JPS6223213Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooled power cable connection.

As the capacity of power cable lines increases, various cooling methods are being studied and implemented.

For example, as shown in Fig. 1, a large-diameter water-cooled pipe 1 is installed in a tunnel, a power cable 2 is installed inside the water-cooled pipe 1, and a cooling water 3 is flowed through the water-cooled pipe 1 to connect the power cable 2. The so-called direct cooling method installed in a tunnel is one of the most effective cooling methods.

In general, a cable line necessarily has a large number of connections 4 due to transportation and installation method constraints, but there are maintenance problems, especially since the leadwork 6 between the cable sheath 2A and the connection box 5 is exposed. This connection 4 cannot be submerged in water, and therefore the power cable 2
It has been difficult to provide the connecting portion 4 with a cooling effect equivalent to that of the above.

In a conventional water-cooled power cable line, cooling is performed by covering the power cable 2 with a water-cooled tube 1 up to the edge of the connection part 4 as shown in the figure, and the connection part 4 is cooled by expecting heat flow in the longitudinal direction of the conductor. However, measures were taken to ensure sufficient current capacity. In addition, 7 is the cooling water 3 in the water cooling pipe 1 on one side of the connection part 4.
This is a bypass pipe for feeding the liquid to a water-cooled pipe (not shown) on the opposite side of the connecting part 4, bypassing this connecting part 4.

However, in such a structure, the connection part 4
Since the thermal resistance of the power cable 2 is higher than that of the power cable 2, and the heat flow in the longitudinal direction is limited, even if the power cable 2 is supercooled, the connection part 4 becomes a link and the required power transmission capacity cannot be obtained. Ta.

To improve this, as shown in FIG. A cooled power cable connection section 9 has been proposed in which the connection section 4 is cooled by passing water therethrough. In addition, in the figure, 10 is a cable conductor, 1
1 is a reinforcing insulating layer, and 12 is an insulating oil. In this case, a part of the heat flow generated from the cable conductor 10 flows in the longitudinal direction of the conductor 10, but most of it becomes a radial heat flow, and flows into the water-cooled thin tube 8 through the thermal resistance of the reinforcing insulating layer 11 and the insulating oil 12. into the cooling water 3.

However, in such a structure, the water cooling pipe 1
Therefore, the water has to be branched to each water-cooled thin tube 8, which has the disadvantage of complicating the piping. Furthermore, since water must be supplied to the thin water-cooled tube 8 rather than the thick water-cooled tube 1, there is a drawback that pressure loss is large. Furthermore,
There is a risk that cooling water may enter the insulating oil 12 through pinholes formed in, for example, welded parts of the connection box 5, and if such a situation occurs, the insulation performance of the connection part 9 will deteriorate. . Furthermore, in the case of an insulated connection part, it is necessary to cut the water-cooled thin tube 8 along the connection box 5 in the middle, which has the disadvantage that it is extremely difficult to organize the piping compactly.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooled power cable connection part that has a simple structure and can uniformly cool the outer periphery of a connection box.

The cooled power cable connection part according to the present invention has a connection box with a double pipe structure consisting of an inner tube and an outer tube, a cooling chamber is provided between the inner and outer tubes, a heat radiation part is provided outside the connection box, The inside of the heat radiating section and the cooling chamber are connected through a connecting pipe, a boiling refrigerant is sealed in the cooling chamber, the refrigerant is boiled and evaporated by the heat in the connection box, and the generated steam leads the heat to the heat radiating section. The connection part is cooled by repeating the cycle of radiating heat, returning the refrigerant to liquid, and returning the refrigerant to the cooling chamber.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 3, the cooled power cable connection section 9 of this embodiment has a double pipe structure for the connection box 5 consisting of an inner pipe 5A and an outer pipe 5B, and cooling is performed between the inner and outer pipes 5A and 5B. A chamber 13 is formed. A heat radiating section 14 having fins or the like is provided outside the junction box 5, and the inside of this heat radiating section 14 and the inside of the cooling chamber 13 are connected through a connecting pipe 15. An insulating joint 16 and an expansion joint 17 are interposed in the middle of the connecting pipe 15. A boiling refrigerant 18 having a low boiling point is sealed in the cooling chamber 13 . In this embodiment, the heat radiation section 14 is inserted into the bypass pipe 7 and is cooled by the cooling water 3 flowing through the bypass pipe 7.

