JPH09275619A - Method for preventing wind noise of multiple-conductor transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent neighboring electric wires with a spiral strand wound from attracting and colliding with each other by an electromagnetic force on occurrence of a short-circuit failure and thereby to prevent the wound spiral strand from damaging the electric wires, when the prevention of wind noise is attempted by winding a spiral strand on each transmission line arranged in parallel. SOLUTION: A space between electric wires 1 constituting multiple-conductor transmission lines is maintained by spacers 2. In a span between the two spacers (called a subspan), the middle part of the subspan is wound with a spiral strand 4 to the reverse direction against the laying direction of an electric wire, but both ends of the subspan closer to the spacer mounted parts are wound with a spiral strand 3 to the same direction with the laying direction of the electric wire. This winding method applies to each subspan and each electric wire arranged in parallel. If a short- circuit occurs, the middle parts of the subspan attract and collide with each other. However, the spiral strand wound on the electric wire to the reverse direction does not bite into the electric wire so that a damage to the wire is reduced. In term of the longitudinal direction, this winding method is effective to prevent vibration and wind noise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wind noise preventing method for reducing electric wire wind noise of an overhead power transmission line, particularly a multi-conductor power transmission line.

[0002]

2. Description of the Related Art As a wind noise prevention method for a multi-conductor transmission line in which a plurality of transmission lines are arranged in parallel, a method of winding a spiral wire around an electric wire is used. FIG. 3 shows a specific example thereof. The electric wires 1 and 1 arranged in parallel are held at intervals by spacers 2 and 2. The electric wires 1 and 1 are spirally wound in the longitudinal direction in the same winding direction as the electric wires.
And the spiral wire 4 in the winding direction opposite to the twisted direction of the wire.
And are alternately wound at every spacer interval. on the other hand,
In the electric wires arranged adjacent to each other, the spiral strands are wound in opposite directions at intervals of the spacer.

[0003]

In a multi-conductor transmission line, when a short-circuit accident or the like occurs, a phenomenon occurs in which adjacent electric wires are attracted by electromagnetic force. When a phenomenon occurs due to such an accident, the wire holding point and the spacer attachment point, or the two spacer attachment points are used as fixing points, and the electric wire portion (called a sub span) sandwiched between them is directed from the center to the fixing point. Are attracted in the longitudinal direction, the electric wires collide with each other, and the electric wires are damaged by the spiral wire wound around this portion. In particular, when the electric wire collides with the spiral wire winding portion in the same twist direction as the electric wire, there is a possibility that significant damage may occur such as the spiral wire getting into the eyes of the electric wire. An object of the present invention is to improve the damage caused by the spiral strands generated when the electric wires collide with each other due to a short circuit accident or the like.

[0004]

The electric wire collision phenomenon does not occur in the vicinity of the electric wire holding portion or the spacer mounting portion because the mutual distance between the electric wires is fixed, and is limited to the intermediate portion. The present invention pays attention to this point, and a spiral wire opposite to the twist direction of the electric wire is wound around the intermediate part where the collision phenomenon occurs, and even if the electric wires collide with each other, the spiral wire gets into the eyes of the electric wire. There is no such thing. In addition, by winding the spiral strand in the same direction as the twist direction of the wire at the part of the wire that is adjacent to the retaining part or the spacer mounting part, the vertical lift generated in the wire is balanced in the longitudinal direction of the wire. Effect (aerodynamic stability)
The wind noise can be prevented.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described with reference to FIG. The electric wires 1 and 1 forming the multi-conductor transmission line are spacers 2.
The spiral wires 3, 4 are wound around the outer circumference of each electric wire. Generally, the twist direction of the wire is more than s (from the right), so in the middle part of the sub-span where the wires may collide with each other, the spiral strand from z (from the left) opposite to the twist direction of the wire Wind 4. Further, the spiral strand 3 having the same s as the twist direction of the electric wire is wound around both ends of the sub-span adjacent to the retaining portion of the electric wire and the spacer mounting portion. Such a winding method of the spiral wire is applied in the same manner in each sub-span and in each parallel electric wire.

A winding length l of a spiral wire wound around a portion adjacent to a wire holding portion or a spacer mounting portion.
(L) is slightly different depending on the line conditions such as the wire size, wire spacing, wire tension, and short-circuit current that compose the multi-conductor transmission line. Since the length that the electric wire does not adsorb is about 2 m, the range is about 2 to 10 m. Further, since the sub-span length is about 30 to 50 m, the winding length l (ell) is appropriately about 5 m in consideration of aerodynamic stability. FIG.
Shows the state where the electric wire adsorption phenomenon occurs due to the short-circuit current.

The spiral strand is usually wound by adding a standard length product of about 2.5 m, but the spiral strand wound around both ends of the sub-span has a large curvature when the wire attracts the wire. It is more effective to prevent the joint from coming off by winding it with a long product without additional joints. An optimum winding length 1 (L) is 5 m for a subspan length of 30 to 50 m, and a long product having a length twice or more that of the standard product is suitable.

[0008]

With the recent increase in the transmission capacity, the collision force of the electric wire at the time of a short circuit accident also increases, and there is a concern that the electric wire may be damaged. According to the present invention, even if the electric wires collide with each other at the time of a short circuit accident. It is possible to reduce the degree of damage to the electric wire due to the spiral strand, and to secure the aerodynamic stability of the electric wire to suppress vibration and prevent wind noise.

[Brief description of drawings]

FIG. 1 is a plan view showing an outline of a wind noise prevention method of the present invention.

FIG. 2 is a plan view showing a state where an electric wire attraction phenomenon occurs due to a short-circuit current.

FIG. 3 is a plan view showing an outline of a conventional wind noise prevention method.

[Explanation of symbols]

 1 Wire 2 Spacer 3 Spiral element wire in the same winding direction as the wire direction 4 Spiral element wire in the winding direction opposite to the wire direction

Claims (5)

[Claims] 1. A method for preventing wind noise of an electric wire by winding a spiral wire around the outer circumference of each electric wire constituting a multiconductor transmission line, wherein a spiral is provided in an intermediate portion of the subspan in a direction opposite to a twist direction of the electric wire. Wrap the strands of wire, and at both ends of the subspan adjacent to the wire holding part or spacer mounting part,
A method for preventing wind noise of a multi-conductor transmission line, which comprises winding a spiral wire in the same direction as the twist direction of the electric wire. 2. A long product which is longer than a standard length product used for a spiral wire wound around an intermediate portion of a spiral wire wound around both ends of a subspan adjacent to an electric wire retaining portion or a spacer mounting portion. The method for preventing wind noise of a multi-conductor power transmission line according to claim 1, wherein 3. The length of a spiral wire wound around both ends of a sub-span adjacent to the wire retaining portion or the spacer mounting portion is at least twice as long as the standard length product used for the spiral wire wound around the middle portion. The method for preventing wind noise of a multi-conductor transmission line according to claim 1, wherein the method is a long product. 4. The multifilar wire according to claim 1 or 2, wherein the length of the spiral wire wound around both ends of the sub-span adjacent to the wire retaining portion or the spacer mounting portion is in the range of 2 to 10 m. Wind noise prevention method for conductor power lines. 5. The multiconductor transmission line according to claim 1, wherein the length of the spiral wire wound around both ends of the sub-span adjacent to the wire retaining portion or the spacer mounting portion is 5 m. Wind noise prevention method.