JP2003244829A - Insulation cover and insulating structure for base wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulation cover for a bare wire which prevents earth- fault accidents due to coming into contact with birds, trees, etc., and has a small wind loading and proper construction characteristics. <P>SOLUTION: The insulating cover covers the outer periphery of a bare wire. The insulation cover is a long sheet, with its both sides being provided with curl whose diameter is smaller than the outside diameter of the bare wire. It comprises an elastic material which provides such a restoring force as enabling the insulating cover to be attached in a coil form in the outer periphery of the bare wire, when the curl is opened. More specifically, it is preferable that it be constituted of silicone rubber, etc. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bare wire insulating cover such as a jumper wire and a bare wire insulating structure. In particular, the present invention relates to a bare wire insulating cover that can prevent a ground fault accident due to contact with a bird or a tree.

[0002]

2. Description of the Related Art Generally, in a jumper device for an overhead power transmission line, an arm member 32 is extended from a steel tower 31, and an insulator 3 and a retaining clamp 2 are attached to an end portion of the arm member 32, as shown in FIG.
The main line 4 is installed via the. The jumper wire 1 is suspended from the insulator 5, and is provided so as to connect the main wires 4 on both the supply side and the demand side. This main line 4
As the jumper wire 1, a steel core aluminum stranded wire (ACSR) or a hard copper stranded wire (HDCC) is used, and is usually a bare wire without an insulation coating. Therefore, when a bird such as a crow stops at the jumper wire 1 and spreads its wings, the arm member 32 of the steel tower 31
When touching or when a wire or the like is added as a nesting material and stops on the arm material 32, the tip of the wire may touch the jumper wire 1 to cause a ground fault accident. As a countermeasure, the arm member 32 and the jumper wire 1 are covered with an insulating cover.

An example of this insulating cover is shown in FIG. The insulating cover 20 is in the form of a sheet having a spiral curl, and has an inner surface provided with a ridge 21 extending in the axial direction of the spiral. The insulating cover 20 is used by winding it around the outer circumference of the jumper wire with the winding tendency open. The material of the insulating cover is ethylene propylene rubber, which has excellent insulating properties. The semicircular protrusion provided on the inner surface of the insulating cover can increase the creeping distance in the radial direction of the jumper wire.

Generally, the jumper wire is supported by the steel tower in a hanging state. Therefore, when the insulating cover 20 is used in such a bent portion, as shown in FIG. 4, the insulating cover 20 having a certain length is used. A plurality of jumper wires 1 are arranged in parallel to cover the outer circumference of the jumper wire 1. The joint of the insulating cover 20 is covered with a joint cover 22, and the cover is fixed by discretely stopping a plurality of places along the jumper wire with tightening bands 23.

[0005]

However, the above insulating cover has the following problems. It is difficult to attach / remove to / from the jumper wire. When the spiral curl is provided, the curling habit must be once solved until the innermost winding start when mounting on the jumper wire, and the mounting work is troublesome. Of course, when the insulating cover is replaced due to deterioration over time or damage, it is necessary to remove the curling tendency, and there is also a problem that workability is lacking.

It is difficult to attach the insulating cover along the bend of the jumper wire. As described above, the conventional insulating cover has a spiral shape that is wound in multiple layers, so it has poor flexibility, and it is very difficult to cover the entire length of the bent jumper wire with a single insulating cover. . Therefore, it is necessary to use a plurality of insulating covers and also a joint cover, which has been a factor of increasing the number of parts and complicating the mounting work.

The outer diameter when mounted on the jumper wire is large, and the wind pressure load is also large. A ridge is provided on the inner surface of the cover in order to increase the creepage distance in the radial direction of the jumper wire. As a result, there arises a problem that the outer diameter when the insulating cover is attached becomes large and the wind load of the jumper wire covered with the insulating cover becomes very large.

Therefore, a main object of the present invention is to provide a bare wire insulating cover which can prevent a ground fault accident due to contact with a bird or a tree and can be easily attached and detached.

Another object of the present invention is to provide a bare wire insulating cover which can be mounted along the bending of the bare wire.

Another object of the present invention is to provide a bare wire insulating cover which can minimize the outer diameter when the insulating cover is attached.

Further, another object of the present invention is to provide a bare wire insulating structure which can prevent a ground fault due to contact with a bird or a tree and which can be easily attached and detached.

[0012]

The present invention achieves the above object by devising the shape of the insulating cover.

That is, the insulation cover of the bare wire of the present invention is an insulation cover for covering the outer circumference of the bare wire, and the insulation cover has a long sheet shape, and the side edges thereof are smaller than the outer diameter of the bare wire. A curl having a diameter is provided, and when the curl is opened, the elastic cover is made of an elastic material that provides a restoring force that allows the insulating cover to be spirally attached to the outer circumference of the bare wire.

