JP6003421B2 - Ground wire suspension system - Google Patents

Description

  The present invention relates to a ground wire suspending device that suspends a ground wire at the top of a steel pipe single column tower that supports the ground wire.

  Electricity generated at an electric power company's power plant is transmitted over a long distance through a transmission line that is stretched (supported) on a steel tower built on the ground. . The tower (transmission tower) that supports the transmission line may be hit by lightning. At this time, if the lightning strikes on the tower, the electric charge can be grounded, but if the transmission line is directly hit by lightning, there is a risk of causing a large-scale power outage due to disconnection of the transmission line or occurrence of abnormal current. is there.

  Therefore, the power transmission tower is provided with an overhead ground wire (also referred to as a ground wire, hereinafter simply referred to as a ground wire) for protecting the power transmission line from lightning. A ground wire is a conductive wire erected at the top of the transmission tower (above the transmission line) and receives lightning instead of the transmission line to prevent direct lightning strikes on the transmission line. A lightning surge caused by a lightning strike (abnormal high voltage caused by lightning) is conducted to the ground and discharged.

  The number of ground wires installed is either 1 or 2 depending on the relative positional relationship with the wire (determined by the angle at which the ground wire shields the lightning strike on the wire) so that the wire will not receive lightning strikes. Is done. When the number of ground wires is one, the ground wire is arranged at the top of the steel tower, which is approximately the center of the electric wires located on the left and right. In addition, when the number of ground lines is two, a brace is formed on the left and right as in the case of the electric wires, and the ground lines are arranged at positions where lightning strikes can be shielded.

  At this time, there are a case of using a tension device and a method of suspending the ground wire to the steel tower. Conventionally, when the number of ground wires is set to one, for example, a fixed suspension device as shown in FIG. 4 of Patent Document 1 or a tension device as shown in FIGS. 5 and 6 is used. . Further, when the number of ground wires is two, a free center type suspension device as shown in FIG. 8 of Patent Document 2 and a tension device similar to FIGS. 5 and 6 of Patent Document 1 are used. .

  By the way, the steel tower includes a square steel tower composed of four main pillar materials and a steel pipe single pillar steel tower composed of one main pillar material by connecting a steel pipe by a flange or welding. In the prior art, when the number of ground wires installed in a steel pipe single-column tower is one, a fixed suspension device or tension device as shown in FIG. 4 of Patent Document 1 is used.

JP 2007-267475 A JP 2009-278893 A

  Here, the steel pipe single column tower is superior to the square tower from the viewpoint of landscape and economy, but it is more likely to shake when the earthquake motion is applied compared to the square tower. It tends to occur. For this reason, in steel pipe single-column towers, due to the large vibration (displacement) of the tower at the time of the earthquake, the ground wire restrained at the top of the tower by a fixed suspension clamp or tension device is displaced by the vibration of the tower and tension Increase or decrease. For this reason, the vibration amplitude of the ground wire between the front and rear steel towers increases with time, and the possibility that the ground wire comes into contact with the power transmission line and causes an electrical accident is greater than that of the square steel tower.

  Due to the above circumstances, when holding a ground wire in a steel pipe single pillar steel tower, a free center type support device that hardly transmits vibration from the steel tower is used like a suspension system when the number of ground wires is two. It is hoped that. However, the top of the steel pipe single-column tower is configured as shown in FIG. 4, and there is no mounting surface on which a free center type suspension device can be installed. Therefore, it was difficult to apply the free center type suspension clamp to the steel pipe single column tower.

  In view of such a problem, the present invention can reduce the vibration amplitude of the ground wire by making it possible to attach a free center type suspension clamp to a steel pipe single column tower, and improve the seismic isolation effect. An object of the present invention is to provide a ground suspension device that can be designed.

In order to solve the above problems, a typical configuration of a ground wire suspension device according to the present invention is a ground wire suspension device that suspends a ground wire at the top of a steel pipe single column tower that supports the ground wire. attached to the top of the column tower, comprising a frame body ground wire therein is inserted, is attached to the frame body, and a suspension clamp of the free center type for suspending the earth line in the frame body, the frame includes a plurality Are formed by joining the angle members of, and have a triangular truss structure in a side view in the line direction of the ground wire, the free center type suspension clamp is fixed to the upper portion of the frame body, A holding portion that holds a ground wire, and a link portion that connects the fixing portion and the holding portion so that the holding portion can swing in a horizontal direction perpendicular to the track direction and the track direction of the ground wire. To do.

