JPH028406B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in gas-cooled cables.

Traditionally, gas-cooled cables are generally
A series of long external pipes are constructed by using 10-12m steel pipes and sequentially welding and connecting many of the steel pipes.
A conductor or cable core is drawn into the internal space of the external pipe, and the internal space is filled with cooling gas.

However, such a gas-cooled cable using an external pipe has the following drawbacks.

Sequentially connecting the steel pipes requires a large number of welding and connection operations, which increases the number of construction steps.

In the bends, pre-bent steel pipes had to be used.

It was necessary to take measures against thermal expansion and contraction of the conductor or cable core and of the steel pipe as the external pipe.

Since steel pipes are magnetic, losses occur due to electromagnetic induction.

When directly buried underground, steel pipes with high bending rigidity cannot respond to ground subsidence, and there is a risk that cracks may occur.

At welded joints, there is a risk that gas may leak from a welded defective portion, and it is not easy to detect and repair the gas leak. If gas leaks into the atmosphere as described above, the efficiency of cooling gas usage decreases and gas replenishment is often required. There was a risk that the sealed space inside the tunnel would be deficient in oxygen, making maintenance work difficult.

The present invention fundamentally eliminates the various drawbacks of the conventional technology described above, reduces the number of construction steps, is easy to install, and contributes to improving the characteristics of the cable during use.
Furthermore, it is an object of the present invention to provide a gas-cooled cable of this type that can reliably detect and recover gas leaks.

That is, in the gas-cooled cable of the present invention, the external pipe is made of rubber or flexible plastic that is difficult for the cooling gas to pass through, and forms a closed space that accommodates the conductor or cable core and is filled with the cooling gas. a sheath pipe formed of rubber or flexible plastic through which cooling gas is difficult to permeate and arranged on the reinforcing pipe and having an inner diameter larger than the outer diameter of the reinforcing pipe; It is composed of a plurality of spacers interposed between the reinforcing pipe and the sheath pipe and spaced apart from each other, and between the reinforcing pipe and the sheath pipe and between adjacent spacers, there are It is characterized by forming a gas leak recovery space for collecting and recovering the cooling gas that permeates from the inside to the outside.

Embodiments of the present invention will be explained in detail below with reference to FIGS. 1 and 2, which show embodiments of the present invention.

FIG. 1 shows a preferred embodiment of the gas-cooled cable of the present invention, and is an example of a pipe-type gas-cooled cable.

In the cable of this embodiment, a metal pipe 1 made of aluminum or copper for transporting a refrigerant liquid such as fluorocarbons, and a cable core 2 made of a cross-linked polyethylene power cable core or a lead oil-filled cable core are connected to a large external It is constructed by being drawn into a pipe. The metal pipe 1 for transporting the refrigerant liquid serves as a neutral grounding conductor and may carry a large current in the event of a cable ground fault.

Therefore, the external pipe includes a reinforcing pipe 3 made of rubber or flexible plastic through which cooling gas is difficult to pass, and a sheath pipe similarly formed with rubber or flexible plastic through which cooling gas is difficult to pass through. 4, and a plurality of spacers 5 are interposed between the two pipes 3 and 4 at intervals, so that the gas is It is constructed so that a leakage recovery space 6 can be obtained.

The reinforcing pipe 3 is a metal pipe 1 for transporting refrigerant liquid.
and the cable core 2 and filled with the vaporized gas of the refrigerant transported by the metal pipe 1, that is, the vaporization path where the refrigerant released from the metal pipe returns the vaporized gas to the refrigerant transportation entrance and reliquefies it. A gas cooling passage 7 is provided, and the space 7
This is an airtight wall that prevents the vaporized gas that fills the room from passing through and leaking to the outside.

On the other hand, the sheath pipe 4 is
The reinforcing pipe 3 has an inner diameter larger than the outer diameter of the reinforcing pipe 3.
are arranged coaxially on the circumference of the pipe with a spacer 5 interposed therebetween, thereby forming a gas leak recovery space 6 between the inner and outer surfaces of itself 4 and the reinforcing pipe 3. If cooling gas permeates and leaks from the reinforcing pipe 3, the wall becomes airtight to prevent further permeation and leakage into the atmosphere.

The spacer 5 is a linear body made of conductive rubber, plastic, or a flexible non-magnetic metal member, and can also serve as an electrical shield.

However, if this is not necessary, it may be made of conventional rubber or plastic materials.

According to the embodiment described above, the main body of the external pipe is composed of the reinforced pipe 3 made of flexible rubber or plastic and the sheath pipe 4, so it is a long pipe without a connecting part. This eliminates the need for multiple welded connections, which is required when using conventional short steel pipes, and also makes it easy to install as it can be wrapped in a drum as a gas cooling cable. can be done.

Furthermore, since the reinforcing pipe 3, sheath pipe 4, and spacer 5 are not made of magnetic material, there is no loss caused by electromagnetic induction, contributing to improved characteristics.

