JPH1189060A - Gas-insulated transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sufficiently earthquake-resistant construction, by deviating the intermediate portion of a sheath from the straight line connecting adjacent bases perpendicularly to a horizontal axis, and controlling the amount of the deviation to a specified ratio to the distance between the adjacent main bases. SOLUTION: When the ratio of deviation is reduced, the distance between main bases 12 required for ensuring earthquake resistance is reduced. As a result, when increase in cost resulting from the adoption of the bent structure is compared with reduction in cost resulting form the simplification of part of the bases and foundations, the superiority of the bent structure may be deteriorated, and a lower limit of 5% or so is appropriate. When the ratio of deviation is increased, the area of the site required for the installation of gas- insulated transmission lines is increased, and the cost efficiency is degraded. If the ratio of deviation exceeds 15%, the number of vibrations of primary bending moment and secondary bending moment starts to gradually decrease, and 15% is appropriate, accordingly. When the sheath 11 receives force in the x and y directions in the position of the elastic base 14 as well, the elastic base 14 is displaced. Therefore, a moment produced in the foundation 15b is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas insulated power transmission line, and more particularly to an improvement in its seismic structure.

[0002]

2. Description of the Related Art Conventionally, transmission lines for transporting electric power include:
Some of them were by overhead wires or cables, but recently gas-insulated transmission lines have been put into practical use. The gas insulated transmission line is one in which an electric conductor is arranged at the center of a metal sheath filled with SF ₆ gas. The gas-insulated transmission line having such a structure is long and supported by a gantry installed at regular intervals.

FIG. 14 is a block diagram showing a conventional gas-insulated transmission line shown in, for example, "Seismic resistance characteristics of long-distance gas-insulated transmission line" on pages 7-233 of the 1995 IEEJ National Convention. FIG. 14 shows a section of 56 m of the gas-insulated transmission line having a total length of several km, and such a structure is repeatedly connected.

In FIG. 1, reference numeral 1 denotes a metal sheath filled with SF ₆ gas, 2 denotes an electric conductor arranged at the center of the sheath 1, and 3 to 5 denote the electric conductor 2 by the sheath 1.
Are a fixed tripod spacer, a movable tripod spacer, and a conical spacer, respectively. 6 is a bellows arranged between the adjacent sheaths 1.

[0005] Reference numeral 7 denotes a plurality of mounts 7 fixed on a large-sized concrete foundation and supporting the sheath 1, and eight of these mounts 7 are provided at intervals of 7 m in a section of 56 m. The gantry 7 includes a fixed gantry 7a and a movable gantry 7b.
There is. Here, the axial direction of the sheath 1 in FIG.
When the vertical direction is defined as the Z axis and the direction perpendicular to the XZ plane (the direction perpendicular to the horizontal axis) is defined as the Y axis, the fixed gantry 2a has a rigid support structure that restrains the displacement and rotation of the sheath 1 in all directions. ing. On the other hand, the movable gantry 2b has a support structure that restricts displacement in the Z and Y directions and allows displacement in the X direction.

In such a gas-insulated power transmission line, when its length changes due to a change in load current during use or a change in ambient temperature due to a change in ambient temperature, it moves in the X direction on the movable gantry 7b in accordance with the expansion and contraction. The thermal expansion and contraction in the 56 m section sandwiched between the fixed gantry 2 a is absorbed by the bellows 6.

Here, the seismic design of gas-insulated transmission lines is generally performed as follows. First, regarding the input direction of a seismic wave, the Y direction is the strictest condition in terms of seismic performance. When vibrated in the Y direction, each pedestal 7 can be treated as if the weight of the sheath 1 and its internal components was loaded on the beam structure supported by the foundation. Therefore, during an earthquake, a bending moment around the X-axis determined by the mass distribution and the acceleration distribution of the gantry 7, the sheath 1, and its internal components is generated in the gantry 7, and reaches the maximum moment at the fixed end of the gantry 7.