It has already been stated that the conventional spiral insulating cover lacks workability in mounting and removing. In the present invention, in a long sheet-shaped insulating cover, arcuate winding habits are provided on both side edges in the width direction, and an intermediate portion is formed into an arc having a diameter larger than the outer diameter of the bare wire or substantially linear. is doing. With this configuration, the curling habits on both side edges of the cover do not overlap in multiple layers like a spiral shape, and the curling habit can be relatively easily released. Further, since the widthwise intermediate portion of the insulating cover is substantially opened, fitting into the bare wire can be easily performed from this opening portion.

The material of this insulating cover is JIS K 6301.
Spring hardness test (A)
It is preferable that the value measured by the mold is 75 ° or less. In particular, it is preferably 65 ° or less, more preferably 55 ° or less. Of course, low hardness materials of 45 ° or less can also be used. When a material having a high hardness is used, the thickness of the insulating cover may be reduced, and when a material having a low hardness is used, the thickness may be increased. More specifically, fluororubber, silicone rubber,
At least one of urethane rubber, ethylene propylene rubber, and chloroprene rubber can be used. Silicone rubber and fluororubber are particularly preferable in terms of heat resistance and electric insulation. These rubbers are highly flexible and can be easily unwound, and an insulating cover can be attached along a bent bare wire. Therefore, it is not necessary to mount a plurality of insulating covers in parallel in the longitudinal direction of the bare wire,
No joint cover is required. Needless to say, when the bending diameter of the bare wire is small, a plurality of insulating covers may be used in parallel.

This insulating cover, when wound around a bare wire,
The thickness is selected so that the required withstand voltage characteristics can be obtained. As the thickness of the insulation cover, for example, for a bare wire with a transmission voltage of 77kV (voltage to ground 44.5kV, voltage to ground: AC three-phase three-wire system, 1 / √3 of line voltage),
A thickness of about 4.0 mm to 8.0 mm, particularly preferably about 4.0 mm is suitable. A thickness of about 3.0 mm to 6.0 mm, particularly preferably about 3.0 mm is suitable for a bare wire having a transmission voltage of 66 kV (voltage to ground of 38.1 kV).

The overlapping degree of the spirally wound insulating covers is preferably double. If the thickness of the insulating cover is selected so that sufficient insulation characteristics can be obtained by double winding, the mounting work is easy and the outer diameter does not become too large. However, the starting point and the ending point are tripled. It is preferable that the triple overlapped portion has a center angle of the bare wire of about 90 °.

Further, it is preferable that both side edges of the cover are tapered. As will be described later, when the insulating cover is attached to the bare wire, it is wound around the outer circumference of the bare wire in a spiral shape. Therefore, if both side edges are formed in a tapered shape, a step is unlikely to occur at the overlapping portion of the insulating cover, and it is possible to avoid the occurrence of a gap between the bare wire and the insulating cover, which deteriorates the insulating characteristics.

Particularly, when the both side edges of the cover are tapered, it is desirable that the both side edges have the same tapered shape.
When the insulating cover is attached to the bare wire, one side edge is a radially inner side (winding start) and the other side edge is a radially outer side (winding end). If the side edges have the same taper shape, it is not necessary to care about the winding direction of the insulating cover during winding, and the same mounting shape can be obtained regardless of which side edge is started.

Bare wires covered by the insulating cover of the present invention include jumper wires and main lines of power transmission lines. More specifically, ACSR, TACSR, GSTACSR, etc. can be mentioned. When the cover of the present invention is applied to the main line of the power transmission line, it is preferable to apply the cover to a place where the main line is close to trees or structures.

Further, the bare wire insulating structure of the present invention is characterized in that the outer circumference of the bare wire is spirally covered with the bare wire insulating cover. With this configuration, the outer circumference of the bare wire can be reliably covered with insulation, and a ground fault due to contact with birds, trees, etc. can be prevented.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a partial perspective view of the insulating cover of the present invention, and FIG. 2 is a sectional view showing a state in which a jumper wire is covered with the insulating cover of the present invention.

This insulating cover 10 is, as shown in FIG.
It is a long sheet, and the middle part 11 is formed by an arc (or plane) with a diameter slightly larger than the outer diameter of the jumper wire, and the side edges 12 have a winding tendency smaller than the outer diameter of the jumper wire. Are formed. Considering the wearability, this curl is not something that is wrapped in several turns,
It is preferable that the winding amount is less than 1.5 turns. More preferably, the winding amount is less than one round. An example of the bending diameter size of the curl on both sides is about 15 mmφ for an ACSR insulation cover of 18.2 mmφ.