Furthermore, the reinforcing pipe 3 and the sheath pipe 4
can freely respond to its own thermal expansion and contraction and that of the cable core 2. In addition, at the bends set in the installation route, the pipe can be bent freely during installation by bending the pipe itself, and there is no need for special bent pipes or measures against ground subsidence.

In addition, according to this embodiment, a gas leak recovery space 6 is formed between the reinforcing pipe 3 and the sheath pipe 4, which are double-configured, by intermittent interposition of spacers 5, so that the gas pressure can be reduced. Even if the cooling gas that is filled under pressure in the internal space of the reinforcing pipe 3 that receives it directly passes through and leaks to the outside, the leaked cooling gas can be compensated for in the gas leak recovery space 6. This can be collected before it passes through the sheath pipe 4 and leaks out. Therefore, by recovering the gas, it is possible to detect gas leaks, and since it can be reliably recovered without leaking into the outside air, recycling this gas can increase the efficiency of gas use, and prevent repeated use of gas. Compensation is no longer necessary. Furthermore, by eliminating the leakage of cooling gas into the atmosphere as described above, when the cable is installed inside a tunnel, there is no risk of oxygen deficiency in the sealed space inside the tunnel. This is also advantageous in terms of maintenance.

Note that gas collection and recovery in the gas leak recovery space 6 can be easily performed by evacuating the space 6 and bringing it into a negative pressure state.

Furthermore, the rubber used for the reinforcing pipe 3 and the sheath pipe 4 is a chloroprene-based rubber known under the trade name neoprene, which is reinforced with fibers such as vinylon and nylon.
It can withstand atmospheric pressure and has excellent wear resistance, aging resistance, etc.

Furthermore, in the case of plastic, performance equivalent to the above can be obtained by using a material such as vinyl or polyethylene.

FIG. 2 shows another embodiment of the gas-cooled cable according to the present invention, which is an example of a gas-insulated cable (pipeline aerial cable).

A corrugated pipe 9 is provided on a conductor 8 made of split stranded wires, a spider-shaped spacer 10 is attached to the corrugated pipe by a spacer attachment ring 11, and an external pipe is provided above the corrugated pipe.

Therefore, the external pipe includes a semiconductive reinforcing pipe 12 made of semiconductive rubber or flexible semiconductive plastic that is difficult for gas to pass through;
The outer conductor 14 is made of a large number of rectangular stranded wires that are distributed and wound around the reinforcing pipe 12 and also serves as spacers, and the outer conductor is made of rubber or flexible plastic that is difficult for gas to pass through. The inner space 13 of the reinforcing pipe 12 is filled with SF ₆ gas which is insulating and also serves as a cooling agent.

The outer conductor 14 is spaced apart between the reinforcing pipe 12, which serves as an airtight wall to prevent gas from leaking to the outside, and the sheath pipe 4, which also serves as an airtight wall. In between, a gas leak recovery space 15 similar to the embodiment described above is formed.

This embodiment can also enjoy the same advantages as the embodiment shown in FIG. 1 described above.

As is clear from the above explanation, the gas-cooled cable of the present invention can reduce the number of construction steps, is easy to install, contributes to improved cable characteristics during use, and is also effective against gas leakage. The initial objective of providing a gas-cooled cable of this type that can reliably detect and recover
It can be said that it has great practical effects as it completely eliminates the drawbacks of conventional gas-cooled cables that use steel pipes.

[Brief explanation of drawings]

FIG. 1 is an explanatory cross-sectional view showing a preferred embodiment of the gas-cooled cable according to the present invention, and FIG. 2 is an explanatory cross-sectional view showing another embodiment of the gas-cooled cable according to the present invention. In the figure, 1 is a metal pipe for transporting refrigerant liquid, 2 is a cable core, 3 is a reinforcing pipe, 4 is a sheath pipe, 5 is a spacer, 6, 15
7 is a gas leak recovery space, 7 is a vaporized gas cooling passage, and 8 is a gas leak recovery space.
is a conductor, 9 is a corrugated pipe, 10 is a spider type spacer, 11 is a spacer mounting ring,
12 is a semiconductive reinforcing pipe, 13 is an SF ₆ gas filling space, and 14 is an external conductor which also serves as a spacer.

Claims (1)

[Scope of Claims] 1. In a gas-cooled cable having an external pipe, the external pipe is made of rubber or flexible plastic that is difficult for cooling gas to pass through, and is capable of accommodating and cooling the conductor or cable core. A reinforcing pipe forming a closed space filled with gas, and a sheath made of rubber or flexible plastic through which cooling gas is difficult to permeate and having an inner diameter larger than the outer diameter of the reinforcing pipe and disposed over the reinforcing pipe. It is composed of a pipe and a plurality of spacers interposed between the reinforcing pipe and the sheath pipe in a spaced manner, and between the reinforcing pipe and the sheath pipe and between adjacent spacers, the reinforcing pipe is A gas-cooled cable characterized by forming a gas leak recovery space for collecting and recovering cooling gas that permeates from the inside of the pipe to the outside. 2. The gas-cooled cable according to claim 1, wherein the spacer is made of a conductive member that also serves as an electrical shield.