On the other hand, since the sheath 1 has a beam structure in which both ends are supported by the gantry 7, during an earthquake, Z determined by the mass distribution and acceleration distribution of the sheath 1 and its internal components.
A bending moment about the axis is generated in the sheath 1. Especially,
When the natural frequency of the gas insulated transmission line coincides with the frequency component of the seismic wave and resonates, the amplitude is amplified and their bending moments are further increased.

[0009] The seismic force in the X direction can be handled as a ramen structure with the sheath 1 and the gantry 7.
The seismic performance is higher than the direction. Also, the seismic force in the Z direction is generally considered to be about half or less of the X direction or the Y direction.

With respect to seismic force in the Y direction, the following seismic design is made. That is, with respect to the bending moment around the Z-axis generated in the sheath 1, the diameter, the plate thickness, and the material of the sheath 1 are selected so as to secure the necessary strength, and the gantry for restraining the displacement in the Y direction. Seven intervals are determined. In this case, the bending moment around the Z-axis generated in the sheath 1 becomes smaller as the gantry interval is smaller.

[0011] In addition, the required strength of each of the pedestals 7 with respect to the generated bending moment around the X-axis is ensured.
Furthermore, since the above bending moment is maximized at the lower end of the gantry 7, it is necessary to consider the bonding strength between the lower end of the gantry 7 and the foundation, and the design of the strength of the connecting members such as anchor bolts used for this connecting portion is also performed. Will be Furthermore, the size and structure of the foundation are examined to have a sufficient supporting force against the inertial force generated by the weight of the gas insulated transmission line.

[0012] In the seismic design, a dynamic design is performed in consideration of the deformation due to the resonance of the structure when a seismic wave is input.
Generally, the seismic wave has a predominant frequency range of 0 to 10 Hz, and the higher the natural frequency, the smaller the displacement. Therefore, the seismic performance can often be ensured by setting the natural frequency of the device to about 10 Hz or more. In order to increase the natural frequency of the gas-insulated transmission line, there are a method of increasing the bending stiffness of the sheath 1 and the gantry 7, a method of reducing the interval between the gantry, and a method of enlarging the foundation.

[0013]

In the conventional gas insulated transmission line constructed as described above, the strength and rigidity of the sheath 1 and the gantry 7 are increased and the interval between the gantry is reduced in order to secure the seismic performance. In addition, it is necessary to install a large foundation capable of supporting these bases 7 sufficiently,
The whole is large and the cost is high.

At places where gas insulated transmission lines cross rivers and wide roads, or where other structures become obstacles, the spacing between the stands becomes large, or the stand 7 has a predetermined strength and rigidity. And it becomes impossible to install a foundation, and it becomes difficult to secure sufficient seismic performance.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has a simple structure of a base and a part of a base while securing earthquake resistance.
It is an object of the present invention to provide a gas-insulated transmission line that can reduce costs and can secure a sufficient supporting structure of an earthquake-resistant structure even in a place where a stand is difficult to install.

[0016]

According to a first aspect of the present invention, there is provided a gas insulated power transmission line, wherein a sheath filled with an insulating gas and an electric conductor disposed in the sheath are spaced apart from each other. And a plurality of main frames that support the sheath so as to restrain the displacement in the vertical direction and the direction perpendicular to the horizontal axis, and between the adjacent main frames to restrain the displacement in the vertical direction and maintain the axial and horizontal directions. An intermediate frame that supports an intermediate portion of the sheath between adjacent main frames so as to allow displacement in a direction perpendicular to the axis, wherein the intermediate portion of the sheath extends in a direction perpendicular to a horizontal axis with respect to a straight line connecting the adjacent frames. And the amount of eccentricity of the intermediate portion from the straight line is 5% of the distance between the adjacent main frames.
% To 15%.

The gas insulated transmission line according to the invention of claim 2 is
The eccentricity is caused by bending the middle part of the sheath.

The gas-insulated transmission line according to the invention of claim 3 is:
A plurality of linear sheaths are connected to each other in a bent state, and the center in the longitudinal direction of each sheath is supported by a main frame,
The bent connecting portion is supported by an intermediate mount.

