JPH10262320A - Overhead power transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict an increase in slackness and prevent a great rolling of power transmission line by erecting a suspension wire between steel towers and by using a linear body having a negative linear expansion property as a suspension wire. SOLUTION: A suspension wire 10 is located above the power transmission line 20 and erected with a slackness smaller than the maximum slackness of the power transmission line 20, its both end portions are anchored to an anchoring steel tower 30 through an anchor insulator string 11, and the intermediate position of the power transmission line 20 in the longitudinal direction is suspended from the suspension wire 10 through a suspension spacer 50. As a suspension wire 10, invar steel stranded wire, carbonized silicon fiber, alumina fiber, aramid fiber having a negative linear expansion characteristics or other inorganic or organic fiber stranded to a rope form is used as a linear body. By doing this, the increase in slackness can be restricted and large rolling of the power transmission line 20 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for reducing sag,
The present invention relates to an overhead power transmission line in which lateral deflection is reduced.

[0002]

2. Description of the Related Art Conventionally, as described in Japanese Utility Model Application Laid-Open No. 57-102522, a suspension line having high mechanical strength such as a steel stranded wire is erected between steel towers 1 and a plurality of suspension lines are provided on the suspension line. 2. Description of the Related Art An overhead power transmission line in which a power transmission line is suspended via a spacer is known.

[0003]

However, in the overhead transmission line having the above configuration, the transmission line is hung on a suspension line having high mechanical strength such as a steel stranded wire, so that it is difficult to reduce the sag of the transmission line. For this reason, there is a problem that the lateral deflection of the transmission line cannot be suppressed. That is, since a suspension wire having a large mechanical strength such as a twisted steel wire generally has a positive linear expansion characteristic, the elongation increases as the temperature rises. For this,
In particular, when the outside air temperature rises in summer or the like, the sag of the suspension line itself increases, and accordingly the sag of the transmission line also increases, and it is difficult to reduce the sag of the transmission line after all. It will happen. If the sag of the transmission line is large, a problem arises in that the amount of rolling of the transmission line increases.

[0004]

SUMMARY OF THE INVENTION The present invention provides an overhead power transmission line which solves the above-mentioned problems, and has a construction in which a suspension line is provided between steel towers and a suspension spacer is provided on the suspension line. In an overhead power transmission line in which a transmission line is suspended via a wire, a linear body having a negative linear expansion characteristic is used as the suspension line (claim 1).

According to the first aspect of the present invention, the linear body having a negative linear expansion characteristic has an elastic modulus of 10,000 to 10,000.
It is characterized by being 30,000 kgf / mm ² (claim 2).

Further, in the invention according to claim 1 or 2, the suspension spacers are attached at substantially equal intervals of a transmission line installed between the steel towers, and the number of the suspension spacers is three or less. It is characterized by the following (claim 3).

When a linear body having a negative linear expansion characteristic is used as a suspension line, the linear body having a negative linear expansion characteristic becomes shorter in length as the temperature rises. , It is possible to suppress an increase in sag in summer or the like. For this reason, the lateral deflection of the transmission line can be reduced.

[0008] Further, as in the second aspect of the present invention, the linear body having a negative linear expansion characteristic has an elastic modulus of 10000.
Using what is ~30000kgf / mm ^2,
As described later, this is preferable because the increase in tension acting on the steel tower is small.

Further, as described in the third aspect of the present invention, when the suspending spacers are attached at substantially equal intervals of the transmission line installed between the steel towers and the number thereof is set to three or less, as described later, The number of hanging spacers used can be reduced to efficiently suppress the increase in sag.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of an overhead power transmission line according to the present invention, in which 10 is a suspension line, 20 is a transmission line, and 30 is a retaining tower. FIG. 1 shows only one line.

The suspension cable 10 is provided above the power transmission line 20 and the power transmission line 2.
It is installed lower than the maximum sag of 0, and both ends thereof are fixed to the retaining tower 30 via the retaining insulator string 11. A linear body having a negative linear expansion characteristic is used as the suspension wire 10, for example, a twisted invar steel wire, a silicon carbide fiber, an alumina fiber, an aramid fiber, or a wire formed by twisting other inorganic or organic fibers into a rope. A linear body obtained by twisting a composite body or a composite wire obtained by combining the above-mentioned fiber with a material such as aluminum or an aluminum alloy can be used.

