situation where the conductor temperature varies on the entire tension section. The model involves the application of high-temperature low-sag conductors on specific spans. As the conductor temperature and electrical current are intrinsically associated with ground clearances, a comparative study of steady-state ampacity models and a sensibility analysis with meteorological parameters were performed. This method results in a gain of ground clearance as well as horizontal tensions less than those calculated for the original line, depending on the type of floating dead end used. The results of a cost-benefit analysis prove very attractive, since the original conductors would not be discarded. Added to which, the large-scale installation of new towers is not necessary. The developed model represents, therefore, a significant contribution to low-cost uprating of transmission lines while, at the same time, avoiding the need to expand the transmission system.