In this way, according to the heat pipe principle, the boiling refrigerant 18 in the cooling chamber 13 is boiled and evaporated by the heat flow in the radial direction in the connection part 9, and the generated refrigerant vapor carries heat to the heat radiation part 14. Heat is dissipated in the section 14, and the refrigerant vapor returns to liquid and passes through the connecting pipe 15.
It is returned to the cooling chamber 13 through the. Such a cycle is repeated to cool the connecting portion 9.
In this embodiment, since the heat dissipation part 14 is inserted into the bypass pipe 7, a closed loop consisting of the bypass pipe 7-connection pipe 15-junction box 5-cable sheath 2A-water cooling pipe 1-bypass pipe 7 is formed. Since the insulating joint 16 is interposed in the middle of the connecting pipe 15, it is possible to prevent circulating current from flowing through this closed loop. In addition, an expansion joint 17 is installed in the middle of the connecting pipe 15.
Since the expansion joint 17 absorbs vibrations caused by the pulsation of the cooled water 3 in the bypass pipe 7 or vibrations of the ground, it also absorbs thermal expansion and contraction of the connecting pipe 15, etc., and this heat pipe type cooling The welded parts of the device 19 can be protected.

FIG. 4 shows a temperature distribution diagram as viewed in the longitudinal direction from the connection part (A) when the connection part is not cooled and (B) when the connection part is cooled according to the present invention. The conditions in this case are as follows.

Power cable: 275kV OF cable, 1 x 2000mm ² Distance of exposed cable between lead work and water cooling pipe: 300mm Cable current capacity: 2520A Water temperature of heat dissipation section: 20℃ Manhole temperature: 32℃ In this example In the case of an insulated connection part as shown, the connection box 5 itself is an insulating part 2 made of an insulating tube 20, etc.
1, the left and right heat pipe type cooling devices 19 are automatically separated.

As the boiling refrigerant 18, for example, Freon having good electrical insulation properties and a low boiling point is preferable, but water may also be used since the boiling point is lowered when used under reduced pressure.

As explained above, in the cooled power cable connection part according to the present invention, the connection box has a double pipe structure, a cooling chamber is provided between the inner and outer pipes, a boiling refrigerant is sealed in this cooling pipe, and the connection box A heat dissipation section is provided outside the
This heat dissipation section and the cooling chamber are connected through a connecting pipe to perform cooling using the principle of a heat pipe.
According to such a heat pipe type cooling structure, the boiling refrigerant in that part is vaporized by the heat of each part around the outer periphery of the connection part, and the heat of vaporization is taken away, and the heat dissipation part is simply maintained at a low temperature. The outer periphery of the connection part can be cooled uniformly. Furthermore, according to the present invention,
This has the advantage of simplifying the structure. Furthermore, even if the present invention is applied to an insulated connection part, there is an advantage that the cooling means can be formed simply and as compactly as possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional power cable cooling structure, FIG. 2 is a cross-sectional view of a conventional cooled power cable connection, and FIG. 3 is a cross-sectional view of a cooled power cable connection according to the present invention. FIG. 4 is a temperature distribution diagram comparing the cooling effects of the non-cooled connection section and the cooled connection section according to the present invention. 1...Water cooling pipe, 2...Power cable, 2A...
Cable sheath, 3...Cooling water, 5...Connection box,
5A...Inner pipe, 5B...Outer pipe, 6...Plumb work section, 7
... Bypass pipe, 9 ... Cooled power cable connection section, 10 ... Cable conductor, 11 ... Reinforcement insulation layer, 12 ... Insulating oil, 13 ... Cooling room, 14 ...
Heat radiation part, 15... Connection pipe, 18... Boiling refrigerant,
19... Cooling device.

Claims (1)

[Scope of utility model registration request] The junction box has a double pipe structure consisting of an inner tube and an outer tube, a cooling chamber is provided between the inner and outer tubes, a heat radiation section is provided outside the connection box, and the heat radiation section and the cooling chamber are connected by a connecting tube. 1. A refrigerated power cable connection section, characterized in that the connection section is connected in communication with the cooling chamber, and a boiling refrigerant is sealed in the cooling chamber.