JPH05242734A - Galloping preventing type overhead transmission line - Google Patents

Abstract

PURPOSE:To prevent the galloping vibration of an overhead transmission line by stranding a conductive wire rod with a wire rod having different torsional rigidity. CONSTITUTION:An overhead transmission line is formed of aluminum wires 2 and copper wires 1, having different torsional rigidity therefrom, being stranded therewith so that the copper wire 1 is stranded eccentrically in one part of the outmost layer of the line. As the result, the torsional rigidity changes in a lengthwise direction, so that a torsional natural vibration cycle becomes unstable when ice and snow coat the line, and becomes difficult to synchronize with a natural vibration cycle in an up and down direction. Thereby a galloping vibration can be suppressed by the line itself. Accordingly, it is not necessary to attach a damper having heavy weight to the line, so that the weight loaded on steel towers can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead power transmission line in which galloping vibration is unlikely to occur.

[0002]

2. Description of the Related Art When a strong wind blows laterally on an overhead power transmission line and ice snow adheres to the windward side surface of the electric wire, the electric wire and the entire snow accretion form a wing-like cross section, which causes lift and a large amplitude. It is known that galloping vibration occurs. An important factor that causes large amplitude galloping vibration is the natural vibration period of the wire twisting during icing snow,
It has been confirmed experimentally and also by outdoor observation that the closer this becomes to the natural vibration period of the wire in the vertical direction, the more stable galloping vibration is likely to develop.

Therefore, as a method of preventing galloping vibration, conventionally, a damper that disturbs the twisting vibration cycle is attached to the erected electric wire, and the twisting vibration cycle of the icing and snow wire is defined as the natural vibration cycle in the vertical direction of the electric wire. A different method is implemented (Japanese Patent Publication No. 55-23006).

[0004]

However, the conventional method has the following problems. The damper for galloping vibration prevention weighs 50 to 10
There is 0kgf, and installation is extremely troublesome. Due to its weight, it greatly affects the strength of the tower,
It may not be installed depending on the strength of the tower. There is a risk that the damper may get entangled with the electric wire of the other phase and cause a serious accident due to lateral shake or three-jump.

Therefore, an object of the present invention is to provide an overhead power transmission line which does not need to be equipped with a galloping vibration prevention damper and which is unlikely to cause galloping vibration.

[0006]

To achieve this object, the present invention provides
It is characterized in that a conductive wire and a wire having different torsional rigidity are twisted together, and the wire having different torsional rigidity is eccentrically twisted around a part of the outermost layer.

[0007]

By doing so, since the torsional rigidity of the wire changes in the longitudinal direction, the twisting vibration cycle of the wire during galloping vibration becomes unstable, and it becomes difficult to synchronize with the natural vibration cycle of the wire in the vertical direction. Galloping vibration is less likely to occur.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an embodiment of the present invention. This overhead power line consists of five aluminum wires 2 and 1 on the outer circumference of the central steel wire 1.
A steel wire 1 of a book is twisted together. The steel wire 1 has a significantly higher torsional rigidity than the aluminum wire 2, and only one steel wire 1 having a large torsional rigidity is eccentrically arranged in the outermost layer. Therefore, the torsional rigidity of this electric wire is It changes in the longitudinal direction depending on the position of the outermost steel wire 1.

FIG. 2 shows another embodiment of the present invention. This overhead power transmission line consists of four aluminum wires 2 on the outer circumference of the central steel wire 1.
And two aluminum-coated steel wires 3 are twisted together,
It is formed by twisting nine aluminum wires 2 and three aluminum-coated steel wires 3 together. The aluminum-coated steel wire 3 has higher torsional rigidity than the aluminum wire 2, and the two aluminum-coated steel wires 3 are eccentrically arranged in the middle layer, and the three aluminum-coated steel wires 3 are collectively arranged in the outermost layer. It is eccentrically arranged. For this reason, this wire also twists in the longitudinal direction and its rigidity changes.

FIG. 3 shows still another embodiment of the present invention.
In this overhead power transmission line, 7 cores of aluminum-coated steel wire 3 are arranged in the center, and 10 aluminum wires 2 are twisted around the outer periphery,
12 aluminum wires 2 and 4 aluminum-coated steel wires 3 on the periphery
The aluminum-coated steel wire 3a having a large twisted wire radial direction size is used for one of the four aluminum-coated steel wires 3.

In this electric wire, four aluminum-coated steel wires 3 having a higher rigidity than the aluminum wire are arranged eccentrically in the outermost layer, and one of them is an aluminum-coated steel wire 3a having a large stranded wire radial direction size. Therefore, the degree of eccentricity increases, and the degree of change in torsional rigidity in the longitudinal direction also increases. Further, since the spiral ridge is formed on the outer peripheral surface of the electric wire by the aluminum-coated steel wire 3a having a large size in the radial direction of the twisted wire, the Karman vortex is disturbed by the wind, and there is an advantage that slight wind vibration and wind noise can be prevented. ..

In each of the above embodiments, the aluminum wire is used as the conductive wire material, and the steel wire or the aluminum-coated steel wire is used as the wire material having different torsional rigidity from the aluminum wire, but the present invention is not limited to this. Absent. As the conductive wire, for example, aluminum alloy wire or copper wire can be used, and as the wire material with different torsional rigidity, iron wire with high electrical resistance, low Curie point magnetic wire, FRP wire, etc. can be used. Is. If iron wire with high electric resistance or low Curie point magnetic wire is used, it is possible to eliminate snow accretion due to its heat generation.

[0013]

As described above, in the overhead power transmission line according to the present invention, the torsional rigidity changes in the longitudinal direction, the twisting natural vibration cycle during icing and snowing is unstable, and the vertical natural vibration of the electric wire. Since it becomes difficult to synchronize with the cycle, the galloping vibration can be suppressed by itself. Therefore, it is not necessary to attach a heavy damper, and there is an advantage that the load applied to the steel tower can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an anti-galloping overhead power transmission line according to the present invention.

FIG. 2 is a sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing still another embodiment.

[Explanation of symbols]

 1: Steel wire 2: Aluminum wire 3: Aluminum coated steel wire

Claims (1)

[Claims] 1. A conductive wire rod and a wire rod having different torsional rigidity are twisted together, and the wire rods having different torsional rigidity are eccentrically twisted to a part of the outermost layer. An antigalloping overhead power line.