JPS5845259B2 - How to cool power cables - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cooling an electric cable having a conductive hollow refrigerant passage and a space as a refrigerant passage between an insulating layer and a metal sheath.

As shown in Fig. 1, the structure of the power cable having a conductive hollow refrigerant passage is made of copper. It is made by forming a refrigerant passage 4 and an anti-corrosion layer 6 between the layer 3 and the metal sheath.

Conventionally, as a cooling method for power cables, a cooling method has been used in which a cooling medium is circulated through a dielectric cavity refrigerant passage in a conductor as an outgoing path and a refrigerant path between an insulating layer and a metal sheath as a return path.

However, with this method, the cooling medium has already absorbed a considerable amount of heat from the object to be cooled when it passes through the outbound path, so the temperature rises, and the cooling effect when the refrigerant passes through the return path is reduced. .

The present invention has been made in view of the above-mentioned drawbacks, and is characterized by making the pressure of the refrigerant in the internal cavity of the conductor higher than the pressure of the refrigerant in the space between the insulating layer and the metal sheath, and increasing the pressure of the refrigerant flowing between the two. The present invention provides a cooling method for an electric power cable, which is characterized by circulating the refrigerant in the same direction and cooling the cable by circulating a refrigerant through a cooling device outside the cable. This is to cool down the heat caused by conductor loss and dielectric loss.

To explain the method of the present invention with reference to FIG. 2, 9 is 500
10 is a refrigerant passage (for example, OF oil as a refrigerant) in the conductor of the electric cable 9;
1 is a refrigerant passage in the space between the insulating layer of the power cable 9 and the metal sheath.

Reference numerals 12 and 13 indicate the terminal ends of the power cable 9.

The power cable 9 is provided with an outlet 14 that communicates with the refrigerant passage 11 in the space between the insulating layer and the metal sheath. The desired position is where the refrigerant that has been removed joins within the cable 9, that is, near the center of the cable 9.)

The end portion 12 is provided with a refrigerant inlet 12a that communicates with the conductive hollow refrigerant passage 10 and an inlet i2b that communicates with the refrigerant passage 11 in the space between the insulating layer and the metal sheath. Entrance 13a communicating with passage 10
, and an inlet 13b communicating with the refrigerant passage 11.

The inlets 12a and 13a are respectively pipes 15a provided outside the power cable 9 for refrigerant circulation.

15b, and the inlets 12b and 13b are respectively connected to refrigerant circulation pipes 16a and 16b provided outside the power cable 9.

On the other hand, the outlet 14 may be connected to a pipe 17 for refrigerant circulation, which is also provided outside the electric cable case 9.

The pipe 17 is connected to the pipes 15a, 15b and a pipe 16 connected to the pipes 16a, 15b.
・Ru.

A normal pressure reducing valve R1 is provided in the pipe 16 system, and the refrigerant that has passed through the pressure reducing valve RV1 is divided into the pipes 16a and 16b.

A normal cooling mechanism 18 is provided in the system of pipes 17, and the cooling mechanism 18 includes a water-oil heat exchanger, a water cooler circulation pump,
Consists of pressure pump, relief valve, tank, etc.

Next, to explain the present invention in detail, the refrigerant at 40° C. and 50 atm that is sent out by the operation of the cooling mechanism 18 passes through the pipe 17 and is divided into the pipes 15a, 15b, and 16, respectively, and the refrigerant circulating through the pipe 16 is The pressure is reduced to 5 atmospheres by the pressure reducing valve RV (that is, the pressure is lower than the pressure of the refrigerant flowing through the conductor internal cavity refrigerant passage 10), and the pipes 16a, 1
6b, and these pipes 15a, 15b, 16a.

The refrigerant flowing through 16b flows into the power cable 9 through ports 12a, 12b, 13a, and 13b provided at the terminal end 12.13.

The refrigerant circulating in the refrigerant passage 10 has a higher pressure than the refrigerant circulating in the refrigerant passage 11, so it passes through the inside of the conductor and radially outward of the cable, cooling the insulation layer. However, since the electric cable case 9 is also cooled from the outside by the refrigerant circulating in the refrigerant passage 11 to ℃°C, the refrigerant coming out radially outward from the refrigerant passage 10 inside the conductor is The temperature will not rise much L
゛.

The refrigerant that has cooled the electric cable cable 9 in the above manner reaches the refrigerant outlet 14 provided in the cables 9-, h.

The refrigerant flows out into the pipe 17 at a pressure of 60°C and 1 atm, and is again cooled to 40°C and 50 atm in the cooling mechanism 18, and is increased in pressure.The above process is repeated to cool the power cable 9 until the temperature reaches 1.
.

As described above, according to the present invention, the cooling effect of the power cable can be improved by flowing a high-pressure refrigerant into the internal cavity refrigerant passage of the conductor and simultaneously flowing the refrigerant into the refrigerant passage in the space between the insulating layer and the metal sheath. By easily cooling the heat generated in the power cable due to conductor loss and dielectric loss, it is effective to reduce the temperature by ℃.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the electric cable, and FIG. 2 is a detailed explanatory diagram of the present invention. In the figure, 9 is a power cable, 10 is a refrigerant passage inside the conductor,
11 is a space between the insulating layer and the metal sheath, 18 is a cooling mechanism, and R1 is a pressure reducing valve.

Claims (1)

[Claims] 1. The pressure of the refrigerant in the differential cavity in the conductor is higher than the pressure of the refrigerant between the insulating layer and the metal sheath (so that the refrigerant in the differential cavity in the conductor can pass radially outward through the insulating layer on the outer periphery of the conductor, and A method for cooling an electric power cable, characterized in that the refrigerant flows through both cables in the same direction, and the refrigerant is circulated through a cooling device outside the cable to cool the cable.