The gas-insulated transmission line according to the invention of claim 4 is:
The middle part of the sheath is eccentrically bent in an arc shape.

The gas insulated transmission line according to the invention of claim 5 is:
An elastic mount having an elastic column elastically deformable in the axial direction of the sheath and in the direction perpendicular to the horizontal axis is used as an intermediate mount.

The gas insulated transmission line according to the invention of claim 6 is:
A horizontal moving base having a pedestal and a sheath supporting member slidably provided on the pedestal in an axial direction and a direction perpendicular to the horizontal axis and to which a sheath is fixed is used as an intermediate mount.

The gas insulated transmission line according to the invention of claim 7 is:
A low friction sheet member made of a material having a low coefficient of friction is attached to a sliding surface between the pedestal and the sheath support member.

The gas insulated transmission line according to the invention of claim 8 is:
A suspension having a pedestal fixed to a support structure disposed above the sheath, a sheath support member to which the sheath is fixed, and a link rotatably connected between the pedestal and the sheath support member. The gantry was used as an intermediate gantry.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a plan view showing a part of a gas-insulated transmission line according to Embodiment 1 of the present invention, FIG. 2 is a side view of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG.
An axis, a Y axis and a Z axis are defined as shown in each figure.

In the figure, reference numeral 11 denotes a metal sheath filled with, for example, SF ₆ gas as an insulating gas, and an electric conductor 2 is disposed in the center of the sheath 11. Reference numeral 12 denotes a plurality of main gantry for supporting the sheath 11. These main gantry 12 correspond to the fixed gantry 7a or the movable gantry 7b shown in FIG. 14 as a conventional example, and have at least the Y direction (horizontal axis perpendicular direction) and The displacement in the Z direction (vertical direction) is restricted.

The sheath 11 has a plane shape in the shape of a "<" which is bent at a position substantially equal to each of the two main frames 7 adjacent to each other. Are decentered by a from the straight line connecting. If the ratio of the amount of eccentricity a to the distance between two adjacent main frames 7 is defined as the eccentricity, the eccentricity in this example is 5%.

Reference numeral 13 denotes a flange for connecting the sheath 1 at the bent portion. The flange surface of the flange 13 is inclined at an angle θ with respect to the axis of the sheath 2 corresponding to the bent shape of the sheath 1. Reference numeral 14 denotes an elastic gantry serving as an intermediate gantry for supporting a bent intermediate portion of the sheath 1. The elastic gantry 14 has a flexible structure capable of restricting displacement in the Z direction and moving in the X and Y directions. 15a and 15b are foundations for fixing the main gantry 12 and the elastic gantry 14, respectively.
The base 15b is smaller than the base 15a.

As shown in FIG. 3, the elastic base 14 includes an elastic column 16 having a low bending rigidity, a sheath supporting member 17 provided on the elastic column 16 for receiving the sheath 11, and a sheath supporting member 17 Band fitting 1 to be fixed to
Eight. FIG. 4 is a plan view showing a state where a plurality of the gas-insulated transmission lines of FIG. 1 are connected.

Next, the effect on the seismic performance of the gas insulated transmission line will be described using the results obtained from the finite element analysis. First, FIG. 5 shows an analytical model of a gas-insulated transmission line having no bent structure using beam elements. Both ends of the model are displaced and constrained in all directions assuming a fixed base. 6 and 7 show vibration modes of the gas-insulated transmission line as analysis results. The broken line in FIG. 6 is a modified view of the primary bending mode, and the broken line in FIG. 7 is a modified view of the secondary bending mode. Is shown.

For example, taking the conventional gas insulated transmission line as an example, the vibration frequency in the vibration mode is obtained.
, The primary bending mode is 9.4H
z, the secondary bending mode is 37.6 Hz. This gas insulated transmission line has a minimum natural frequency of 9.4 Hz at 10 Hz.
Therefore, it is considered that the structure satisfies the seismic performance. On the other hand, when the same gas-insulated transmission line is set to 20 m only for the distance between the gantry, the primary bending mode is 2.4H
z, the secondary bending mode is 9.4 Hz, and when the minimum value of the natural frequency is 2.4 Hz, it is considered that the seismic performance is clearly insufficient.

