JPS5850496B2 - Cooling device for conductor internal water cooling cable - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for a conductor-internal water-cooled cable that cools the inside of a cable conductor with cooling water.

With the recent increase in power demand, large-capacity power transmission has become necessary.

As one method, a method of forcibly cooling the cable is being considered.

Forced cooling methods for cables include a method in which a cooling pipe is laid outside the cable (indirect cooling method), a method in which refrigerant is flowed directly around the cable anticorrosion layer (direct cooling method), and a method in which the inside of the cable conductor is directly cooled (conductor internal cooling method)
etc.

Of these, the method that allows for the largest capacity transmission is the conductor internal cooling method.

For the conductor internal cooling method, the characteristics of the refrigerant are such that the pressure loss in the longitudinal direction is kept small, the viscosity is low in order to increase the distance between cooling stations, and the specific heat of the residue is large. The formula is used.

This equation (1) RL represents the ratio of the lengths that can be cooled when the same power transmission current is passed through the cables that are cooled with the first and second refrigerants, respectively.

The coolable length is expressed by the following formula.

:Cable heat generation (W/m) :Refrigerant viscosity coefficient (NS/m') :Refrigerant pressure loss (bar) :Refrigerant temperature rise (°C) ρ :Refrigerant density (ky/m') CP : Specific heat of refrigerant (J/kg・℃) d: Pipe diameter of refrigerant (m) For formula (1), water is used as the first refrigerant, and when this water is set as 1, the ratio RL of each refrigerant is The result will be as shown in the table below.

Therefore, from the standpoint of cooling performance, it can be seen that water is most suitable as a refrigerant.

However, when water is used as a refrigerant, since water has conductivity, measures for electrical insulation are unnecessary in the cooling device.

FIG. 1 shows an example of a conventional cooling device for a conductor-internal water-cooled cable that takes such measures.

That is, this cooling device flows toward the terminal end 2 of the conductor-internal water-cooled cable 1 through a cable conductor (not shown) in this terminal end 2, which is the high potential section H? In order to guide the cooling water to the ground-based pump 3 and heat exchanger 4, which are low-potential parts, a cooling water return insulated pipe 6, etc. is connected to the lead-out metal pipe 5 connected to the terminal of the cable conductor, and this cooling water is It is connected to the pump 3 side via a return pipe 6 and the like.

As described above, the conventional cooling device has the disadvantage that it is troublesome to guide the cooling water from the high potential section H to the low potential section L (earth potential).

If the flow rate of cooling water decreases, the cooling water will boil,
There is a risk that the cooling water return pipe 6, etc. may explode.

SUMMARY OF THE INVENTION An object of the present invention is to provide a cooling device for a water-cooled cable inside a conductor, which can solve the problem of cooling the cable by flowing water, which is the most suitable refrigerant in terms of cooling performance, into a water channel inside the conductor.

Hereinafter, specific examples of the present invention will be described in detail with reference to the drawings.

2 and 3 show an example in which the present invention is applied to an internal conductor water-cooled cable 1 having both an outgoing channel 8 and a returning channel 9 in the cable conductor 7 as shown in FIG. 4 or 5. This is what is shown.

In this embodiment, a cooling water circulation pump 10, which is a means for forced circulation of cooling water for cooling the conductor, is provided on the terminal end 2 side of the conductor internal water-cooled cable 1, that is, on the high potential part H side, and a cooling water circulation pump 10, which is a forced circulation means for cooling water for cooling the conductor, and a cooling water for cooling the cooling water. A metal pipe 1 in which a heat exchanger 11 is installed and connects a return waterway 9 and an outgoing waterway 8 of the cable 1 outside the cable 1.
2, this cooling water circulation pump 10 and a heat radiation pipe 11a of a cooling water heat exchanger 11 are connected in series.

As the cooling water circulation pump 10, in this embodiment, a fluid-driven pump that does not require a power source is particularly used.

Oil is used as a refrigerant to exchange heat with the cooling water in the cooled water heat exchanger 11.

Since oil generally has electrical insulation properties, there is no problem in terms of electrical insulation between the high potential part H side and the low potential part side.

