JPS6337564B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for connecting flexible conduit aerial cables.

[Prior Art] A conduit aerial cable in which a metal pipe conductor is supported in a hollow metal sheath with an insulating spacer and the hollow metal sheath is filled with an insulating gas can increase the diameter of the conductor, and the insulating gas is It has good heat dissipation through convection, so it is used as a cable suitable for transmitting large amounts of power, but it is not flexible and cannot be transported in long lengths, so many short cables are transported and connected at the installation site. The number of connections required was extremely large, and installation required a long period of time.

In order to improve this problem, a flexible conduit aerial cable that is flexible and can be drum-wound was developed, but this is a stranded conductor or a corrugated cable containing a stranded conductor, as shown in Figure 3. An extruded insulating coating layer 21 for electric field relaxation is provided on a flexible conductor 22 made of a metal pipe conductor, and the conductor 22 is supported by an insulating spacer 24 within a flexible corrugated metal sheath 23 coated with an anticorrosive layer 26. It has a flexible structure in which an insulating gas 25 is sealed in a metal sheath.

[Problems to be solved by the invention] Since the above-mentioned flexible conduit aerial cable is flexible, it can be made into a long cable with a single transportation length of about 100 m. Later, a problem arose in that it took a long time to evacuate the entire cable line and fill it with insulating gas.

In addition, the insulation properties of gas-insulated cables are greatly degraded due to the contamination of foreign matter, but the connection parts of conventional pipeline aerial cables as mentioned above are not airtightly separated from the cable part and the connection part. There is a risk that foreign matter may get mixed into the cable during connection work, and there is a problem in that connection work requires great care and a high degree of skill.

SUMMARY OF THE INVENTION Therefore, the present invention provides a method for connecting a flexible conduit aerial cable, which prevents foreign matter from entering the cable and facilitates connection work.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a structure in which a bottomed metal tube is fitted to the connection terminal of a conductor of a flexible conduit aerial cable, and a bottomed metal tube is fitted onto the bottomed metal tube. A gas-stop insulating spacer is airtightly fixed to the metal tube with a connector and a fixing metal fitting welded to the corrugated metal sheath.
The inside of this cable is evacuated and filled with insulating gas to form a cable connection end, and at the cable installation and connection site, the cable connection ends of each cable to be connected are matched and fitted to each conductor terminal. Connect the bottomed metal pipe parts with connecting tubes to form a conductor connection part, cover the outer periphery of this conductor connection part with a connection box with a connector, and connect both ends of the box to the outer periphery of each gas stop insulating spacer. The flexible conduit aerial cable is connected by a method of airtightly welding it to a fixing metal fitting, evacuating the inside of this connection box, and filling it with insulating gas to form a cable connection part.

[Function] The bottomed metal tube is fitted onto the connection terminal of the conductor at the cable connection end to seal the conductor terminal, and the gas stop insulating spacer closes the opening at the terminal of the corrugated metal sheath. At the same time, the conductor is supported in the center of the corrugated metal sheath, and the connector attached to the metal tube is able to draw a vacuum inside the cable and fill it with insulating gas. Then, the cable connection end portion filled with insulating gas and sealed is manufactured at a cable manufacturing factory and shipped.

At the cable installation and connection site, the cable connection ends that are shipped with the ends sealed in advance are used as they are, and the conductors are connected by butting each cable connection end against each other, and the conductor connections are connected. The connection box is airtightly surrounded by a connection box, and only the inside of the connection box of the connection part where the cable part and the connection part are airtightly separated is evacuated from the connector and filled with insulating gas. In this way, the connection of the flexible conduit aerial cable is completed.

[Examples] Examples of the present invention will be described below with reference to the drawings. Figure 1 shows the state of the cable connection end that is manufactured in advance at a factory and shipped when connecting a flexible conduit aerial cable by the method of the present invention, and Figure 2 shows the state of the cable connection end that is manufactured in advance at a factory and shipped. This figure shows the state in which the ends are connected at the cable installation site.

First, the connecting end of a flexible conduit aerial cable manufactured in a factory by the method of the present invention and shipped is configured as shown in the first figure. In the figure, 1 is the cable conductor, 2 is the insulation coating on the conductor 1, and 5 is the outer corrugated metal sheath.The insulation coating 2 on the conductor 1 at the connection terminal of the cable is peeled off to expose the conductor connection terminal. I'll let it happen.

A bottomed metal pipe 3 and a gas-stop insulating spacer 4 are attached to the connection terminal portion of the cable where the conductor connection terminal is exposed.

The bottomed metal tube 3 has an open rear end and a bottom 3a at the tip.
The inner diameter of the rear end opening is formed to a diameter into which the terminal end of the conductor 1 is fitted, and this is fitted into the connecting terminal of the conductor 1. Further, the gas stop insulating spacer 4 supports the conductor 1 at the center of the corrugated metal sheath 5 by inserting the bottomed metal tube 3 into the center hole of the insulating disk, and also supports the conductor 1 at the center of the corrugated metal sheath 5. This gas-stop insulating spacer 4 is used to close the opening between the metal sheath 5 and the terminal end of the metal sheath 5 to prevent the insulating gas in the cable from coming out from the opening.
The center hole is fitted into the bottomed metal tube 3, and the tube is airtightly fixed with an adhesive or the like.

