JPH074729Y2 - Internally cooled power cable - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an internally-cooled power cable that increases the power transmission capacity by directly removing the heat generated by the cable from the inside of the conductor with a refrigerant.

[Conventional technology]

Conventionally, there is an OF cable, for example, which directly absorbs heat generated by the cable from the inside of the conductor. This OF cable has an oil passage inside the sheath, filled with low viscosity insulating oil in a degassed and dehumidified state, and constantly applies a pressure above atmospheric pressure by an oil tank installed outside to create a gap in the insulator. Do not make up full oil-impregnated paper insulation. Also, an internally cooled cable using a refrigerant such as CFC gas instead of the insulating oil has been put into practical use.

[Problems to be solved by the device]

However, in the above OF cable, the oil passage for directly absorbing the heat generation of the cable from the inside of the conductor is provided only in the central part of the conductor, so the cooling surface area due to the insulating oil is small, and the cooling of the conductor is not possible. Efficiency is low. As a result, the conductor heats up and the insulation inside the cable deteriorates,
There is a problem that the current capacity becomes small.

Even in an internally cooled cable that uses a refrigerant such as freon gas instead of insulating oil, as the one that directly absorbs the heat generated by the cable from the inside of the conductor, the refrigerant passage is only in the center of the conductor, as in the case of the above-mentioned OF cable. Because it is not provided,
The above problems still remain.

Therefore, the present invention has been made in consideration of the above circumstances.
It is an object of the present invention to provide an internally cooled power cable which has improved cooling efficiency for conductors and improved allowable tensile strength.

[Means for Solving the Problems]

In order to achieve the above object, in the internally cooled power cable of the present invention, a copper wire is inserted into each of the tension member pipes in which a plurality of strands are twisted, and the inner circumference of the pipe and the copper wire are It is characterized in that it has a conductor having a void portion formed therebetween, and a coolant is circulated in the void portion.

[Action]

In the present invention having the above structure, a copper wire is inserted into each of the tension member pipes in which a plurality of conductors are twisted, and a gap is formed between the inner circumference of the pipe and the copper wire. As a result, the tensile strength of the cable as a whole is high, and moreover, the refrigerant is circulated in the voids to cool each tension member pipe from the inner peripheral direction or the copper wire inserted thereinto from the outer peripheral direction. Will increase. As a result, the efficiency of cooling the conductor is increased, and heat generation of the conductor can be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
1 is a cross-sectional view showing an embodiment of an internally cooled power cable according to the present invention, in which an internally cooled power cable 1 includes a cable conductor 2, an inner semi-conductive layer 3, a polyethylene insulating layer 4, and an outer half. Conductive layers 5 are sequentially provided, and usually the inner semiconductive layer 3, the polyethylene insulating layer 4 and the outer semiconductive layer 5 are formed by a co-extrusion method, and the space between the inner semiconductive layer 3 and the polyethylene insulating layer 4 and the insulating layer are formed. 4 and the outer semiconductive layer 5 are integrated. The outer circumference of the outer semiconductive layer 5 is covered with a cable sheath 6 made of plastic or metal to form a single-core CV cable.

The cable conductor 2 is made of stainless steel (SUS316), dispersed copper alloy Cu-12Nb (Nb weight% 1 to 12), Cu-A1 ₂ O _3, etc., and has a tension member with an inner diameter of 0.5 to 10 mm. A plurality of pipes 2a are twisted together, and a copper wire 2b having an outer diameter of 1 to 5 mm is inserted through each tension member pipe 2a. Here, in order to insert the copper wire 2b into the tension member pipe 2a, the plurality of pipes 2a are twisted together while being vibrated. Then, the refrigerant composed of gas and liquid is circulated in the space 2c formed by the inner circumference of the tension member pipe 2a and the copper wire 2b.

FIG. 2 shows a cooling device for an internally cooled power cable according to this embodiment. In FIG. 2, each tension member pipe 2a of the internally cooled power cable 1 is connected to a refrigerant supply pipe 10, and this refrigerant supply pipe 10 is connected. Refrigerant circulation pump that circulates the refrigerant in the 1
1, a heat exchanger 12 and a precooler 13 are provided. Further, a cooling water pipe 14 is connected to the heat exchanger 12, and the cooling water is circulated by a cooling water pump 16 installed in the heat storage tank 15. In the heat storage tank 15, a cold water circulation pump 18 for circulating the cold water from the refrigerator 17 is installed.
17 is equipped with a cooling tower 19. Then, in the internally cooled power cable 1, each tension member pipe 2a is connected to the refrigerant supply pipe 10 at the refrigerant supply connection portion 20, and the copper wire 2b is connected to the copper wire of the power cable in the next cooling section.

