JPH0447853Y2 - - Google Patents

Description

[Detailed explanation of the invention] "Industrial application field" This invention is an internal cooling type used for underground power transmission lines, etc.
It concerns CV cables.

"Conventional technology" In recent years, various measures have been proposed to increase the power transmission capacity of power cables in order to cope with the increase in power demand.
As one measure to increase the power transmission capacity, an internally cooled CV cable (hereinafter simply referred to as CV cable) as shown in FIG. 2 has been used.

In other words, this CV cable consists of a large number of strands 1
An insulating layer 3 made of cross-linked polyethylene is provided on the outside of the conductor 2 made of
It has a structure in which a refrigerant passage 5 made of a copper pipe or the like is provided inside the conductor 2, and a cooling medium such as water or fluorocarbon gas is passed from one end of the refrigerant passage 5 to the other end. Then, conductor 2
The strands 1 of the cable are cooled to increase the power transmission capacity of the cable.

However, since the CV cable is provided with only one refrigerant passage, in the cross section of the cable shown in FIG. In addition, in the length direction of the CV cable, the temperature of the strand 1 inevitably tends to increase gradually from the refrigerant inlet side to the outlet side.
Therefore, there is a problem in that the power transmission capacity is limited by the strands that have the worst cooling conditions. Further, since the cooling passage 5 is single, it is necessary to separately provide a return pipe for recovering the refrigerant, which raises the problem of increased construction cost.

``Problem that the invention attempts to solve'' This invention was made in view of the above-mentioned circumstances, and it increases power transmission capacity with high cooling capacity.
The purpose of the company is to provide CV cables, as well as CV cables with low construction costs.

"Means for Solving the Problems" The present invention was made to achieve the above-mentioned object, and its structure consists of a pipe-shaped inner wall in the center of the conductor 2, which is made up of a large number of wires bundled together. A refrigerant passage 6 is buried, and a plurality of outer refrigerant passages 7A to 7L each having a hollow fan-shaped cross section are closely combined to form a ring along the outside of the conductor, and an insulating layer 3 and an outer sheath 4 are provided around the outer refrigerant passage 6. The internally cooled CV cable is characterized in that the refrigerant is sequentially provided in the plural outer refrigerant passages, and refrigerant is caused to flow in the opposite direction in every other refrigerant passage. Note that a hollow fan-shaped cross-sectional tube is one that is hollow inside, has a large arc surface and a small arc surface, and has a fan-shaped cross section as a whole, and the outer refrigerant passage of the conductor has a large arc surface on the outside and a small arc surface on the inside. It is constructed by combining a plurality of strips closely together to form a ring.

"Function" With the above configuration, both the inner and outer cooling passages can be used as circulation passages for the outward and return passages, and the contact area between the refrigerant passage and the strands can be increased, and the power transmission capacity can be increased with a simple structure. We can provide CV cables with increased .

"Example" Hereinafter, an example of the present invention will be described. 1st
The figure shows an embodiment of the present invention, and the same parts as in FIG. 2 showing the conventional example are given the same reference numerals, so the explanation will be simplified.

The CV cable of the present invention as shown in the figure has a pipe-shaped inner refrigerant passage 6 made of a copper pipe or the like similar to the refrigerant passage of the conventional example described above buried inside the conductor, and a pipe-shaped inner refrigerant passage 6 made of a copper pipe etc. is buried inside the conductor. , a plurality of outer refrigerant passages 7A to 7L formed into hollow fan-shaped cross-sections using copper pipes or the like are closely combined and arranged in an annular shape, fixed on the conductor 2, and these outer refrigerant passages 7A ~7L is provided with an insulating layer made of cross-linked polyethylene on the outside, and is further covered with an external sheath 4 made of polyvinyl chloride, etc., and the refrigerant flows in the opposite direction every other outer refrigerant passage 7A~7L. It is something that

Such CV cables: (a) have a streamlined cable structure and do not require wraps in the outer refrigerant passage;

(b) Inner refrigerant passage 6 and outer refrigerant passage 7A to 7
L is effectively cooled as a reciprocating path for refrigerant, and in particular, the outer refrigerant paths 7A to 7L are made up of a large number of lines, and every other refrigerant path is directed in the opposite direction to improve cooling efficiency.