In order to circulate oil as an insulating refrigerant, that is, cooling oil, between the high potential part H side and the low potential part side, a cooling oil circulation path 1 is provided.
3 is formed of an insulated pipe, and on the high potential part H side, a cooling water circulation pump 10 and a cooling water heat exchanger 11 are connected in series to this cooling oil circulation path 13, and the cooling water circulation pump 10 is operated by the circulating cooling oil. , and exchange heat with the cooling water in the cooling water heat exchanger 11. On the other hand, on the low potential side, a cooling oil circulation pump 14 and a cooling oil heat exchanger 15 are connected in series to this cooling oil circulation path 13. When connected, the pump 14 is used to forcefully circulate the cooling oil, and the heat exchanger 15 is used to radiate heat from the cooling oil.

If the cooling water is cooled by heat exchange with the cooling oil on the high potential part H side in this way, there is no need to lead the conductive cooling water to the low potential part side, and therefore the cooling water return pipe is etc. will no longer be needed.

Additionally, the refrigerant that circulates between the high potential part H side and the low potential part side in order to dissipate heat from the cooling water is a cooling oil having electrical insulation properties, so there is no problem in terms of electrical insulation properties.

Furthermore, since a fluid-driven pump is used as the cooling water circulation pump 10 in this embodiment, there is no need for expensive power supply equipment designed to prevent dielectric breakdown at high potential parts.

FIG. 6 shows the present invention applied when two in-phase water-cooled cables 1 and 1' having either an outgoing channel 8 or a returning channel 9 are installed in the cable conductor 7 as shown in FIG. 7. This is an example.

When only one water channel is provided in the cable conductor T in this manner, the effective refrigerant passage diameter can be increased, and cooling over a longer distance becomes possible.

Of course, the cooling water also includes water in which solutes have been dissolved to increase the heat capacity.

Further, in the above embodiment, a fluid-driven pump is used as the cooling water circulation pump 10, but the present invention is not limited to this, and an electric pump can also be used.

As explained above, in the cooling device for a water-cooled cable inside a conductor according to the present invention, water, which is the most suitable refrigerant from the standpoint of cooling performance, is poured into the water channel inside the conductor to cool the cable. Compared to cooling with oil, the cooling efficiency is higher, the cable can be efficiently cooled, and the problems associated with flowing the cooling water into the water channels inside the conductor can also be solved.

That is, in the present invention, a cooling water circulation pump and a cooling water heat exchanger are installed on the high potential part side, and the cooling water is cooled by exchanging heat with cooling oil in this cooling water heat exchanger. There is no need to lead water to the low potential part side, a cooling water return pipe, etc. can be omitted, and the risk of explosion can be avoided.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional cooling device, FIG. 2 is a system diagram of an embodiment of the cooling device for a conductor internal water-cooled cable according to the present invention, and FIG. 3 is a more specific diagram of the device shown in FIG. 2. 4 and 5 are cross-sectional views showing examples of two types of conductor internal structures of an internal water-cooled cable having two water channels inside the conductor, and FIG. A system diagram of another embodiment of the device, FIG. 7 is a sectional view showing an example of the internal structure of a conductor of an internal water-cooled cable having one water channel inside the conductor. Ll'...Conductor internal water cooling cable, H...High potential part,
L...Low potential part, 7...Cable conductor, 8, 9...
- Water channel, 10... Cooling water circulation pump, 11... Cooling water heat exchanger, 13... Cooling oil circulation path, 14... Cooling oil circulation pump, 15... Cooling oil heat exchanger.

Claims (1)

[Claims] 1. A cooling device for an internal water-cooled cable that cools the conductor by flowing cooling water through a water channel inside the conductor, which includes a cooling water circulation pump for forced circulation of the cooling water and a cooling water circulation pump for cooling the cooling water by exchanging heat with insulating oil. A cooling water heat exchanger is installed on the high potential part side of the conductor internal water cooling cable, and a circulation path for the cooling oil that passes through the cooling water heat exchanger and exchanges heat with the cooling water is connected to the high potential part. a cooling oil circulation pump that is formed astride between the low potential part and tightly circulates the cooling oil in the middle of the circulation path toward the low potential part; and a cooling oil heat exchanger that cools the cooling oil. 1. A cooling device for a water-cooled cable inside a conductor, characterized in that a conductor is provided with a water-cooled cable.