  According to the said structure, a free center type suspension clamp can be attached to the top part of a steel pipe single pillar steel tower (henceforth only a steel tower) via a frame, and it becomes possible to suspend a ground wire. . And since the holding part of the free center type suspension clamp attached to the top of the tower can swing in the horizontal direction perpendicular to the line direction of the ground line and the line direction by the link part, it absorbs the vibration of the tower Can do. Thereby, transmission of the vibration to the ground line is suppressed, and the vibration amplitude of the ground line is reduced. By suspending the ground wire in the steel tower in this way, it functions as a seismic isolation mechanism, so the vibration amplitude of the ground wire accompanying the vibration of the steel tower can be greatly reduced, and the seismic isolation effect can be improved. It becomes possible.

The height from the fixed part to the holding part is preferably 50 cm or more. With this configuration, the vibration amplitude can be most preferably reduced, and a higher seismic isolation effect can be obtained. The frame has a truss structure . Thereby, high rigidity can be obtained in the frame.

  According to the present invention, by allowing a free center type suspension clamp to be attached to a steel pipe single column tower, it is possible to reduce the vibration amplitude of the ground wire and to improve the seismic isolation effect. A ground suspension device can be provided.

It is a whole perspective view of the ground wire suspension apparatus concerning this embodiment. It is a figure explaining rocking | fluctuation of a free center type suspension clamp. It is a figure explaining the vibration suppression effect of the ground wire by the free center type suspension apparatus of this embodiment. It is a figure explaining the retention of the ground wire using the tension plate in a steel pipe single pillar steel tower.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  FIG. 1 is an overall perspective view of a ground wire suspension apparatus according to the present embodiment. As shown in FIG. 1, the ground wire suspension device (hereinafter referred to as a suspension device 100) according to the present embodiment is mainly composed of a frame body 110 and a free center type suspension clamp 120, and is a steel pipe single column tower. The ground wire 40 supported by the steel tower 10 is suspended from the top 10a of the steel tower 10 that is.

  The frame 110 is attached to the top part of the steel tower 10, and the ground wire 40 is inserted in the inside. The frame body 110 is formed by joining a plurality of angle members 112a, 112b, 112c, 112d, 112e, 112f, and 112g. In the present embodiment, the plurality of angle members 112a to 112g are joined by bolts and nuts, but this is only an example, and the plurality of angle members 112a to 112g can be joined by other methods such as welding. It is.

  In the present embodiment, the frame body 110 has a truss structure (triangular shape) in a side view of the ground line 40 in the line direction. Thereby, high rigidity can be obtained in the frame 110, and deformation of the frame 110 can be suppressed. The shape of the frame 110 is not limited to this, and may be other shapes such as a quadrangle.

  In the frame 110, lower angle members 112b and 112c are attached to the top 10a of the tower 10, and a free center type suspension clamp 120 for hanging the ground wire 40 is attached to the upper angle member 112a. Thereby, it becomes possible to attach the free center type suspension clamp to the top portion 10 a of the steel tower 10 through the frame 110. In this embodiment, the lower angle members 112b and 112c are attached to the top 10a of the tower 10 and the free center type suspension clamp 120 is attached to the upper angle member 112a. Although illustrated, this is only an example, and it may be attached by other methods.

  The free center type suspension clamp 120 is attached to the frame body 110 and suspends the ground wire 40 in the frame body 110. Specifically, the free center type suspension clamp 120 includes a fixing portion 122 fixed to the upper portion of the frame 110, a holding portion 124 that holds the ground wire 40, and a link portion 126 that connects them.

  FIG. 2 is a diagram for explaining the swing of the free center type suspension clamp 120. FIG. 2A is a diagram of the suspension device 100 observed from the line direction of the ground line 40, and FIG. It is the figure which observed the suspension apparatus 100 from the same angle as FIG. The link part 126 described above connects the fixing part 122 and the holding part 124 so as to be swingable in the line direction of the ground line 40 and a horizontal direction orthogonal to the line direction (hereinafter referred to as an orthogonal horizontal direction).

  In this embodiment, the link part 126 is comprised by the 1st movable part 126a, the 2nd movable part 126b, and the connection part 126c. The first movable portion 126 a is connected to the fixed portion 122 so as to be swingable in the horizontal direction orthogonal to the ground line 40. Thereby, as shown to Fig.2 (a), the holding | maintenance part 124 can rock | fluctuate in the orthogonal horizontal direction of the ground line 40 (refer FIG. 1).

