JP5697018B2 - Assembly method of power cable end connection - Google Patents

Description

  The present invention relates to a method for assembling a power cable terminal connection portion.

2. Description of the Related Art Conventionally, an oil-immersed termination connection portion in which a soot tube is filled with oil is known as a power cable termination connection portion. In this system, if oil leakage occurs, the surrounding environment may be contaminated. Therefore, in recent years, a completely dry terminal connection portion that does not use oil as an insulating filler has been developed.
As a completely dry terminal connection part, for example, a terminal connection part in which a gel-like insulator such as silicone gel which is an insulating resin instead of oil is filled in a soot tube is known (for example, see Patent Document 1). The raw material for the gel-like insulator (referred to as “gel raw material” in the present application) is in a liquid state, but loses fluidity when it is solidified into a gel. According to the terminal connection portion filled with such a gel insulator, the risk of environmental pollution as described above can be avoided.
In the terminal connection portion to which the above method is applied, when injecting the gel raw material into the tub tube, for example, a dedicated injection device 300 (see, for example, Non-Patent Document 1) as shown in FIG. 6 is used. The injection device 300 includes a static mixer 301 and a pump 302. The main raw material A and the curing agent B, which are gel raw materials, are supplied to the static mixer 301 via the pump 302, and after stirring with the static mixer 301, the mixed gel raw material is injected from the lower part of the tub tube 400 to thereby obtain the gel raw material. Air is prevented from being mixed in.

Japanese Utility Model Publication No. 6-80338 Jicable’03A6.4. “New dry outdoor terminations for HV extruded cables”

If air bubbles are present in the gel-like insulator, discharge may occur in the air bubble portion, which adversely affects the insulation performance. Therefore, the injection device 300 prevents air from being mixed into the gel material.
However, the present inventors have conducted various experiments, and when the gel raw material is injected, air may remain at the interface with the inner peripheral surface of the soot tube and the outer peripheral surface of the power cable. It has been found that bubbles may remain in the gel insulator.
An object of this invention is to provide the assembly method of the electric power cable termination | terminus connection part which can prevent such bubble remaining more reliably.

In order to solve the above problems, one aspect of the method for assembling the power cable terminal connection portion of the present invention is:
In the method of assembling a power cable terminal connecting portion in which a gel-like insulator is filled in a soot tube into which an end portion of a power cable is inserted , the entire surface that contacts the gel-like insulator (hereinafter referred to as “contact surface”) is preliminarily formed. The gel material is injected into the tubule after being wetted with a fluid.

As described above, before the gel raw material is injected into the tub tube, the contact surface is wetted with a fluid in advance, thereby preventing bubbles from remaining in the gel-like insulator.
The reason is not clear, but we consider that this is because the wettability between the gel material injected into the tubule and the contact surface is improved.

  As a preferable method for wetting with a fluid, there is a method in which the fluid is once injected into the soot tube and then discharged.

  By once injecting / extracting the fluid into the soot tube, the inner peripheral surface of the soot tube and the outer peripheral surface of the power cable are wetted, so that both peripheral surfaces can be wetted together without being wetted individually. Thereby, the work process can be made efficient.

  Furthermore, as a preferable method for wetting with a fluid, there is a method of applying or spraying the fluid.

  The method of applying or spraying fluid has an advantage that the amount of fluid used can be reduced.

  Examples of the contact surface include an inner peripheral surface of a soot tube and an outer peripheral surface of a power cable. The ease with which bubbles remain is different depending on the ease of familiarity between the surface material and the gel material and the angle of the surface, so it is only necessary to wet the portion where bubbles are likely to remain. It is not always necessary to wet all contact surfaces with fluid.

Various fluids can be used as the fluid as long as they do not adversely affect the insulation performance of the gel-like insulator. In general, an insulating oil such as silicone oil is suitable. It is also possible to use a part of the raw material for the gel-like insulator as the “fluid”.
When the gel-like insulator is a silicone gel, silicone oil is suitable as the “fluid”.

  Further, when the gel-like insulator is a mixture of silicone rubber and silicone oil, silicone oil is suitable as the “fluid”.

  According to the present invention, bubbles in the gel insulator can be reduced.

