JP2000057862A - Unit for compressed gas insulated transmission line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a unit capable of being reduced in diameter and easily absorbing thermal expansion and contraction of a conductor. SOLUTION: This unit includes a sheath pipe 1 and a conductor enclosed in the sheath pipe 1, the conductor having a conductor pipe 2 and a stranded conductor 3 enclosed in the conductor pipe 2. A connecting terminal is provided at each end of the conductor. The connecting terminal is preferably a terminal board 8 pressed against the stranded conductor 3. Since the stranded conductor 3 needs only to be drawn into the conductor pipe in advance by unit length and does not need to secure a large gap to the conductor pipe 2, the outside diameter of the conductor pipe 2 can be reduced and the outside diameter of the sheath pipe 1 can also be reduced. The amounts of thermal expansion and contraction can easily be absorbed by meandering the stranded conductor 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit constituting a pipeline air transmission line. In particular, the present invention relates to a unit for a pipeline air transmission line having a conductor mainly composed of a wire in order to improve a current carrying capacity.

[0002]

2. Description of the Related Art Conventional pipeline air transmission lines (hereinafter referred to as GIL "Ga
s Insulated Transmission Line ") is shown in Fig. 7. In a sheath tube 20 made of a metal pipe, one or more conductors also made of a metal pipe are provided.
This is a structure in which the insulating gas 21 is housed and the insulating gas 22 is pressed into the sheath tube. The transmission line is constituted by connecting a plurality of units by a sheath connection part 23 and a PIC 24 (plug-in contact). Each unit is about several meters to several tens of meters. Here, an example in which two units are connected is shown. The conductor 21 is fixed in the sheath tube by a spacer 25.

[0003] The GIL is one of those compared to ordinary power cables.
One of the features is that the current that can be passed through the book, that is, the allowable current is large, and it is used as a large-capacity transmission line alongside ordinary oil-insulated cables and plastic-insulated cables.

The cross-sectional size of such a GIL, that is, the outer diameter of the sheath tube, is determined based on the required insulation properties and the current-carrying performance.

The conductor is usually formed of an aluminum alloy pipe, and the current carrying capacity is determined by the cross-sectional area of the pipe. However, since the current flows intensively near the pipe surface due to the skin effect of the alternating current, the pipe thickness is about 20 mm. Even if it is thicker, the current capacity does not increase. Therefore, in order to improve the current carrying capacity of the GIL, it is essential to increase the diameter of the metal pipe forming the conductor. In addition, since a certain gap or more is required between the conductor and the sheath tube for insulation, the overall GI
The size of L had to be increased.

[0006] As a GIL having a different structure, a conductor pull-in type GIL has been proposed. Although this is a line in which an insulating gas is sealed in a sheath tube, a metal pipe is not used as a conductor, but a draw-in tube is provided in advance at a position in the sheath tube where a conductor is to be provided. When connecting the unit, connect the sheath tube and the retracting tube with a simple structure such as insertion, and construct a line of a certain length,
Thereafter, the wire conductor is drawn into the drawing pipe. This conductor pull-in type GIL is a structural plan mainly aimed at cost reduction by reducing the number of conductor connection points on site.

[0007]

However, the conventional GIL
In each case, it was difficult to reduce the diameter. In a GIL using a metal pipe as a conductor, it is necessary to increase the diameter of the metal pipe in order to improve the current capacity, and it is difficult to reduce the diameter.

Further, in order to obtain a current carrying capacity equivalent to that of an aluminum alloy pipe (conductor) in a GIL of a conductor pull-in type, a stranded wire conductor having a smaller diameter than the aluminum alloy pipe can be used instead.
However, long distance drawing requires a certain gap between the drawing tube and the stranded wire conductor, so the size of the drawing tube needs to be larger than that of the stranded wire conductor, making it difficult to reduce the diameter. Met. Further, this structure has a drawback that the structure for absorbing the thermal expansion and contraction of the stranded wire conductor due to heat generation is complicated.

[0009]

According to the present invention, the conductor of each unit for a pipeline air transmission line is constituted by a conductor tube and a stranded conductor housed therein, and connection terminals are provided at both ends of the conductor. Solves the above problem.

By using a wire conductor as the conductor, a conductor having the same AC resistance as the aluminum pipe can be formed with a smaller outer diameter. That is, if the stranded conductor is made of, for example, a copper stranded wire insulated from the strand, the skin effect as a whole as in an aluminum pipe is small, and it is not necessary to have a hollow structure. Therefore, to obtain the same cross-sectional area, a smaller outer diameter may be used, and if the material is copper, the resistance is smaller than that of aluminum, so that the same current-carrying capacity can be secured with a smaller cross-sectional area.

