JPS63314114A - Laying system for cable - Google Patents

Abstract

PURPOSE:To reduce sheath eddy current loss and induction to a control wire, by arranging three strips of cable at the respective apexes of a triangle, and by setting a cooling pipe on the center of the triangle via a spacer. CONSTITUTION:The cable strips 21, 22, 23 of three-phase component are arranged at the respective apexes of an equilateral triangle, and on the center of the triangle, a cooling pipe 3 is set via a spacer 4. In other words, the cable stripe 21, 22, 23 are arranged so that the shape of the cable strips may be engaged with a recessed section formed at the respective apexes of the spacer 4 of the equilateral triangle, and the respective strips are positioned at an almost equal distance from the cooling pipe 3. Then, the strips are compacted in relation to such a position, and so a trough 1 can be miniaturized, and sheath eddy current loss can he reduced, and the induction of a control wire in close contact with is comparatively less. Besides, the respective thermal actions of the cable strips 21, 22, 23 and the cooling pipe 3 can be allowed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cable installation method, and more particularly to a cable installation method in which cables for one line and three phases are provided together with their cooling pipes in one trough.

A conventional cable installation method of this type will be explained with reference to FIGS. 2 and 3. In these figures, 1 is a trough, 2 is a cable, and 3.31°32 is a cooling pipe.

In the system shown in FIG.
This system has a small amount of induction into nearby control lines, etc., but the sheath eddy current loss is large. In addition, in the method shown in FIG. 3, the three phases of the cable 2 are arranged in a triangle with adjacent phases separated, and the cooling pipe 3 is installed in the upper part of the trough 1. This method uses a sheath vortex. Although current losses can be reduced, the trough 1 becomes significantly larger and therefore requires a larger tunnel.

These are the one with bale stacking and the one with triangular layout.
A comparison of the sheath eddy current failure rate and control line induced voltage for a 275KV1X2000m20F cable is as shown in the following table.

In the table, the phase spacing in the case of installation in an equilateral triangle arrangement was 260M, the phase spacing in the case of phase separation installation was 480#, and the experiment was conducted with the spacing between the control line and the cable being 700M.

This experimental result shows that sheath eddy current loss can be reduced by separating the three phases of cable 2, but
If the distance between adjacent phases is increased, the trough 1 becomes larger, which means that the tunnel must also be made larger, which poses a problem in cable installation.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and to provide a cable installation method that reduces both sheath eddy current loss and control line induction, and can be housed in a small trough.

That is, the present invention provides cables for one line, three phases, and their cold I.
JIt2. In a cable laying method in which a cable is installed in one trough, three cables are arranged at predetermined intervals in the laying line so as to occupy each vertex of an equilateral triangle,
A laying structure with a cross section in which one cooling pipe is attached via a spacer is provided at the center of the inside, and three cables are placed at each vertex of an equilateral triangle at required locations in the middle. A single cooling pipe supported by a spacer is attached to the center, and a middle support is provided between the cable at the top of the equilateral triangle and the two cables at the bottom. It is characterized by providing a laying structure in which two supported cooling pipes are attached to both sides of the cable at the top.

An embodiment of the present invention will be described below with reference to FIGS. 1(A) and 1(B). Figure 1 (a) is a diagram for explaining the outline of the cross section of the part where one cooling pipe is attached to three cables, and the same figure (b) is a diagram for explaining the outline of the cross section of the part where one cooling pipe is attached to three cables. It is a figure for explaining the outline of the cross section of the part to which a cooling pipe is attached.

In Fig. 1 (a), cables 21, 22, and 23 are for one line and three phases, and are arranged so as to occupy each vertex of an equilateral triangle, and a cooling pipe 3 is installed in the center of the cable through a spacer 4. ing. That is, the cables 21, 22, 23 are
The spacers 4 are arranged to engage with recesses formed at the vertices of the spacer 4, which is equilaterally triangular in shape, and are located at approximately the same distance from the cooling pipes 3. This installation structure consists of cable 2
1.22.23 and the cooling pipe 3 have the above-mentioned position N relationship and are compactly arranged, so the trough 1 can be made smaller and the sheath eddy current can be reduced compared to, for example, the conventional method shown in FIG. Loss can be reduced, and induction of adjacent control lines is also relatively small. Also, cables 21.22. ．． 23 and the cooling pipes 3; furthermore, by changing the shape of the spacer 4, the cables 21, 22
23 can also be arranged at arbitrary intervals. 1st above
The laying structure shown in Figure (A) is provided at regular intervals in the longitudinal direction of the cable laying line.

Next, FIG. 1(b) shows the installation structure of a portion in which two cooling pipes are added, and is applied in combination with the t5 installation structure of FIG. 1(a) in the laying line. As shown in the figure, this installation structure consists of cables 21, 22, .
At the center of 23, there is a single cooling pipe 31 supported by a spacer 4'. Furthermore, an interrupted support 5 is provided between the top cable 21 and the other two cables 22, 23, and the top cable 21 and two cooling pipes 32, 33 are placed on the upper surface of this suspension support 5. It is arranged to be One of the purposes of this laying structure is to support the sagging distortion in the intermediate portion of the laying structure shown in FIG. 1(a), which is provided at regular intervals in the longitudinal direction of the line. Additionally, sheath eddy current loss and induction into the control line are also small. Another purpose of arranging the installation structure shown in FIG. 1(b) is that, as will be described later, cold IA pipes can be added to increase the cooling effect without increasing the size of the trough. That is, for example, 275KV,
For a lX2000mm2 OF cable, the snake pitch is 9m and the snake width is 1.5D (D-cable outer diameter).
It is appropriate to Further, the distance between the cable 21 or the cable 23 and the inner wall of the trough 1 is at least 0.7
In this case, the distance between the cable 21 and the inner wall of the trough 1 is 1.75D, and the cable 2
A gap of 1D from the snake of 0.75D remains.

Therefore, by combining the laying structure shown in FIG. 1(A) and the laying structure shown in FIG. 1(B), the cooling effect can be enhanced without changing the size of the trough 1.

As explained above, according to the cable installation method of the present invention, the cable and its cooling pipe can be housed and installed in a small trough, and moreover, sheath eddy current loss and guidance to the control line can be reduced. It can have the practical effect of being made smaller.

[Brief explanation of the drawing]

Figure 1 (A) shows a cold 19 cable in three cables according to an embodiment of the present invention.
A schematic cross-sectional view of the installation structure part to which one pipe is attached, Figure (B) is a schematic cross-sectional view of the installation structure part to which three cables and three cooling pipes are attached, Figures 2 and 3. The figure is a schematic cross-sectional view of a cable laying structure in a conventional cable laying method. 1 Nidraft, 2.21.22, 23: Cable, 3.31.32.33: Cooling pipe, 4.4' varnish spacer, 5: Middle support.

Claims (1)

[Claims] In a cable laying method in which cables for three phases of one line and their cooling pipes are provided in one trough, three cables 21, 22, 23 are arranged at predetermined intervals in the longitudinal direction of the laying line.
are placed at each vertex of an equilateral triangle, and a spacer 4 is placed in the center.
An installation structure is provided in which one cooling pipe 3 is attached through the cable, and three cables 21, 22,
23 are placed at each vertex of an equilateral triangle, and one cooling pipe 31 supported by a spacer 4' is attached to the center thereof, and the top cable 21 and two other cooling pipes are attached on both sides of the top cable 21. A cable laying method characterized by providing a laying structure in which two cooling pipes 32, 33 are attached, supported by a middle support 5 provided between the cables 22, 23.