AC Resistance Evaluation, Measurements and Savings of Innovative Bare Conductors

The continuously growing electrical power demand is more and more faced by the increase of generation from renewable energy sources. Given the difficulties in building new lines, the development of new technologies for conductors is desirable in order to increase the ampacity and the efficiency of the existing overhead lines. For this purpose high temperature low sag conductors, optical phase conductors and conductors composed by different strands shape and dimensions it has been developed and are currently a main research topic. Substitution of traditional overhead lines conductors with innovative ones can play a key role in the reinforcement of transmission and distribution electric grids, allowing at the same time high environmental benefit, as reduction of CO₂ emissions. In order to predict accurately economic and environmental savings, it is important to demonstrate that the value of the estimated and calculated ac resistance is almost equal to the ac resistance in operating conditions. The present paper summarizes the variable of interest in the ac resistance evaluation for general stranded bare conductors, then a general ac resistance measurement process is defined and applied, measured values are compared with estimated values computed by means of codes. An approximated evaluation of economic and environmental savings due to the re-conductoring operation is carried out and the actualized costs of the energy losses for traditional and innovative conductors are computed and compared, with the aim to show the benefits of innovative conductors.