The Influence of Sleet upon the Long-Span Overhead Transmission-Line Wires

Abstract

Double-circuit towers for extra-high tension transmission lines, which are generally employed at present, have the conductor arrangement such that three wires in one circuit are placed nearly in a vertical plane. The author states the possibility of frequent troubles of line-to-line flash-over, if such ordinary type towers be used in a mountain district of deep snowfall with long tower-span, caused by the jumping up and resilience of one conductor by the sudden fall of sleet, or by the unbalanced loading between conductors in parallel. As a conclusion, the author explains that it is important not to arrange three conductors in one plane; on the contrary that the horizontal distance between those planes containing each conductor shall be kept not less than 2 feet for a 77, 000 volt line, and 4 feet for a 164, 000 volt line.