Some problems in transmission-line design

The paper gives particulars of some serious damage caused by snowstorms to transmission lines in Ireland and of consequent departures from conventional design. The factors governing the examination of breakdown data are critically analysed and the data and conclusions for particular cases are briefly stated. Loadings are compared with those specified by the British Regulations for Overhead Lines, and the effectiveness of the universal method of controlling the factor of safety of conductors is challenged. The superiority of a horizontal over a triangular arrangement of conductors is viewed from a new angle, and the reasons for adopting a horizontal arrangement on wood poles for 260 miles of 110-kV line are given. Various problems in connection with the design of this line are set out, costs are given and the conclusion is drawn that it is much more economical than a line carried on lattice steel towers.