Next, the seismic performance of a gas-insulated transmission line having a bent structure as shown in FIG. 1 will be considered. FIG. 8 shows FIG.
FIG. 3 is an explanatory diagram showing an analysis model of the gas insulated transmission line of FIG. 1, in which a distance between both ends is 20 m, and both ends are displaced and restrained in all directions assuming a main gantry 12. The sheath 11 is bent at a position 10 m from one end with an eccentricity of 5%. The elastic gantry 14 is installed at the bending point of the sheath 11, but in the analysis model, assuming that the bending stiffness of the elastic gantry 14 is small, the bending point is restricted only in the Z direction and free in the Y and X directions. .

The natural frequency at this time is 7.7 Hz in the primary bending mode and 9.3 Hz in the secondary bending mode. This minimum natural frequency of 7.7 Hz is almost three times the minimum natural frequency of 2.4 Hz when a 20 m linear sheath is used, and the seismic performance is greatly improved by using a bent structure with an eccentricity of 5%. Moreover, considering the effect of the rigidity of the elastic gantry 14 at the bending point, the natural frequency is expected to be higher than 7.7 Hz. In addition, if the minimum natural frequency is 9.4 Hz, which is the same as that of the conventional design with a stand spacing of 10 m,
At an eccentricity of 5%, the distance between the main frames 12 can be reduced from 20 m to 17 m.

Next, the operation of the elastic base 14 will be described. When the sheath 11 is displaced in the X direction due to thermal expansion and contraction, each elastic base 14 is easily elasticized at the elastic column 16 so that the amount of thermal expansion and contraction of the sheath 11 is transmitted to the bellows (not shown) installed coaxially. Bending deformation. Further, by increasing the solid frequency by making the sheath 11 a bent structure, the displacement in the Y direction due to the seismic force is reduced, but if the displacement in the Y direction occurs, the elastic column 16 is easily elastically bent and deformed.

As described above, even when the sheath 11 receives a force in the X direction and the Y direction at the position of the elastic
Is easily deformed, the moment generated in the elastic gantry 14 and the foundation 15b is reduced. Therefore, the elastic base 14
The joint between the base and the base 15b and the base 15b can be simplified and reduced in size. Here, the elastic gantry 14 receives the own weight of the gas insulated transmission line and the vertical load at the time of the earthquake, but the vertical load is not a severe load condition compared with the bending moment generated in the conventional gantry having a rigid structure.

Next, the applicable range of the eccentricity will be described based on the relationship between the eccentricity and the seismic performance. FIG. 9 is a graph showing the relationship between the eccentricity and the natural frequency when the distance between the main frames 12 is 20 m. In the figure, the minimum natural frequency is
From the eccentricity of 0% to the intersection of the curve of the primary bending mode and the curve of the secondary bending mode, the frequency becomes the primary bending mode,
Beyond the intersection, the frequency becomes the secondary bending mode frequency. Judging from the minimum natural frequency, this intersection becomes the optimum eccentricity.
However, if the structure of the gas insulated transmission line changes, the relationship between the eccentricity and the frequencies of the primary bending mode and the secondary bending mode is expected to slightly change, so it is necessary to consider the adjustment width.

Regarding the lower limit of the eccentricity, when the eccentricity is reduced, the interval between the main gantry 12 necessary for securing the seismic performance is reduced, and the increased cost due to the bent structure of the sheath 11 and the gantry and base It is conceivable that the superiority of the bent structure is lost in comparison with the cost reduction by simplifying a part of the bending structure. Therefore, it is considered that a lower limit of about 5% is appropriate.

As for the upper limit of the eccentricity, if the eccentricity is large, the site required for arranging the gas insulated transmission line becomes large and the economic efficiency is reduced. Judging from the fact that the frequencies of the mode and the secondary bending mode start to decrease gradually, it is considered that the upper limit is 15%.

