JPS6070915A - Method of cooling power cable connection box - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of cooling a connecting portion of an electric power cable using a heat pipe.

The insulation thickness of the junction box of a high-capacity cable is thicker than that of the cable, which reduces the power transmission capacity.

To solve this problem, the following cooling method using heat pipes has been proposed.

"FIG. 1" is a schematic explanatory diagram thereof, in which reference numeral 10 indicates the entire junction box, 12 the steel pipe thereof, 14 the cable conductor, and 16 the connection sleeve. The heat pipe 20 is inserted into the oil passage 18 within the conductor 14.

In this way, the high heat inside the junction box IO is carried by the heat pipe 20 to the cable section where the temperature is lower than that, and as a result, the temperature difference between the junction section and the cable section is reduced. (Note 1).

However, this method has problems such as: 1) the cooling efficiency is not very good; 2) if the heat pipe breaks down, it is difficult to repair it;
3) There are problems such as the fact that it cannot be used for anything other than OF cables that have oil passages inside the cable conductor.

The present invention aims to provide a cooling method using a heat pipe that has good cooling efficiency and is easy to maintain.

(1) It relates to an electric cable that is indirectly cooled by a cooling pipe that circulates cold water inside the cable, (2) Between the connection box of the electric cable and the cooling pipe. are thermally connected by a heat pipe.

Note that thermally connecting the junction box and the cooling pipe with a heat pipe means that one end of the heat pipe is thermally connected to the junction box, and the other end is thermally connected to the cooling box, so that the heat is connected This means that it can be moved from the box to the cooling pipe.

Actual Example ~ Currently, indirect cooling within a trough is generally used for large-capacity underground power transmission lines. Therefore, an example of that case will be explained.

In "Figure 2", 30 is a trough, for example, FRP
Made in Japan. 32 is a cable, and 34 is a cooling pipe made of polyethylene, for example, in which cold water 36 is circulated.

In "Fig. 3", 38 indicates a connection box, and 40 indicates its steel pipe. 42 is a heat pipe. One end 44 thereof is thermally coupled to the junction box 38, and the other end 46 is thermally coupled to the cooling pipe 34, respectively. Note that the heat pipe 42 may be of a standard type using copper or aluminum as the material of the closed container, and pure water as the operating fluid.

At the joints between both ends of the heat pipe 42 and the cooling pipe 34 and the connection box 38, the thermal resistance is made to be as small as possible (this is generally true for heat pipes). For that purpose, for example, "Figure 4"
As shown in FIG.
Alternatively, the tube may be filled with rubber 52 or the like, and the outside thereof may be wrapped with a heat-shrinkable tube 54. In addition, polyethylene is used for the cooling pipe 34 as described above, but since polyethylene does not have very good thermal conductivity compared to copper, a metal joint is used in the part that contacts the heat pipe 42. can also be considered.

The same can be said of the contact portion between the heat pipe 42 and the connection box 38. In addition, in the case of the junction box 38, in addition to the method of bringing the heat pipe 42 into contact with the outside of the steel pipe 40, a method such as inserting it inside and bringing it into direct contact with the insulating oil inside the junction box may be used. You can also do it.

By doing so, the heat of the junction box 38 is very efficiently transported to the cooling pipe 34 and removed by the cold water inside the cooling pipe 34. Therefore, a local temperature rise in the junction box 38 can be suppressed very efficiently.

It should be noted that the present invention is applicable not only to the case of installation in a trough, but also to all cases of indirect cooling using the cooling pipe 34.

(1) Heat absorption is done by heat pump and cold water, so cooling efficiency is high.

(2) The Heater Eve is easy to handle and maintain.

(3) Applicable to cables without oil passages within the cable conductor.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the prior art, Fig. 2 and the following are detailed explanatory diagrams of the present invention, Fig. 2 is an explanatory diagram of the installation status of the cable 32 and cooling pipe 34 in the trough, and Fig. 3 is a cooling method. FIG. 4 is an explanatory diagram of the joint portion between the cooling pipe 34 and the heat pipe 42. 30 Nidraft 32: Cable 34: Cooling pipe 36: Cold water 38: Connection box 40: Connection steel pipe 42: Heat pipe Note 1 Matarou Kage: Iwa 1) et al.: Study of heat pipe type low thermal resistance joint, 1976 Institute of Electrical Engineers of Japan National conference collection 1
075 Patent applicant: Fujikura Electric Wire Co., Ltd. Agent: Keiji Kaihei

Claims (1)

[Claims] An electric power cable that is indirectly cooled by a cooling pipe in which wood is circulated, characterized in that a connection box of the electric power cable and the cooling pipe are thermally connected by a heat pipe. How to cool the power cable junction box.