In the above configuration, the refrigerator 17 cools the water in the heat storage tank 15, circulates the cooling water in the heat storage tank 15 to the heat exchanger 12 by the cooling water pump 16, and the cooling water and the refrigerant in the heat exchanger 12. Are heat-exchanged, and this refrigerant is circulated in each tension member pipe 2a of the power cable 1 by the refrigerant circulation pump 11 to cool the cable conductor 2.

Next, the operation of this embodiment will be described.

In the cable conductor 2, the tension member pipe 2a
Since a plurality of cables are twisted together, the allowable tensile strength and the allowable lateral pressure of the cable as a whole are significantly increased. As a result, the cable pull-in length is increased and the joint section length is also increased. And each tension member pipe 2a has an inner diameter of 0.
It has a small diameter of 5 to 10 mm, and since multiple strands are twisted together, it has good flexibility as a power cable.

Further, in this embodiment, the copper wire 2b is inserted into each of the tension member pipes 2a, and a void portion 2c is formed between the inner circumference of the tension member pipe 2a and the copper wire 2b, and the refrigerant is introduced into the void portion 2c. By distributing, each tension member pipe
2a is cooled from the inner peripheral direction, or the copper wire 2b inserted therein is cooled from the outer peripheral direction, increasing the cooling surface area,
It is possible to improve the cooling efficiency for the cable conductor 2 and prevent the conductor 2 from generating heat.

Furthermore, each tension member pipe 2a is made of stainless steel (SUS316), dispersed copper alloy Cu-12Nb (Nb weight% 1 to 1).
2), because it is a conductor material of Cu-A1 ₂ O ₃ , the skin effect of the cable conductor 2 can be reduced.

In the above embodiment, each tension member pipe
When the fiber reinforced plastic is used for 2a, the weight of the electric power cable 1 as a whole is reduced, the handleability is improved, and the cable conductor 2 is not corroded.

In addition, in the above-described embodiment, if holes of an appropriate size are formed in each tension member pipe 2a at a constant direction and at regular intervals, the refrigerant will spread evenly to the cable conductor 2 and the cooling efficiency will be further enhanced. it can.

Furthermore, if the void 2c of each tension member pipe 2a is held in a vacuum and liquid such as water or alcohol is enclosed in this void 2c to make the tension member pipe 2a a heat pipe, the cooling device shown in FIG. Is no longer needed,
Equipment costs will be significantly reduced.

[Effect of device]

As described above, according to the internally cooled power cable according to the present invention,
A copper wire is inserted into each of the tension member pipes that are twisted together, and a conductor having a void is formed between the inner circumference of the tension member pipe and the copper wire, and the refrigerant is circulated in the void. Therefore, the allowable tensile strength and the allowable lateral pressure of the cable as a whole are significantly increased, the cable pull-in length is increased, and the joint section length is also increased.

In addition, since the cooling medium is circulated in the voids to cool each tension member pipe from the inner peripheral direction or the copper wire inserted thereinto from the outer peripheral direction, respectively, the cooling surface area is increased and the conductor is cooled. The efficiency is enhanced and the heat generation of the conductor can be prevented. As a result, it is possible to prevent deterioration of the insulating layer due to heat generation of the conductor and to provide an internally-cooled power cable having a significantly increased power transmission capacity.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an internally cooled power cable according to the present invention, and FIG. 2 is a schematic view showing a cooling device for an internally cooled power cable according to this embodiment. 1 …… Internally cooled power cable, 2 …… Cable conductor, 2a ……
Tension member pipe, 2b …… Copper wire, 2c …… Gap, 4
…… Insulation layer.

Claims (4)

[Scope of utility model registration request] 1. A conductor having a copper wire inserted into each of a plurality of twisted tension member pipes and having a void between the inner circumference of the pipe and the copper wire, wherein the refrigerant is placed in the void. An internally-cooled power cable characterized by being distributed. 2. Each tension member pipe has a fixed direction,
The internally cooled power cable according to claim 1, wherein holes are formed at regular intervals. 3. The internally cooled power cable according to claim 1, wherein each tension member pipe is a heat pipe. 4. The internally cooled power cable according to claim 1, 2 or 3, wherein each tension member pipe is an electric conductor.