As described above, when the bent structure with the eccentricity of 5% to 15% is used, instead of the conventional base and the large foundation capable of restraining the displacement in the Y direction while securing the predetermined seismic performance, The elastic base 14 having a simple structure and the small base 15b can be installed at the bent portion of the sheath 11, and the cost can be reduced.

In order to obtain the optimum values of the eccentricity and the gantry spacing in the actual design, it is sufficient to use the finite element method analysis. In addition, as for the structure when the sheath 11 of FIG. 1 is repeatedly connected, the main gantry 12 is arranged around the center of the linear sheath 11 as shown in FIG. In this case, the arrangement of the gas insulated transmission line is simplified, and the number of bent portions of the sheath 11 can be reduced.

Embodiment 2 Next, FIG. 10 is a plan view showing a part of a gas-insulated transmission line according to Embodiment 2 of the present invention, and FIG. 11 is a sectional view taken along the line XI-XI of FIG. In the figure, reference numeral 21 denotes a metal sheath in which SF ₆ gas is filled, and an electric conductor 2 is disposed in the center of the sheath 21. Further, the sheath 21 is provided by a main frame 12 that restricts displacement in at least the Y direction (horizontal axis perpendicular direction) and a Z direction (vertical direction), and a horizontal moving frame 22 as an intermediate frame that restricts only displacement in the Z direction. Supported. Further, the sheath 21 has a shape drawing an arc, and is decentered by a from a straight line connecting the two main frames 12.

The horizontal moving base 22 includes a pedestal 23,
A sheath support member 24 is provided on the pedestal 23 so as to be displaceable in the X and Y directions and receives the sheath 11, and a band metal fitting 25 for fixing the sheath 21 to the sheath support member 24 is provided. Further, a low friction sheet member 26 made of a material such as Teflon is provided at an engagement portion of the upper end of the pedestal 23 with the sheath support member 24. Further, gaps b are provided between the pedestal 23 and the sheath support member 24 so that the sheath 21 can move in the Y direction.

Next, the effect on the seismic performance of the gas insulated transmission line will be described using the results obtained from the finite element analysis. In a conventional gas insulated transmission line, when the condition of the distance between the gantry is 20 m, the primary bending mode is 2.4 Hz,
The next bending mode became 9.4 Hz. In the arc structure shown in FIG. 10, the distance between two adjacent main mounts 12 is 20 m.
Assuming that the eccentricity is 5%, the natural frequency is 9.4 Hz in the primary bending mode and 8.4 Hz in the secondary bending mode. Thus, by making the linear structure into an arc structure, the minimum natural frequency increases from 2.4 Hz to 8.4 Hz.

Therefore, when a circular arc-shaped euploid structure such as the sheath 21 is employed, a conventional gantry and a large-sized base capable of restraining displacement in the Y-direction while securing a predetermined seismic resistance performance as in the first embodiment. Instead of the foundation, the horizontal moving base 22 having a simple structure and the small foundation 15b can be installed on the curved portion of the sheath, so that the cost can be reduced.

Next, the operation of the horizontal plane mount 22 will be described. When the sheath 21 is displaced in the X direction due to thermal expansion and contraction, the portion of the low friction sheet member 26 of the pedestal 23 slides,
This displacement is absorbed. Further, the displacement in the Y direction due to the seismic force is small because the sheath 21 has an arc shape, and even if displacement in the Y direction occurs, a gap b is formed between the sheath support member 24 and the pedestal 23. Since it is provided, the portion of the low friction sheet member 26 of the pedestal 23 slides, and this displacement is absorbed. Therefore, the horizontal force transmitted to the pedestal 23 by the displacement of the sheath 21 is reduced.

For this reason, the load applied to the horizontal moving base 22 is only the vertical load, and the horizontal load and moment are reduced.
And the base 15b can be simplified and downsized.

The elastic gantry 14 of the first embodiment may be used in place of the horizontal moving gantry 22 of the second embodiment. Conversely, the horizontal mount 22 of the second embodiment may be used instead of the elastic mount 14 of the first embodiment.