(c) The inner refrigerant passage 6 is used as an outbound passageway or a return passageway, and the refrigerant is circulated from one end to the other end;
In addition, since every other outer refrigerant passage 7A to 7L is used for an outgoing passage and an incoming passage, cooling can be performed efficiently while maintaining a minimum outer diameter, and the power transmission capacity of the cable can be increased.

(d) Since the outer refrigerant passage has a hollow fan-shaped cross section, the assembly maintains an almost perfect circular shape as a whole, and there are no gaps between the conductor, adjacent outer refrigerant passages, and the insulating layer; In addition, the large arc surface on the outside of the hollow sector-shaped pipe, that is, the insulating layer side, is the part where the potential gradient of the cable is greatest, so it is covered with a semiconducting layer. Unlike the case where a refrigerant passage is provided, no protrusions are formed even if the semiconductive layer is thin, so the outer diameter can be small.

(e) Adjacent outer refrigerant passages are also configured to have surface contact, and the refrigerants flow in opposite directions to exchange heat, so the heat exchange effect is large and the cooling efficiency by the refrigerant is good.

(f) A specific example of the effect of the present invention is shown in Fig. 3, in which the refrigerant temperature in the outward refrigerant passage increases from the base end of the cable to the distal end as shown by arrow A; As shown in B, the refrigerant temperature in the return refrigerant passage decreases from the tip to the base end of the cable, and corresponding to the temperature distribution in the refrigerant passage, the temperature of the conductor 2 increases as shown by arrow C. It changes like this.

"Effects of the invention" As is clear from the above explanation, the present invention embeds a pipe-shaped inner refrigerant passage in the core of a conductor consisting of a large number of strands, and has multiple strips of cross-section along the outer periphery of the conductor. An outer refrigerant passage consisting of a hollow fan-shaped tube is provided,
An insulating layer is provided on the outside, and an external sheath is provided on the outside.Alternatively, every other refrigerant path flows in the opposite direction, so the cable structure is strong and the conductor can be connected inside and outside. In addition to efficient cooling, the outer refrigerant path is separated into the outward and return paths, resulting in excellent cooling efficiency, less temperature rise in the conductor, less temperature deterioration of the insulator, and the use of circular tubes in the outer refrigerant path. The power transmission capacity of the CV cable can be efficiently increased compared to the case where the CV cable is used.

In other words, the provision of a hollow fan-shaped pipe as a refrigerant passage outside the conductor provides a structurally stable structure without the need for any pressure winding, and allows for heat exchange through surface contact with the conductor and insulator. Since the hollow sector-shaped pipes are in surface contact with each other, the cooling effect of the conductor is large, and since the fan-shaped outer refrigerant passage has a large internal space, the flow rate of refrigerant can be increased. Therefore, it goes without saying that the cooling efficiency is also good.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing an embodiment of the CV cable of the present invention, Figure 2 is a cross-sectional view of an embodiment of a conventional CV cable, and Figure 3 is a refrigerant and cable in the CV cable of the present invention. 2 is a graph showing the temperature distribution of . 1... Element wire, 2... Conductor, 3... Insulating layer, 4...
...Outer sheath, 6...Inner refrigerant passage, 7...Outer refrigerant passage.

Claims (1)

[Scope of utility model registration request] A pipe-shaped inner refrigerant passage 6 is buried in the center of a conductor 2 made of a large number of bundled wires, and a plurality of outer refrigerant passages 7A to 7L each made of a hollow fan-shaped cross section are closely connected along the outside of the conductor. The interior is characterized in that the combinations are provided in an annular shape, an insulating layer 3 and an external sheath 4 are sequentially provided around the insulating layer 3, and a refrigerant is caused to flow in opposite directions in every other one of the plurality of outer refrigerant passages. Cooled CV cable.