The material of the insulating cover 10 is JIS K 6301 in order to obtain a restoring force that allows the insulating cover 10 to be spirally attached to the outer circumference of the jumper wire when the curl is opened.
Spring hardness test (A)
Silicone rubber having a rubber hardness of about 55 ° measured by a mold). Silicone rubber has excellent flexibility, can easily open the curl, and can be coated along a bent jumper wire. The thickness of the insulating cover 10 excluding the side edge portions 12 is set to about 3 mm so that the necessary withstand voltage characteristics can be obtained.

Both side edges 12 of the insulating cover are formed in the same tapered shape. This is because if both side edges are formed in a tapered shape, it is difficult for a step to occur in the overlapping portion of the insulating cover, and it is possible to avoid a gap between the jumper wire and the insulating cover 10 from deteriorating the insulating characteristic. This is because.

Table 1 shows the relationship among the types of typical jumper wires coated with the insulating cover of the present invention, the outer diameter, the cross-sectional area, and the width of the insulating cover. In Table 1, "SACSR" is a small-sized steel core stranded wire.

[0027]

[Table 1]

Such an insulating cover is used by being wound around the outer circumference of the jumper wire of the jumper device shown in FIG. Here, ACSR with aluminum wires twisted around the outer circumference of the steel core
Is used as a jumper wire. When winding, both edges 12
Then, the inner surface of the intermediate portion 11 is brought into contact with the jumper wire 1 and one side edge is wound around the outer circumference of the jumper wire. Furthermore, wrap the insulating cover 10 so that the other side edge covers one side edge, and insulate the entire circumference of the jumper wire.
Cover with 10. A cross-sectional view of the jumper wire after coating is shown in FIG.
As shown in, the outer circumference of the jumper wire 1 is covered with the insulating cover 10 in a spiral shape. Here, the insulating cover 10 is wound so as to be doubled. However, the start and end of the winding are wound in three layers.

Further, when a sample of a jumper wire having a length of 2 m was bent with a radius of 10 m, and the above-mentioned insulating cover was attached to the jumper wire, the jumper wire could be easily attached and the insulating cover was bent. It was installed along the jumper line.

With such an insulating cover, it is possible to easily attach / detach to / from the jumper wire, and it is possible to form the coating along the bent jumper wire. In addition, since the coating can be formed over the entire length of the long jumper wire with a single insulating cover, the effect of reducing the number of parts and improving the mounting workability is extremely large.

[0031]

As described above, according to the insulating cover and the insulating structure of the present invention, the following effects can be obtained.

The insulating cover of the present invention has a high insulating property,
And the workability is extremely good. The insulating cover of the present invention has excellent wearability and is unlikely to peel off due to climate, temperature, etc. It can be easily retrofitted to existing bare wires such as jumper wires. The diameter after construction can be much smaller than that of a conventional insulating cover, and an increase in wind pressure load can be reduced. It is possible to apply it continuously along the curved slack of the bare wire.

[Brief description of drawings]

FIG. 1 is a partial perspective view of an insulating cover of the present invention.

FIG. 2 is a sectional view showing a state in which a jumper wire is covered with an insulating cover of the present invention.

FIG. 3 is a sectional view of a conventional insulating cover.

FIG. 4 is an explanatory diagram of a state in which the insulating cover of FIG. 3 is attached to a jumper wire.

FIG. 5 is an explanatory diagram showing a state in which an overhead power transmission line including a jumper line is arranged in a steel tower.

[Explanation of symbols]

1 jumper wire 2 Retaining clamp 3 insulator 4 main lines 5 insulator 10 Insulation cover 11 Middle part 12 side edge 20 Insulation cover 21 ridges 22 joint cover 23 Tightening band 31 steel tower 32 arm material

Claims (6)

[Claims] 1. An insulating cover for covering the outer circumference of a bare wire, the insulating cover being in the form of a long sheet, and having a curl having a diameter smaller than the outer diameter of the bare wire on both side edges thereof. A bare wire insulation cover, which is made of an elastic material that provides a restoring force such that the insulation cover can be spirally attached to the outer circumference of the bare wire when the winding tendency is opened. 2. The cover has a value measured by a spring hardness test (A type) of JIS K 6301 “Vulcanized rubber physical test method” of 75 ° or less. Bare wire insulation cover. 3. The bare wire insulating cover according to claim 1, wherein the cover is made of at least one of fluororubber, silicone rubber, urethane rubber, ethylene propylene rubber, and chloroprene rubber. 4. The bare wire insulating cover according to claim 1, wherein both side edges of the cover are tapered. 5. The bare wire insulating cover according to claim 4, wherein the tapered shapes of the both side edges are the same. 6. An insulating structure for a bare wire, characterized in that the bare wire insulating cover according to claim 1 spirally covers the outer periphery of the bare wire.