Embodiment 3 Next, FIG. 12 is a perspective view showing a part of a gas-insulated power transmission line according to Embodiment 3 of the present invention. In the figure, 31 is an iron beam as a support structure disposed above the sheath 11, and 32 is a suspension frame as an intermediate frame provided at an intermediate portion of the iron beam 31 and suspending the sheath 11. And the sheath 11 according to the first embodiment.
It has a bending structure similar to that described above.

FIG. 13 is a side view showing the suspension stand 32 of FIG. The suspension base 32 includes a pedestal 33 fixed to the steel beam 31 and a link 3 connected to the pedestal 33.
4. A sheath support member 35 to which the sheath 11 is fixed, a pin 36 for rotatably connecting the link 34 to the pedestal 33 and the sheath support member 35, and a band fitting 37 for fixing the sheath 11 to the sheath support member 35. Have.

In such a support structure, the sheath 11 is supported by the steel beams 31 when a required gantry space cannot be secured at a place where the gas insulated transmission line crosses a river or a wide road. In such a structure, since the same bending structure as that of the first embodiment is employed, the seismic performance of the sheath 11 is high.

The operation of the suspension gantry 32 is as follows. When the sheath 11 is displaced in the X direction due to thermal expansion and contraction, these loads are not transmitted to the steel beam 31 because the sheath 11 can be easily moved by the link 34 of the suspension base 32. Further, since the sheath 11 has a bent structure, the displacement in the Y direction due to the seismic force is small enough to be absorbed by the elastic bending and rattling of the link 34.

Further, when the sheath 11 has a bent structure,
As in the first embodiment, the natural frequency of the primary bending of the sheath 11 in the Y direction is increased, so that the bending rigidity of the steel beam 31 in the horizontal direction can be reduced, and the structure of the steel beam 31 can be reduced. This can be simplified and cost can be reduced.

[0052]

As described above, in the gas insulated transmission line according to the first aspect of the present invention, the middle portion of the sheath is decentered by 5% to 15% with respect to the interval between the adjacent main frames, and the sheath is vertically extended. The eccentric middle part of the sheath is supported by the intermediate gantry that restrains only the displacement, so that the gantry and a part of the gantry can be made a simple structure and the cost can be reduced while securing the earthquake resistance. .

In the gas insulated transmission line according to the second aspect of the present invention, the middle portion of the sheath is bent and eccentric, so that the middle portion of the sheath can be eccentric with a simple structure, thereby increasing the cost due to the eccentricity. Can be suppressed.

In the gas insulated transmission line according to the third aspect of the present invention, a plurality of linear sheaths are connected to each other in a bent state, the center of each sheath in the longitudinal direction is supported by a main frame, and the bent connecting portion is provided. Is supported by the intermediate mount, so that the entire arrangement is simplified and the number of bent portions of the sheath can be reduced.

In the gas insulated transmission line according to the fourth aspect of the present invention, the middle portion of the sheath is eccentrically bent in an arc shape, so that the seismic performance can be further improved.

In the gas insulated transmission line according to the fifth aspect of the present invention, since the elastic mount having the elastic column capable of being elastically deformed in the axial direction of the sheath and in the direction perpendicular to the horizontal axis is used as the intermediate mount, the intermediate structure of the sheath can be realized with a simple structure. The displacement of the part can be easily absorbed.

According to a sixth aspect of the present invention, there is provided a gas-insulated transmission line, comprising: a pedestal; and a horizontally movable pedestal having a sheath supporting member provided on the pedestal so as to be slidable in an axial direction and a direction perpendicular to a horizontal axis and to which a sheath is fixed. Since it is used as an intermediate mount, displacement of the intermediate portion of the sheath can be sufficiently absorbed.

In the gas insulated transmission line according to the seventh aspect of the present invention, a low friction sheet member made of a material having a low friction coefficient is attached to a sliding surface between the pedestal and the sheath support member. The displacement of the portion can be more smoothly absorbed.