Further, the stranded conductor is pre-configured with a length corresponding to the unit length (the length of the sheath tube or the conductor tube) and has connection structures at both ends. Tracks can be constructed by simply bringing in the units and connecting the units each time.

[0012] However, since the mechanical strength of the stranded conductor alone is weak and soft, it is difficult to support the gas in the sheath tube by the insulating spacer. Therefore, it is necessary to house the conductor in a strong conductor tube. The material of the conductor tube may be aluminum alloy or stainless steel, but is not particularly limited.

Here, the specific configuration of the connection terminal is as follows. Bolt-fastening-type fittings A structure in which bolt-fastening-type fittings (so-called feather board terminals), which are used for connecting conductors, are attached to both ends of a stranded wire conductor. In this structure, since the wire conductors are directly connected to each other, it is necessary to separately connect the conductor tubes, which are storage tubes, so as to cover the connection terminals.

A fastener having a slide structure is a specific example of a PIC used in a conventional GIL or the like, and absorbs thermal expansion and contraction of a conductor in this joint portion while maintaining the current-carrying performance. is there. Since the PIC is fixed to the conductor tube and has a structure for connecting the conductor tubes to each other, it is necessary that the built-in stranded wire conductor and the PIC are electrically connected.

Further, in the above-mentioned unit structure, the following structure can be mentioned as a structure for absorbing or facilitating the thermal expansion and contraction of the wire conductor.

The stranded conductor is mechanically fixed to the conductor tube at one end of the conductor tube and not fixed at the other end. Thus, expansion and contraction of the stranded conductor becomes a problem within the range of each unit, and does not affect the next connected unit. That is, a structure may be adopted in which the conductor elongation at the maximum conductor temperature of the unit length is absorbed by sliding the unit connection portion or deforming the conductor in the unit.

The stranded conductor has a structure in which a plurality of stranded wires are further combined. With this structure, when the conductor is stretched, the entire wire conductor is deformed so as to be separated from each other, thereby facilitating absorption of the stretch.

The stranded conductor is mechanically fixed at both ends of the conductor tube, and is externally an integral pipe-shaped conductor. This structure can be handled in the same manner as a conventional aluminum pipe type conductor. For the expansion and contraction absorption, it is preferable to attach PICs to both ends of the conductor tube.

[0019]

Embodiments of the present invention will be described below. FIG. 1A is a longitudinal sectional view of a GIL constituted by the unit of the present invention, and FIG. 1B is a transverse sectional view thereof. here
This shows a state where two units are connected.

Each unit comprises a sheath tube 1 located at the outermost periphery, a conductor tube 2 built in the sheath tube 1 and a conductor tube 2.
And the stranded wire conductor 3 housed in the housing. The conductor tube 2 is coaxially supported in the sheath tube by a plurality of spacers 4. The units are connected to each other by a sheath connection portion 5 and a connection terminal 6. An insulating gas 7 such as SF ₆ is press-fitted into the sheath tube.

For the sheath tube 1, an aluminum alloy pipe is usually used. The conductor tube 2 is desirably a non-magnetic metal in order to avoid adverse effects such as heat generation due to a magnetic field during energization, and an aluminum alloy is preferable in terms of contributing to energization performance, and stainless steel is preferable in terms of mechanical strength. The stranded conductor 3 is formed by twisting a plurality of strands, and preferably has an insulating coating formed on each strand. Since the stranded conductor 3 only needs to be drawn into the conductor tube in advance for the length of the unit length,
It is not necessary to make the gap between the conductor tube and 3 large, and the conductor tube 2 only needs to be larger than the stranded wire conductor 3 by the gap required for assembly.

The specific structure of each unit is shown below. FIG. 2 shows an example in which a bolt fastening type terminal plate 8, a so-called blade terminal, is attached as a connection terminal to the end of the stranded conductor.
The terminal plate 8 may be crimped to the stranded conductor 3. In the structure of this figure, since the stranded conductor 3 and the conductor tube 2 are not fixed, the stranded wire conductor 3 can move in the conductor tube, and the thermal expansion and contraction is absorbed by the displacement of the stranded conductor 3 and the meandering in the conductor tube. You.

FIG. 3 shows a structure in which PICs 9A and 9B are used as connection terminals, similarly to a conventional GIL. The PIC is composed of a plug 9A and a socket 9B. The plug 9A is connected to one end of the conductor tube 2 and the socket 9B is connected to the other end. The thermal expansion and contraction can be absorbed by the connecting portion composed of the plug 9A and the socket 9B. The stranded conductor 3 is fixed to the conductor tube 2 at both ends.

