Abstract: The present invention realizes an increase of the capacity of a power transmission wire without replacing an already strung aerial power transmission wire. For this purpose, a braided heat conducting wire heat dissipating belt (1) treated to blacken its surface so that a surface heat dissipation rate becomes 0.7 or more or a surface-blackened heat dissipating spiral rod is wound around an outer circumference of an already strung aerial line (2) or jumper (8) so as to increase the heat dissipation effect of the surface of the aerial line (2). Heat dissipation enables the capacity of a permissible power supply of the already existing aerial line (2) to be increased. Further, the braided heat conducting wire heat dissipating belt (1) shares the transmission function and lowers the wind noise.

Abstract: An overhead cable includes an outermost surface formed by twisting together a plurality of segment strands. A plurality of spiral grooves form recesses having substantially rectangular cross-sections and are provided at intervals in a circumferential direction of either the outer surface of the segment strands or the outer surface regions of boundary portions where twisted segment strands adjoin each other. Thin segment strands and at least one thick segment strand form the outermost layer. A recessed portion is provided at one side surface among two surfaces of the segment strands forming the outermost layer, a projecting portion is provided at the other side surface, and the strands are twisted together so that the recessed portions and the projecting portions mate.

Abstract: An overhead power transmission line formed by stranding at least one outwardly projecting strand at the outermost layer of an overhead power transmission line formed by a plurality of strands. At least the outwardly projecting portion of the outwardly projecting strand is composed of an organic material. The outwardly projecting strand has a projection height H within a range defined as 1.5 mm≦H≦7.0 mm. By setting the projection height H of the outwardly projecting strand equal to or larger than 1.5 mm, the wind noise characteristic can be conspicuously improved. Further, by setting H≦7.0 mm, the outwardly projecting strand comprised by an organic material is made easily crushable, so the gripping portions of spacers, dampers, and other parts which have been conventionally used can be used as they are.

Abstract: An overhead power transmission line formed by stranding at least one outwardly projecting strand at the outermost layer of an overhead power transmission line formed by a plurality of strands. At least the outwardly projecting portion of the outwardly projecting strand is composed of an organic material. The outwardly projecting strand has a projection height H within a range defined as 1.5 mm.ltoreq.H.ltoreq.7.0 mm. By setting the projection height H of the outwardly projecting strand equal to or larger than 1.5 mm, the wind noise characteristic can be conspicuously improved. Further, by setting H.ltoreq.7.0 mm, the outwardly projecting strand comprised by an organic material is made easily crushable, so the gripping portions of spacers, dampers, and other parts which have been conventionally used can be used as they are.

Abstract: A top phase transmission line and bottom phase transmission line are stretched between support steel towers so that the bottom phase transmission line is positioned below the top phase transmission line. Each of the transmission lines has at least two conductors, which conductors are arranged to be substantially parallel and are separated by a substantially constant distance by interconductor spacers. An intermediate phase transmission line may be arranged between the top phase transmission line and bottom phase transmission line as well. Such transmission lines are multiconductor transmission lines. In these multiconductor transmission lines, the conductor positioned at the left side in the top phase transmission line and the conductor positioned at the right side in the intermediate phase transmission line or bottom phase transmission line directly below it are connected by a first interphase spacer made of an insulator.

Abstract: A multiple-cable power transmission line system is provided which includes a plurality of overhead transmission lines each having a ridge on the outer periphery thereof. When the outer periphery-to-crest height of the ridge of an overhead transmission line which is located closer to the earth ground is LE and the outer periphery-to-crest height of the ridges of the other overhead transmission lines is L.sub.OT, the relation L.sub.E <L.sub.OT is fulfilled.

Abstract: An overhead cable provided with a plurality of segment strands of a sector-shaped cross-section twisted at the outermost layer and having grooves of a substantially arc-shaped cross-section at the surface at the adjoining portions of the segment strands. Also, a low sag, low wind load cable provided with tension-bearing cores comprised of strands having a linear expansion coefficient of -6.times.10.sup.-6 to 6.times.10.sup.-6 /.degree.C. and an elastic modulus of 100 to 600 PGa and with a plurality of sector-shaped cross-section segment strands twisted around the outermost circumference of the cable including the tension-bearing cores comprised of a super-high-heat resisting aluminum alloy or extra-high heat resisting aluminum alloy, grooves of a substantially arc-shaped cross-section being provided at the surface at adjoining portions of the twisted segment strands. This enables the wind load to be reduced. Further, a low wind load cable can be easily fabricated at a low cost.