  The second movable portion 126b is connected to the first movable portion 126a so as to be swingable in the line direction of the ground line 40. The holding portion 124 is connected to the second movable portion 126b through the connection portion 126c. Thereby, as shown in FIG.2 (b), the holding | maintenance part 124 can rock | fluctuate in the track | line direction of the ground wire 40 (refer FIG. 1). In the present embodiment, the second movable portion 126b and the holding portion 124 are connected via the connection portion 126c. However, the present invention is not limited to this, and the second movable portion 126b and the holding portion 124 are directly connected. May be.

  The height from the fixing part 122 to the holding part 124 described above is preferably 50 cm or more (0.5 m or more). FIG. 3 is a diagram for explaining the effect of suppressing ground vibrations by the suspension device 100 of the present embodiment. FIG. 3 shows the simulation analysis result of the maximum amplitude of the ground line when the measured acceleration waveform of the earthquake is given using the nonlinear dynamic structure analysis program. The analysis model consisted of steel towers and ground wires between 3 groups and 4 diameters. The vertical axis shows the maximum amplitude at the center of the span of the ground wire (the midpoint between the steel towers). The horizontal axis changes the height from the fixing portion 122 to the holding portion 124 (hereinafter referred to as a suspension clamp length).

  As shown in FIG. 3, the maximum amplitude of the ground line 40 decreases as the suspension clamp length increases. When the suspension clamp length exceeds 0.5 m, the maximum amplitude of the ground line 40 increases in the orthogonal horizontal direction. About 76% is suppressed by about 85% in the vertical direction (orthogonal vertical direction) orthogonal to the line direction. Moreover, when the suspension clamp length exceeds 50 cm, the suppression effect is hardly improved. From this, it can be understood that the vibration amplitude of the ground wire 40 at the time of vibration of the steel tower 10 can be most preferably reduced by setting the suspension clamp length to 50 cm or more.

  In addition, since the vibration suppression effect of the ground wire 40 changes depending on factors such as the distance between the steel towers 10 on which the ground wire 40 is supported, it is preferable to appropriately adjust the suspension clamp length according to the situation. In the suspension device 100 of the present embodiment, the link portion 126 is configured by the first movable portion 126a, the second movable portion 126b, and the connection portion 126c. Therefore, if the connection portion 126c is replaced, the suspension clamp length can be easily adjusted. Is possible.

  As described above, according to the suspension device 100 of the present embodiment, the ground wire 40 can be suspended at the top portion 10a of the steel pipe single-column tower (steel tower 10) by the frame 110 and the free center type suspension clamp 120. It becomes. The link portion 126 allows the holding portion 124 (free center type suspension clamp 120) to swing in the line direction of the ground line 40 and the direct horizontal direction, so that the vibration of the steel tower 10 can be absorbed. Transmission of vibration to the line 40 is suppressed. Thereby, the vibration amplitude of the ground wire 40 accompanying the vibration of the steel tower 10 can be greatly reduced, and the seismic isolation effect can be improved.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  INDUSTRIAL APPLICATION This invention can be utilized for the ground wire suspension apparatus which suspends this ground wire in the top part of the steel pipe single pillar steel tower which supports a ground wire.

DESCRIPTION OF SYMBOLS 10 ... Steel tower, 10a ... Top part, 20a ... Tensile plate, 20b ... Tensile plate, 30a ... Tensile clamp, 30b ... Tensile clamp, 40 ... Ground wire, 50 ... Jumper clamp, 100 ... Suspension device, 110 ... Frame 112a ... Angle material, 112g ... Angle material, 120 ... Free center suspension clamp, 122 ... Fixed part, 124 ... Holding part, 126 ... Link part, 126a ... First movable part, 126b ... Second movable part, 126c ... connection part

Claims (2)

A ground wire suspending device for suspending the ground wire at the top of a steel pipe single pillar tower supporting the ground wire,
A frame that is attached to the top of the steel pipe single-column tower and into which the ground wire is inserted;
A free center type suspension clamp attached to the frame body and suspending the ground wire in the frame body;
With
The frame body is formed by joining a plurality of angle members, and has a triangular truss structure in a side view in the line direction of the ground wire,
The free center suspension clamp is
A fixing portion fixed to an upper portion of the frame,
A holding unit for holding the ground wire;
A link portion that connects the fixing portion and the holding portion so that the holding portion can swing in a horizontal direction perpendicular to the line direction of the ground line and the line direction;
A ground wire suspension device characterized by comprising:   The ground wire suspension apparatus according to claim 1, wherein a height from the fixing portion to the holding portion is 50 cm or more.

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