FIG. 4 shows a modification of the structure shown in FIG. 2, in which one end of the stranded conductor 3 is fixed by a conductor fixing portion 10 in a conductor tube. Therefore, when these units are sequentially connected, the thermal expansion and contraction of the stranded wire conductor 3 is not fixed (right side in FIG. 4).
Since the expansion and contraction within the unit is absorbed only within the unit, the behavior of the conductor is stable even when a long line is configured.

FIG. 5 shows an example in which a stranded conductor 3 in which a plurality of stranded wires 11 are further twisted is housed in a conductor tube. Here, both ends of the stranded wire conductor 3 are fixed to the conductor tube 2 by a conductor fixing portion 12, and PICs 9A and 9B are used as connection terminals. The cross section of the stranded conductor 3 has a structure in which three stranded wires 11 are stranded as shown in FIG. 6, for example. With this structure,
Even when the stranded wire conductor 3 is thermally expanded and the amount of extension of the stranded wire conductor 3 is larger than that of the stranded conductor tube 2, the stranded wire conductor 3 is separated in the conductor tube to absorb the extension. Can be.

[0026]

As described above, according to the present invention, the conductor of each unit for a pipeline air transmission line is constituted by a conductor tube and a stranded conductor housed inside the conductor tube and connected to both ends of the conductor. The following effects are obtained by providing the terminals.

By using a wire conductor as the main part of the conductor, a conductor having the same AC resistance as the metal pipe can be formed with a smaller outer diameter.

It is sufficient that only the unit length of the stranded wire conductor is drawn into the conductor tube in advance, and it is not necessary to make a gap with the conductor tube large. Therefore, the conductor tube needs to be larger than the stranded conductor by the gap required for assembly, so that the outer diameter of the conductor tube can be reduced and the outer diameter of the sheath tube can be reduced.

Since the stranded wire conductor is pre-configured with a length corresponding to the unit length and has a connection structure at both ends, a line can be formed simply by carrying in the field for each unit and connecting the units.

By forming the main part of the conductor with a stranded wire conductor, a structure for absorbing thermal expansion and contraction of the conductor can be easily formed.

[Brief description of the drawings]

1A and 1B show an internal configuration of a GIL constituted by a unit of the present invention, wherein FIG. 1A is a longitudinal sectional view and FIG. 1B is a transverse sectional view.

FIG. 2 is an internal configuration diagram of the unit of the present invention in which a stranded wire terminal is provided at both ends of a stranded wire conductor.

FIG. 3 is an internal configuration diagram of the unit of the present invention in which PICs are provided at both ends of a conductor.

FIG. 4 is an internal configuration diagram of a unit of the present invention in which a blade terminal is provided at both ends of a stranded wire conductor and only one side of the stranded wire conductor is fixed to a conductor tube.

FIG. 5 is an internal configuration diagram of the unit of the present invention in which PICs are provided at both ends using a plurality of stranded wires as conductors.

FIG. 6 is a sectional view of a plurality of stranded wires in FIG. 5;

7A and 7B show an internal configuration of a conventional GIL using a metal pipe as a conductor, where FIG. 7A is a longitudinal sectional view and FIG. 7B is a transverse sectional view.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sheath pipe 2 Conductor pipe 3 Stranded conductor 4 Spacer 5 Sheath connection part 6 Connection terminal 7 Insulating gas 8
Terminal plate 9A plug 9B socket 10 Conductor fixing part 11 Stranded wire 12 Conductor fixing part 20 Sheath tube 21 Conductor 22 Insulating gas 23 Sheath tube connection 24P
IC 25 spacer

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[Procedure amendment]

[Submission date] September 9, 1999 (1999.9.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Claims (6)

[Claims] 1. A conductor tube comprising: a sheath tube; and a conductor housed in the sheath tube. The conductor includes a conductor tube and a stranded conductor housed in the conductor tube, and connection terminals are provided at both ends of the conductor. A unit for a pipeline air transmission line, characterized by being provided. 2. The unit according to claim 1, wherein the connection terminal is a terminal plate crimped to the stranded conductor. 3. The sliding terminal according to claim 1, wherein the connecting terminal is a sliding fastener fixed to an end of the conductor tube, and the stranded conductor and the sliding fastener are electrically connected.
A unit for a pipeline air transmission line as described in the above. 4. The conduit air according to claim 2, wherein the stranded conductor is mechanically fixed to the conductor tube at one end of the conductor tube and is not mechanically fixed to the conductor tube at the other end. Unit for medium power transmission lines. 5. The unit according to claim 1, wherein the stranded conductor has a structure in which a plurality of stranded wires are further twisted. 6. The unit according to claim 1, wherein the stranded conductor is mechanically fixed to and electrically connected to the conductor tube at both ends of the conductor tube.