JPS5915250B2 - Cable forced cooling line - Google Patents

Description

Detailed Description of the Invention 5 The present invention allows a liquid that easily evaporates to flow through an airtight pipe provided inside a conductor of a cable, cools the cable by utilizing the latent heat of vaporization of this liquid, and also installs a small pipe inside the pipe. The invention relates to a cable line that is provided for forced cooling by natural circulation of liquid.

10 Conventionally, a device has been used in which an airtight pipe is provided inside the conductor of a cable, a liquid that easily vaporizes is flowed into the pipe, and the cable is forcibly cooled using the latent heat of vaporization of the liquid.

This forced cooling system has a pipe 2' with an airtight wall inside the conductor 1' of cable 15, as shown in Figure 3 (the line is shown only by the pipe inside the conductor), and water and fluorocarbons are placed inside this pipe z. The conductor 1' is heated to vaporize the liquid 3', and the conductor 1' is cooled by the latent heat of vaporization. 0 and one end 5 of the cable line.
At ', the pipe 2' and the small pipe 4' are communicated, and at the terminal end 6' at the other end of the cable line, the vaporized gas is cooled and liquefied by the fins 8' at a position higher than the terminal end 5'. In this specification, this is called a reservoir)
Set T' to 5 and set this reservoir? A small pipe 4' is connected to the gas phase part 9' of the pipe 2' to the liquid phase part 10', and the liquid 3' vaporized by the heating of the conductor 1' is re-liquefied and sent to the small pipe 4'. Further, at the terminal end 5', the water flows from the small pipe 4' to the pipe 2'. In this way, the liquid 3' in the cable conductor 1'o is naturally circulated through the cable end 6', the reservoir T', the small pipe 4', the end 5', and the pipe 2'. The cable is circulated by the difference between the heads of the cable, and the cable line is forcibly cooled. In such a conventional cable cooling system 15, a small pipe 4' is separately provided outside the cable line as a liquid supply path, and the pipe 4' is connected to a pipe inside the cable conductor 1' at both ends of the cable line. Since the cable conductor 1'' for large-capacity power transmission is at a high potential, it is technically difficult to connect the pipe 2' and the small pipe, requiring an insulator 1'' and requiring equipment funding. It is also expensive.

Particularly in large-capacity power transmission, the terminal end is often of a closed type like an elephant head, making it technically extremely difficult to communicate the pipe 2' with the small pipe. In view of this, the present invention facilitates communication by arranging a small pipe for liquid return within an airtight pipe within the cable conductor. Insert a small pipe into the airtight pipe at one end of the cable line, connect the airtight pipe to the small pipe at one end, and connect the airtight pipe to the gas phase part of the reservoir installed at a higher place than the communication end at the other end, and the small pipe to the liquid phase part. The pipes are connected to each other, and the liquid inside the pipes is circulated for forced cooling.

Next, this will be explained in more detail based on the drawings.

FIG. 1 is an explanatory diagram showing an example of a cable reinforcement line according to the present invention, and FIG. 2 is a cross-sectional view of a cable used for the same line.
is provided, and a liquid 3 that easily vaporizes, such as water or fluorocarbon, flows into this pipe 2. Furthermore, a small pipe 4 is inserted into this pipe 2 via a material with high thermal resistance, and this small pipe 4 is used as a supply path for the liquid 3. (Figure 1 only shows the pipe inside the conductor to simplify the diagram.) That is, the airtight pipe 2 and the small pipe 4 provided inside it communicate with each other at one end, that is, at the terminal end 5 or at an intermediate connection (not shown). At the terminal end 6 at the other end, an airtight pipe 2 is connected to the gas phase part 9 of the reservoir 7, which is provided at a higher place than the terminal end 5 or the intermediate connection part.
The liquid 3 is vaporized by the heat generated in the conductor 1, and the conductor 1 is cooled by the latent heat of vaporization, and is further vaporized and gasified. Liquid 3 passes through pipe 2 and enters gas phase 9 of reservoir 7.
The liquid flows into the reservoir 7, where it is cooled and liquefied, and stored in the liquid phase portion 10. The liquid in the liquid phase part 10 passes through the small pipe 4 and flows into the pipe 2 at the terminal end 5 or intermediate connection,
This cools the conductor 1 and naturally circulates to forcefully cool the conductor 1, that is, the cable. When the liquid 3 circulates, the small pipe 4 itself is made of Teflon, stainless steel, etc., which has high thermal resistance like the copper conductor of the cable, or it is made of a material with high thermal resistance such as nylon, Teflon, polyethylene, etc. between it and the pipe 2. , the liquid in the small pipe 4 is not vaporized and flows into the terminal end 5 or the intermediate connection, where it flows into the pipe 2 and serves to cool the conductor 1. In the present invention, the conductor 1 is cooled by the easily vaporized liquid 3 flowing inside the conductor 1, and the vaporized gas is liquefied by the reservoir 7 provided at one end of the line, and the gas is liquefied and circulated naturally, thereby performing forced cooling. Although it is the same as the conventional one, since the small pipe 4 that feeds back the re-liquefied liquid is provided inside the airtight pipe 2 in the cable conductor 1, communication between the airtight pipe 2 and the small pipe 4 is easy, and Since a material with high thermal resistance is interposed between the small pipe 4 and the airtight pipe 2, the liquid in the small pipe 4 is rarely heated, and the small pipe 4 can be used as a feedback pipe for the liquid 3. It is.

