JPS582121Y2 - Insulated internally cooled cable track - Google Patents

Description

[Detailed Description of the Invention] The invention relates to an improvement in an internally cooled cable line for cooling a laid cable from the inside by passing a refrigerant inside the conductor of the cable.

In conventional internal cooling cable lines, the refrigerant passage provided inside the cable conductor and the return pipe are connected between the stop joints of the cable to form a refrigerant circulation path, and a heat exchanger is installed in the middle of the return pipe. The heat generated from the cable is removed by cooling the refrigerant through the cable, but the refrigerant circulating within the cable is cooled by a heat exchanger and then passing through the cable (because it is gradually heated and the temperature rises). 1) The temperature of the cable has a gradient in the longitudinal direction and reaches its highest temperature near the refrigerant outlet of the cable, which is an obstacle to increasing the current capacity.

In particular, in a cable line laid in a tunnel, the temperature of the cable increases abnormally due to the effects of heat radiated from the cable and heat radiated from a return pipe through which high-temperature refrigerant flows.

For this reason, it was necessary to take measures such as installing air cooling devices to cool the inside of the tunnel in each certain cooling effective section.

The present invention has been developed in view of the above points, and an embodiment thereof will be described below with reference to the drawings. is provided with a heat insulating layer 6.

The heat insulating layer 6 is not limited to the outer periphery of the sheath 5, but may be provided between the conductor 2 and the cable insulator 4 or between the insulator 4 and the sheath 5.

7 is a stop joint, 8 is a return pipe with a heat insulating layer 9 on its outer periphery, 10 is a pump connected to the return pipe, 11 is a heat exchanger installed in the return pipe, and as shown in Figure 2, the cable The refrigerant passage 3 in the conductor and the return pipe 8 are connected at the stop joint 7.7 to form a refrigerant circulation path for each stop joint section, and the refrigerant is cooled by the heat exchanger 11 provided in the return pipe 8. The refrigerant is circulated by the pump 10 to cool the cable.

With this structure, the refrigerant heated while passing through the refrigerant passage 3 in the cable conductor passes from the stop joint 7 on one side, through the return pipe 8, and is cooled in the heat exchanger 11 in the direction of the arrow. The cable is cooled by passing through the stop joint 7 and into the refrigerant passage 3 within the cable conductor.

However, in this case, since the installed cable 1 and return pipe 8 are provided with insulation layers 6 and 9, the influence of heat radiation on other cables or the thermal influence of ambient temperature rise is significantly reduced, and the cooling effect of the cable is extremely high. becomes good.

Next, I will explain a specific example of this inconvenience (cross-sectional area 2000u
f, oil passage diameter 50mmφ, 275Kv length 500m O
F cable (cable 1 with a heat insulating layer of 207 Lrft thick polyethylene foam and an inner diameter of 50 Lrft)
This is the same as the proposed tatami cable line constructed by connecting a return pipe 8 with a copper pipe of m1φ (with a heat insulating layer of 20 mm thick foamed polyethylene) as shown in Figure 3. The conditions are: conventional cable line without heat insulation layer, outside temperature 20℃, circulating cooling oil amount 2000 ec/s
2000A~60 for each cable under EC conditions
The refrigerant temperature at measurement points A, B, C, D, and E was actually measured by passing a current of 00 A, and the results are shown in the following table.

According to the present invention, by providing a heat insulating layer around the cable and return pipe as described above, thermal interference between the cables and between the return pipe and the cable due to heat dissipation from the cable and return pipe is reduced. Thermal effects caused by temperature changes f are significantly reduced, the cooling effect of the cable is improved, and the current carrying capacity can be increased.

In addition, if the cable is installed inside a tunnel, there is no need to take measures such as defining effective cooling sections and installing a wind cooling device in each section, which is the case with conventional methods, which can greatly reduce construction costs. There are advantages.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the cooling cable and return pipe of the present invention, and FIGS. 2 and 3 are explanatory diagrams showing an embodiment of the present invention. 1: cable, 2: conductor, 3: refrigerant passage, 4: insulator,
5: Sheath, 6: Heat insulation layer, γ-nis top joint, 8
: Return pipe, 9: Heat insulation layer, 10: Pump, 1: Heat exchanger.

Claims (1)

[Scope of utility model registration request] The refrigerant passage in the cable and the return pipe provided with a heat exchanger form a refrigerant circulation path for each stop joint section, and the refrigerant passage in the cable conductor (the refrigerant passage in the cable line where the refrigerant is circulated) A thermally insulated internally cooled cable line characterized in that a heat insulating layer is provided on the outer periphery of the internal conductor of the installed cable and on the outer periphery of the return pipe.