A metal tube 6 is welded to the end of the corrugated metal sheath 5. Note that the end of the metal sheath 5 is formed into a pipe-shaped portion 8 so that a metal tube 6 can be easily welded, and a connector 9 is attached to the metal tube 6 for both the purpose of drawing a vacuum and filling in an insulating gas.

The outer peripheral edge of the gas stop insulating spacer 4 is sandwiched between the tip of the metal tube 6 with the connector 9 and the fixing fitting 7 together with the packing 14, and the fixing fitting 7
is welded to the tip of the metal tube 6 to airtightly fix the outer peripheral edge of the gas stop insulating spacer 4.

As described above, the end of the corrugated metal sheath 5 and the end of the conductor 1 are hermetically sealed with the bottomed metal tube 3, the gas-stop insulating spacer 4, and the metal tube 6, and the inside of the cable is evacuated from the connector 9. The cable connection end is filled with insulating gas 15 and shipped from the factory to the cable installation site.

Next, at the installation site of the flexible conduit aerial cable, the cable connection end is connected to the second
The connections are made as shown in the figure. First, a metal cylindrical connection box 11 is inserted and shifted over the cables on the cable connection end side of one of the two cables to be connected. The inner diameter of this connection box 11 is equal to the outer diameter of the fixing fitting 7, and its length is approximately equal to the distance between the two gas stop insulating spacers 4, 4 when both cable connection ends are connected. Connector 1 that is the same and can be used for both vacuuming and insulating gas filling
4 and 14 are attached.

The connecting ends of the respective cables to be connected are butted against each other, and the bottoms 3a, 3a of the tips of the bottomed metal tubes 3, 3 fitted on the terminals of both conductors 1, 1 are butted, and the butted A connecting tube 10 of a sleeve is placed over both bottomed metal tubes 3, 3, and the connecting tube 10 is compressed to connect each of the conductors 1, 1 fitted to the terminals of the respective conductors 1, 1 at the ends for connecting both cables. The bottomed metal tubes 3, 3 are connected to form a conductor connection portion.

Then a connection box 11 with a connector 14 fitted onto the cable connection end on one side.
is drawn onto the conductor connection portion, and both ends of the box are hermetically welded to the fixing fittings 7 on the outer periphery of each gas-stop insulating spacer 4, 4 at both cable connection ends.

The inside of the connection box 11, which is airtightly installed as described above, is evacuated from the connectors 14 and filled with insulating gas. Note that, if necessary, one or both of the connectors 14, 14 are communicated with the connector 9 at the cable connection end via the communication pipe 13.
16 is an insulating tape wrapping layer. In this way, both cable connection ends are connected to form a cable connection section and the connection work is completed.

In the method for connecting a flexible conduit aerial cable of the present invention, as described above, first, in a factory where a flexible conduit aerial cable is manufactured, the cable connecting end is connected in advance to a bottomed metal tube 3 and a gas-stop insulating spacer 4. The cable is manufactured in a sealed manner and shipped, and then the sealed and shipped cable connection end is connected at the cable installation and connection site, thereby making it possible to connect the cable part and the connection part. The connection work is performed after they are separated airtight.

[Effects of the Invention] As described above, the present invention has a bottomed metal tube and a gas-stop insulating spacer airtightly attached to the connection end of the cable to be connected, and the cable is evacuated and filled with insulating gas to close the end. Since the sealed cable connection end is manufactured in advance in a pre-equipped factory, there is no risk of foreign matter getting into the cable, and the connection work at the cable installation and connection site is done to ensure that the cable part and the connection part are airtight. Since the cables are separated, foreign matter does not get into the cable during connection work, and vacuuming only needs to be done inside the connection box, making connection work extremely easy.
This can greatly reduce work time.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the connecting end of a cable in the method of the present invention, FIG. 2 is a sectional view of the cable connected state, and FIG. 3 is a sectional view of a conventional example. 1: Conductor, 3: Bottomed metal tube, 4: Gas stop insulating spacer, 5: Corrugated metal sheath, 6: Metal tube,
7: Fixing metal fittings, 9: Connector, 10: Connection pipe, 1
1: Connection box, 12: Connector.

Claims (1)

[Claims] 1. A metal tube with a bottom is fitted to the connection terminal of the cable conductor, a gas-stop insulating spacer is airtightly fixed on the metal tube, and a metal tube with a connector and fixing metal fittings are welded to the end of the corrugated metal sheath. The outer periphery of the gas stop insulating spacer is airtightly fixed, the inside of this cable is evacuated and filled with insulating gas to create a cable connection end, and then at the cable installation and connection site, each cable to be connected is A conductor connection section is formed by butting the cable connection ends together and connecting the respective bottomed metal tubes with a connection tube, and a connection box with a connector is placed over the outer periphery of the conductor connection section, and both ends of the box are A method for connecting a cable in a flexible conduit, which comprises airtightly welding a gas-stop insulating spacer to a fixing fitting on the outer periphery, evacuating the inside of this connection box, and filling it with insulating gas to form a cable connection part.