The gas insulated transmission line according to the invention of claim 8 includes a pedestal fixed to a support structure disposed above the sheath, a sheath support member to which the sheath is fixed, and a pedestal and sheath support member. As a suspension platform with a link rotatably connected between them is used as an intermediate platform, seismic performance is ensured even when the required platform spacing cannot be secured at places that cross rivers and wide roads. The intermediate portion of the sheath can be supported with a simple structure while maintaining the same.

[Brief description of the drawings]

FIG. 1 is a plan view showing a part of a gas-insulated transmission line according to Embodiment 1 of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a plan view showing a state where a plurality of the gas-insulated transmission lines of FIG. 1 are connected.

FIG. 5 is an explanatory diagram showing an analysis model of a gas-insulated transmission line having no bent structure.

FIG. 6 is an explanatory diagram showing an example of the vibration mode of FIG.

FIG. 7 is an explanatory diagram showing another example of the vibration mode of FIG. 5;

FIG. 8 is an explanatory diagram showing an analysis model of a gas-insulated transmission line having a bent structure.

FIG. 9 is a relationship diagram showing a relationship between an eccentricity and a natural frequency of a gas-insulated transmission line having a bent structure.

FIG. 10 is a plan view showing a part of a gas-insulated transmission line according to Embodiment 2 of the present invention.

FIG. 10 is a sectional view taken along line XI-XI.

FIG. 12 is a perspective view showing a part of a gas-insulated transmission line according to Embodiment 3 of the present invention.

FIG. 13 is a side view showing the suspension base of FIG.

FIG. 14 is a configuration diagram illustrating an example of a conventional gas-insulated transmission line.

[Explanation of symbols]

2 electric conductor, 11, 21 sheath, 12 main frame, 1
4 elastic mount (intermediate mount), 16 elastic columns, 22 horizontal moving mount (intermediate mount), 23,33 pedestal, 24,3
5 Sheath support member, 26 Low friction sheet member, 31
Steel beams (supporting structures), 32 suspension frames (intermediate frames),
34 links.

Claims (8)

[Claims] 1. A sheath in which an insulating gas is filled, an electric conductor disposed in the sheath, and a gap between the sheath and an electric conductor for restraining displacement in a vertical direction and a direction perpendicular to a horizontal axis. A plurality of main frames supporting the sheath as described above, and the adjacent main frames installed between adjacent main frames to restrain displacement in the vertical direction and allow displacement in the axial direction and the horizontal axis perpendicular direction. An intermediate mount supporting the intermediate portion of the sheath between the sheaths, wherein the intermediate portion of the sheath is eccentric in a direction perpendicular to a horizontal axis with respect to a straight line connecting the adjacent mounts, and the intermediate portion from the straight line Wherein the eccentricity is 5% to 15% of the distance between the adjacent main frames. 2. The gas insulated transmission line according to claim 1, wherein an intermediate portion of the sheath is bent and eccentric. 3. A plurality of linear sheaths are connected to each other in a bent state, the center in the length direction of each of the sheaths is supported by a main gantry, and the bent connecting portion is supported by an intermediate gantry. 3. The gas insulated transmission line according to claim 2, wherein: 4. The gas insulated transmission line according to claim 1, wherein the middle portion of the sheath is eccentrically bent in an arc shape. 5. The gas according to claim 1, wherein the intermediate mount is an elastic mount having an elastic column elastically deformable in the axial direction of the sheath and in the direction perpendicular to the horizontal axis. Insulated power lines. 6. The intermediate gantry is a horizontal plane gantry having a pedestal, and a sheath supporting member slidably provided on the pedestal in an axial direction and a direction perpendicular to the horizontal axis and to which a sheath is fixed. The gas-insulated transmission line according to claim 1. 7. The gas insulation according to claim 6, wherein a low friction sheet member made of a material having a low friction coefficient is attached to a sliding surface between the base and the sheath support member. power line. 8. The intermediate pedestal includes a pedestal fixed to a support structure disposed above the sheath, a sheath support member to which the sheath is fixed, and a turn between the pedestal and the sheath support member. The gas insulated transmission line according to any one of claims 1 to 4, wherein the suspension frame has a link movably connected thereto.