The power transmission line 20 is retained by a retaining tower 30 via retaining insulator series 21 connected to both ends thereof. An intermediate position in the longitudinal direction of the transmission line 20 is suspended by the suspension line 10 via a suspension spacer 50. In the embodiment, the upper transmission line 20 is suspended from the suspension line 10 through two suspension spacers 50 at substantially equal intervals in the longitudinal direction, and the middle and lower transmission lines 20 are One intermediate position in the longitudinal direction is suspended from the suspension line 10 via the suspension spacer 50. The position where the transmission line 20 is suspended from the suspension line 10 is not particularly limited. However, as described later, it is preferable to attach the transmission line 20 to three or less locations at substantially equal intervals in the longitudinal direction of the transmission line.

In FIG. 1, reference numeral 60 denotes the retaining tower 3.
An overhead ground wire erected at the top of the zero
It is a jumper wire that electrically connects the transmission lines 20 at the positions.

As shown in FIG. 2, suspending spacers 50 are provided at both ends of a polymer insulator main body 51 at a transmission wire gripping bracket 52.
The armor rod 23 is wound around the suspension line 10 and the transmission line 20 at the position where the transmission line gripping bracket 52 is to be mounted to protect the suspension line 10 and the transmission line 20.

When the transmission line 20 is suspended from the suspension line 10 via the suspension spacer 50 as described above, the sag of the transmission line 20 can be reduced. Therefore, the transmission line 20
Can be reduced. For example, when there is no height difference between the towers, the roll amount when one center portion of the transmission line is hung with reference to FIG. 3 is calculated as follows. In FIG. 3, D1 is the sag before the transmission line is lifted, D2 is the sag after the transmission line is lifted, and it is assumed that D2 = 1 / 2D1. Θ is the lateral shake angle, L1 is the lateral shake amount at the time of the sag of D1, L2 is the lateral shake amount at the time of the sag of D2, and L0 is the lateral shake attenuation (L0 = L1−L2).
When the lateral vibration attenuation amount L0 is obtained, the result is as follows. L1 = D1 sin θ, L2 = D2 sin θ = １ ／ D1
Sin θ L0 = L1−L2 = １ ／ D1 sin θ Now, if θ = 60 °, since sin60 ° = 0.866, L0 = 0.43D1. Therefore, the lateral runout amount can be reduced by 43% as compared to before the suspension.

FIGS. 4 and 5 show a case where the present invention is applied to a suspension tower 35. The difference from the above-described embodiment is that a connection fitting 110 is inserted and connected to an intermediate portion of a suspension insulator series 100. The point is that the retaining insulator string 11 connected to the end of the suspension line 10 is connected to 110. In FIG. 5, reference numeral 115 denotes a suspension clamp, and 118 denotes an armor rod. The other points are the same as those of the above-described embodiment, and thus the same reference numerals are given and the description is omitted.

As described above, the connection fitting 110 is inserted and connected to the intermediate portion of the suspension insulator string 100, and the connection fitting 110 is
When the suspension insulator string 11 connected to the end of the suspension wire 10 is connected, when an unbalance load is applied to the suspension wire 10 located on the left and right of the suspension tower 35, the suspension insulator train 100 applies the unbalance load. It can be absorbed by flowing in the span direction. Therefore, the suspension tower 3
No harmful stress is applied to the suspension tower 35 as compared with the case where the hanging wire 10 is directly retained at 5. It is preferable that the connection fitting 110 inserted and connected to the intermediate portion of the suspension insulator series 100 be inserted and connected below the suspension insulator series 100 from the viewpoint of effectively utilizing the flow of the suspension insulator series 100 in the radial direction. .

(Embodiment) FIG. 6 shows how the sag reduction length of the transmission line changes depending on the hanging position when four types of linear bodies having negative linear expansion characteristics are used as the hanging lines. And how the tension applied to the retaining tower that holds the suspension line and the transmission line (meaning the tension of the suspension line and the transmission line) changes depending on the difference in the suspension position. It is a thing.

A 810 mm ² steel core aluminum stranded wire was used as a power transmission line, and the steel core aluminum stranded wire was laid over an anchoring tower having a distance of 300 m at an initial tension of 3000 kgf. Kepler (elastic coefficient 10,000 kgf / mm ² ), Invar steel wire (elastic coefficient 15400 kgf / mm ² ), PBO fiber (polyparaphenylene benzobisoxazole fiber) having negative linear expansion characteristics
(Elastic coefficient 28000 kgf / mm ² ) and carbon fiber (elastic coefficient 58800 kgf / mm ² ) were used to form a linear body having a cross-sectional area of 78.5 mm ² . This suspension line was erected on a retaining tower with an initial tension of 3000 kgf. Therefore, a total tension of 5000 kgf is acting on the retaining tower.