In the figure, 8 indicates a heat dissipation fin of the reservoir r, 11 indicates an insulating layer of the cable, and 12 indicates a protective sheath of the cable.
Furthermore, if a pump is provided between the small pipe 4 and the liquid phase portion 10 of the reservoir 7 to increase the circulation of the liquid 3, the cooling effect can be improved. Next, at 154kV, a copper pipe with an inner diameter of 50uUφ was inserted into a conductor with an effective conductor cross-sectional area of about 20007E12, and further into this copper pipe an inner diameter of 16m1φ and a wall thickness of 2
Insert the mu Teflon pipe and add Freon 11 as a liquid.
and water, the total cable length is approximately 20m, and the reservoir is 5.
When we conducted a forced cooling experiment with the pipe installed at a height of 3 m and the height of the communicating end of the pipe was 3 m, the conductor temperature reached 75 °C with a current of 1500 A without cooling, but with the pipe using Freon 11. In the cooling line of the invention, the conductor temperature was 60° C. with a conductor current of 4,500 A, and in the case of the cooling line using water, the conductor temperature was 78° C. with a conductor current of 5,500 A, which clearly showed a cooling effect.

As explained above, according to the present invention, a small pipe is inserted into an airtight pipe inside a conductor through a material with high thermal resistance,
Since it is used as a feedback pipe for the cooling liquid inside the pipe, it is easy to communicate between the airtight pipe and the small pipe, and it can be used as is without changing the conventional end structure. Unlike conventional systems, the feed pipe is not exposed, so it saves time and effort in laying the cables, and has the remarkable effect of being able to transmit large amounts of power at a low cost.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an example of a forced cable cooling line according to the present invention, Fig. 2 is a sectional view showing an example of a cable used in the cooling line of the present invention, and Fig. 3 is an explanatory diagram showing an example of a cable forced cooling line according to the present invention. FIG. 1... Cable conductor, 2... Pipe, 3... Easily vaporized liquid, 4... Small pipe, 7... Reservoir, 9
. . . gas phase portion of reservoir 7, 10 . . . liquid phase portion of reservoir 7.

Claims (1)

[Claims] 1. In a cable line in which an airtight pipe is provided inside a conductor of a cable, a liquid that easily vaporizes is flowed into the airtight pipe, and the liquid is evaporated and vaporized to forcibly cool the conductor. A small pipe is inserted through a material with high resistance, the airtight pipe and the small pipe are communicated at one end of the cable line, and at the other end, the airtight pipe is connected to the gas phase part of the reservoir provided at a higher place than the communicating end. A circulating cable forced cooling line that utilizes latent heat of vaporization and features a small pipe connected to the liquid phase. 2. The cable forced cooling line according to claim 1, wherein the small pipe has a string made of a material with high heat resistance, such as nylon or polyethylene, wound in a spiral around its outer periphery. 3. The cable forced cooling line according to claim 1 or 2, wherein the small pipe is made of a material having higher thermal resistance than copper, such as Teflon or stainless steel.