It is sectional drawing which shows schematic structure of the power cable termination | terminus connection part which concerns on this embodiment. It is explanatory drawing which shows each process of the assembly method of the power cable termination | terminus connection part which concerns on this embodiment. It is explanatory drawing which shows the modification of the assembly method of the power cable termination | terminus connection part of FIG. It is a perspective view which shows schematic structure of the coating device used for the assembly method of the electric power cable termination | terminus connection part which concerns on this embodiment. It is a fragmentary sectional view which shows the modification of the power cable termination | terminus connection part which concerns on this embodiment. It is explanatory drawing which shows an example of the exclusive injection apparatus used conventionally.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
Before describing the method for assembling the power cable terminal connecting portion according to the present invention, the power cable terminal connecting portion 1 assembled by the assembling method will be described.

First, the power cable terminal connection unit 1 will be described. FIG. 1 is a cross-sectional view illustrating a schematic configuration of a power cable terminal connection portion 1 according to the present embodiment. In FIG. 1, reference numeral 2 denotes a power cable insulated with rubber or plastic. The power cable 2 is stripped, and the external semiconductive layer 3, the insulating layer 4, and the conductor 5 are sequentially exposed. Reference numeral 6 denotes a rubber block mounted on the outer periphery of the power cable 2 from the outer semiconductive layer 3 to the insulating layer 4. The rubber block 6 is composed of a semiconductive rubber part 61 for electric field relaxation and an insulating rubber part 62, and is in close contact with the outer peripheral surface of the cable core by a contraction force due to being expanded in diameter from the cable 2. 7 is a conductor lead bar that is compression-connected to the conductor 5, 8 is a saddle tube, 9 is an upper fitting that closes the upper opening of the saddle tube 8, 10 is a lower fitting that closes the lower opening of the saddle tube 8, and 11 is integrated with the lower fitting 10. The cable holding tube 12a is a gel insulator filled in the tub tube 8, and 13 is a gel stopper for preventing the gel raw material 12 from flowing out.

The soot tube 8 is formed with a number of pleats by covering a cylindrical body made of, for example, FRP with rubber such as silicone rubber.
The lower metal fitting 10 has an open / close type communication port 101 that allows the internal space of the soot tube 8 to communicate with the outside.

The gel insulator 12a is formed of a silicone gel. As a raw material of the silicone gel, for example, a silicone gel such as ELASTOSIL (registered trademark) RT601 manufactured by Asahi Kasei Wacker Silicone Co., Ltd. or DY35-700A / B manufactured by Toray Dow Corning Co., Ltd. can be used.
We are also examining the formation of the gel-like insulator 12a with a gel formed by mixing an addition reaction type silicone rubber raw material and silicone oil. In this case, the mixing ratio is preferably about 1 for silicone rubber and about 9 for silicone oil.
In this case, the silicone oil used to wet the inner surface of the soot tube 8 and the outer surface of the power cable 2 can be used as a raw material for the gel, and the silicone oil can be used effectively.
The gel insulator 12a can also be formed of urethane rubber such as EF243 manufactured by Daiichi Kogyo Seiyaku Co., Ltd. or KU7008 manufactured by Hitachi Chemical Co., Ltd.

Next, a method for assembling the power cable terminal connection portion 1 of this embodiment will be described.
First, the end of the power cable 2 is cut off to expose the conductor 5, and the conductor lead bar 7 is connected to the conductor 5 by compression or the like. Next, the lower metal fitting 10 is attached to the power cable 2, and then the rubber block 6 is attached to a predetermined position (cable core). When the alignment of the rubber block 6 is completed, the power cable 2 is inserted into the soot tube 8, or the soot tube 8 is placed on the power cable 2, and the lower metal fitting 10 is attached to the soot tube 8. Thereafter, the gel stopper 13 is formed while performing anticorrosion treatment between the cable holding tube 11 of the lower metal fitting 10 and the power cable 2.

  Then, as shown in FIG. 2A, only the silicone oil 14 is injected into the soot tube 8 from the upper opening. The silicone oil 14 used at this time preferably has the same or similar molecular structure as one of the gel raw materials used to form the gel insulator 12a.