On the other hand, the position of the transmission line suspended by the suspension line is approximately one point at the center of the transmission line and divides the transmission line into approximately three equal parts.
Points, three points that divide the transmission line into approximately four equal parts, and 11 points that divide the transmission line into approximately twelve equal parts.

FIG. 6 shows the results, in which the horizontal axis represents the elastic modulus (kgf / mm ² ) and the vertical axis represents the sag (m).
And tension (kgf). B is the sag reduction length of the transmission line when one point is suspended substantially at the center of the transmission line, b is the sag reduction length of the transmission line when two points that divide the transmission line into approximately three equal parts, C is the sag reduction length of the transmission line when three points that divide the transmission line into approximately four equal parts, and d is the sag reduction length of the transmission line when the eleven points that divide the transmission line into approximately twelve equal parts are suspended. E is the tension applied to the anchoring tower when 11 points, which divide the transmission line into approximately 12 equal parts, are divided. The tension applied to the retaining tower when a point is hung and when three points that divide the transmission line into approximately four equal parts are shown, respectively.

From FIG. 6, it can be seen from FIG. 6 that the reduced length of the sag of the transmission line does not change much even if there are three or more suspension points, and that the tension applied to the tower support point does not change much even if the suspension point changes. It can be seen that, if the elastic modulus of the suspension line is increased, the sag of the transmission line is reduced, but the tension applied to the tower support point also increases. For example, when three points are hung using an Invar steel wire, the sag of the transmission line can be reduced by 74%, and the tension applied to the tower support point is 5000 kgf, which means that there is almost no change from the initial tension. . When three points are suspended using PBO fiber, the sag of the transmission line can be reduced by 58%, and the tension applied to the tower support point is 5500.
It turns out that it becomes about kgf.

As described above, the number of suspension spacers to be installed at substantially equal intervals of the transmission line installed between the towers is sufficient at three or less, so it is preferable that the number is not more than three. to reduce the sag of the wire may be increased elasticity coefficient of the suspension wire, but since it also increases the tension applied to the steel tower support points when the elastic modulus of the suspension wire is increased, the elastic modulus of the suspension wire is, 10000~30000kgf / mm ² Is preferably within the range.

In the above embodiment, the case where the present invention is applied to a single conductor having one transmission line has been described. However, the present invention has a plurality of transmission lines (for example, four). The present invention can be similarly applied to a multi-conductor power transmission line. The shape and the like of the suspension spacer used in the present invention are not particularly limited.

[0025]

As described above, the overhead transmission line according to the present invention is an overhead transmission line in which a suspension line is erected between steel towers and the transmission line is suspended on the suspension line via a suspension spacer. Since a linear body having a negative linear expansion characteristic is used as the suspension line, an increase in sag can be suppressed. Therefore, it is also possible to prevent a large lateral deflection of the transmission line.

The linear body having a negative linear expansion characteristic has an elastic modulus of 10,000 to 30,000 kgf / mm ^2.
By using the above, the increase in tension acting on the tower support point can be reduced.

Further, when the suspending spacers are installed at substantially equal intervals of the transmission line installed between the steel towers and the number of the suspending spacers is set to three or less, the number of the suspending spacers to be used is reduced and the suspending spacers are efficiently relaxed. The degree of increase can be suppressed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an overhead power transmission line according to the present invention.

FIG. 2 is a front view showing an embodiment of a hanging spacer used in the present invention.

FIG. 3 is an explanatory diagram showing a lateral runout of a transmission line.

FIG. 4 is a perspective view showing another embodiment of the present invention.

FIG. 5 is an enlarged front view of a main part of FIG. 4;

FIG. 6 shows a case where four types of linear bodies having negative linear expansion characteristics are used as suspension lines, and a change in a sag reduction length of a transmission line due to a difference in a suspension position and a retention due to a difference in a suspension position. The figure which shows the tension change added to a steel tower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Suspension line 20 Transmission line 30 Retention tower 35 Suspension tower 50 Suspension spacer 60 Overhead ground wire 70 Jumper wire 100 Suspension insulator

Claims (3)

[Claims] 1. An overhead transmission line in which a suspension line is erected between steel towers and a transmission line is suspended via a suspension spacer, a linear body having a negative linear expansion characteristic is provided as the suspension line. An overhead power transmission line, which is used. 2. The overhead transmission line according to claim 1, wherein the linear body having a negative linear expansion characteristic has an elastic modulus of 10,000 to 30,000 kgf / mm ² . 3. The suspension spacer according to claim 1, wherein the number of the suspension spacers is three or less, and the suspension spacers are attached at substantially equal intervals of a transmission line installed between the towers. The overhead transmission line described.