Double Conductors for Transmission Lines

When two overhead conductors a few inches apart are used for each phase of a transmission line circuit, instead of one larger conductor, the reactance is reduced-20 per cent or more. Where voltage drop determines the maximum power load, as it does in many cases, reduced reactance is advantageous and increases the allowable power rating. Current-carrying capacity and corona voltage are increased. The advantages are to be balanced against the extra cost due to mechanical features, including hangers, increased cost of stringing and additional wind and ice load. Since increase in ice load is possibly the greatest disadvantage, the use of double conductors is of most interest for southern districts, where ice load is not encountered.