JPH0472454B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a method for cooling power cables using indirect or direct conduit water cooling.

[Prior art and problems to be solved by the invention]

"Figures 1 and 2" schematically show a conventional indirect conduit water-cooled cable line. For example, 10 is a trough, and 14 is a cable inserted into the trough 10. 16 is a cooling pipe;
Water 18 circulates within the cooling pipe 16. Further, 20 is a water circulation pump, and 22 is a cooling tower. Cooled water 18 enters the cooling tube 16 through the cooling tube inlet 160, absorbs heat from the cable 14, gradually increases in temperature, and exits through the cooling tube outlet 162. A in FIG. 3 shows the temperature distribution of the water 18 in the cooling pipe 16. Naturally, the temperature at outlet 162 is the highest, and this temperature limits the power transmission capacity of the cable. Therefore, there is a proposal to attach cooling fins to the cooling pipe 16 near the outlet 162. However, this poses a problem in that it takes up a lot of space.
Note that since the temperature of the water 18 near the inlet 160 is low,
Cable 14 is cooled more than necessary. However, if the temperature of the water 18 near the inlet 160 is increased, the temperature of the water 18 at the outlet 162 will exceed the limit value, so the temperature has no choice but to be lowered.

[Means to solve the problem]

In consideration of the above points, the present invention includes the steps of arranging a heat pipe in the longitudinal direction inside the cooling pipe, starting from the refrigerant outlet side and oriented toward the refrigerant inlet side,
The heat pipe is arranged in such a way that it does not go out from the cooling pipe, and the heat pipe conducts the heat of the refrigerant near the refrigerant outlet in the cooling pipe to the side near the refrigerant inlet. This system lowers the temperature of the water in the cable and increases the power transmission capacity of the cable.

【Example】

As shown in Figures 4 and 5, by inserting the heat pipe 24 into the cooling pipe 16 over the entire length (100m to 1000m) of each cooling section, the area near the outlet 162 of the cooling pipe 16 is heated. The temperature of the water 18 is lowered. In other words, the heat pipe 2 inserted into the cooling pipe 16
4 is very long, extending from the inlet 160 to the outlet 162 of each cooling section. The number of wires is usually two, but may be three or more. Further, the heat pipe 24 may be of a normal standard type, and the closed container is made of copper, aluminum, stainless steel, etc., and the operating fluid is water, alcohol, etc.

[Effect]

The part near the outlet of the heat pipe 24 is the evaporation part 2
42. That is, like a normal heat pipe, heat is removed from the high temperature water 18 in the evaporator 242 to lower the temperature of the water 18. Then, the temperature of the working fluid inside the heat pipe 24 rises and vaporizes, and the vapor flows to near the inlet 160 where the temperature is low. The vicinity of the inlet of the heat pipe 24 operates as a condensing section 240. Then, the heat of condensation is converted into water18
released into the The temperature distribution of the water 18 in the cooling pipe 16 is shown in B and C of "Figure 3". C is a case where the size of the heat pipe 24 is large. Water 18 near exit 162
Since the temperature of the cable 14 decreases as described above, the amount of power transmitted through the cable 14 can be increased by that amount. Note that the temperature of the water 18 near the inlet 160 increases due to the release of heat from the heat pipe 24. However, as mentioned above, since this is a part where the cable 14 has conventionally been cooled more than necessary, there is no problem in cooling the cable 14 even if the temperature rises a little. In the above embodiment, the heat pipe was provided over the entire length of the water cooling section, but the heat pipe is not limited to this, and the heat pipe is provided over the entire length of the section (100 m to 1000 m) starting from the exit side of the above section and moving toward the inlet side. )
A heat pipe having a length of about 1/20 of that may be provided in the cooling water. In that case, the temperature distribution in the cooling section simply moves from B and C in Figure 3 to B' and C' in the figure. Furthermore, it goes without saying that the refrigerant is not limited to water, but may also be oil or the like. Further, in the present invention, the case where the power cable is installed in the trough has been described, but the location where the power cable is installed is not limited to the inside of the trough, and may be installed in an indirect or direct water-cooled system such as a directly buried conduit. .

【Effect of the invention】

Insert the heat pipe in the longitudinal direction inside the cooling pipe.
The heat pipe is arranged to face the refrigerant inlet side from the refrigerant outlet side as a starting point and not to go out from the cooling pipe, and the heat pipe transfers the heat of the refrigerant near the refrigerant outlet in the cooling pipe to the direction closer to the refrigerant inlet. By making it conductive, the following effects can be achieved. (1) Since the heat of the refrigerant is not released outside the cooling pipe,
There is no need to take part of the heat pipe out of the cooling pipe. Therefore, problems with electrical insulation (in the case of direct water cooling) and sealing do not occur at the heat pipe draw-out section. Construction is easy because the heat pipe is simply inserted into the cooling pipe. (2) As mentioned above, the temperature of the refrigerant is highest near its outlet, and the temperature in this small section limits the power transmission capacity of the cable; inside the cooling pipe. The heat pipe inserted in the cooling pipe conducts the heat of the refrigerant near the refrigerant outlet in the cooling pipe toward the refrigerant inlet; the temperature of the refrigerant near the outlet decreases, and the current capacity can be increased. can. (3) The refrigerant temperature near the inlet of the cooling pipe receives heat from the outlet and rises, but as a result, the refrigerant temperature approaches an average over the entire length of the cable; Since the temperature of the refrigerant will never exceed the temperature of the nearby refrigerant, there is no need to worry about reducing the current capacity.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional indirect pipe water cooling system, FIG. 2 is an explanatory diagram of a cross section of the indirect pipe water cooling system shown in FIG. FIG. 4 is an explanatory diagram of an embodiment of the invention, and FIG. 5 is an explanatory diagram of a cross section of the embodiment of the invention shown in FIG. 4. 14...Cable, 16...Cooling pipe, 18...
Water, 24...Heat pipe.

Claims (1)

[Scope of Claims] 1. When cooling the power cable by flowing a refrigerant into a cooling pipe provided inside the power cable or along the power cable, heat is generated in the longitudinal direction of the inside of the cooling pipe. Direct the pipe from the refrigerant outlet side to the refrigerant inlet side,
A method for cooling a power cable, wherein the power cable is disposed in such a manner that it does not go out from the cooling pipe, and the heat pipe conducts heat of the refrigerant near the refrigerant outlet in the cooling pipe to a direction closer to the refrigerant inlet.