  When the silicone oil 14 is filled to a predetermined position, as shown in FIG. 2B, the discharge hose 102 is attached to the communication port 101 of the lower metal fitting 10, and then the communication port 101 is opened. Thereby, the silicone oil 14 in the soot tube 8 is discharged to the outside through the communication port 101 and the discharge hose 102. After the discharge, the inner peripheral surface 81 of the soot tube 8, the outer peripheral surface 21 of the power cable 2, and the outer surface of the rubber block 6 are wetted by the silicone oil 14. In addition, after discharge | emission, the discharge hose 102 is removed from the communication port 101, and the communication port 101 is made into a closed state.

  Then, as shown in FIG. 2 (c), the base material that is the gel raw material 12, a curing agent, and in some cases, silicone oil is added and the mixture stirred and mixed with a hand mixer or the like is injected from above the funnel 8 with the funnel 15. At this time, the silicone oil 14 remaining on the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2 in advance is mixed with the gel raw material 12. After filling the gel material 12 to a predetermined position and filling the inside of the tub tube 8, the injection of the gel material 12 is stopped, and the upper metal fitting 9 is attached to the tub tube 8 as shown in FIG. Thereby, the assembly of the power cable terminal connection portion 1 is completed.

  As described above, according to the present embodiment, before the gel raw material 12 is injected into the soot tube 8, the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2 are previously wetted with the silicone oil 14. The wettability between the peripheral surfaces 81 and 21 and the gel raw material 12 can be improved and the remaining of the bubbles can be suppressed.

  In addition, once the silicone oil 14 is injected / discharged into the soot tube 8, the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2 can be wetted. That is, the peripheral surfaces 81 and 21 can be wetted together without being wetted individually. Thereby, the work process can be made efficient.

(Embodiment 2)
The process of wetting the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2 with the silicone oil 14 can be performed separately by coating or spraying. This will be specifically described with reference to FIG.
First, the end of the power cable 2 is cut off to expose the conductor 5, and the conductor lead bar 7 is connected to the conductor 5 by compression or the like. Next, the rubber block 6 is attached to the power cable 2 at a predetermined position (cable core). When the alignment of the rubber block 6 is completed, as shown in FIG. 3A, the silicone oil 14 is sprayed onto the power cable 2 and the rubber block 6 by the sprayer 30, or the silicone oil is applied with a cloth, a brush or the like. The power cable 2 and the outer peripheral surface 21 of the rubber block 6 are wetted with silicone oil.
At this time, the usage amount of the silicone oil 14 may be reduced by laying or tilting the tub tube 8 sideways.
On the other hand, in the soot tube 8, as shown in FIG. 3 (b), the lower opening of the soot tube 8 is temporarily covered and then the silicone oil 14 is poured to wet the inner peripheral surface 81 with the silicone oil 14.

  After the outer peripheral surface 21 of the power cable 2 and the inner peripheral surface 81 of the soot tube 8 are wetted with the silicone oil 14, the power cable 2 is inserted into the soot tube 8 or the soot tube on the power cable 2 as shown in FIG. 8 and attach the lower metal fitting 10 to the soot tube 8. After this attachment, the gel stopper 13 is formed while performing anticorrosion treatment between the cable holding tube 11 of the lower metal fitting 10 and the power cable 2.

  Then, as shown in FIG. 3 (d), a mixture obtained by stirring and mixing the main ingredient, which is the gel raw material 12, and the curing agent with a hand mixer or the like is injected from above the tub tube 8 by the funnel 15. After filling the gel material 12 to a predetermined position and filling the inside of the tub tube 8, the injection of the gel material 12 is stopped, and the upper metal fitting 9 is attached to the tub tube 8 as shown in FIG. Thereby, the assembly of the power cable terminal connection portion 1 is completed.

  As described above, if the silicone oil 14 is applied or sprayed to wet the inner circumferential surface 81 of the soot tube 8 and the outer circumferential surface 21 of the power cable 2, the amount of silicone oil 14 used can be suppressed. .

(Embodiment 3)
In addition, it is also possible to wet the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2 together with the silicone oil 14 by using a dedicated coating device. FIG. 4 is a perspective view showing an example of a coating apparatus. The coating apparatus 200 of FIG. 4 includes an annular oil spray pipe 201 having a flow path for silicone oil 14 therein, and a support pipe 202 attached to the oil spray pipe 201.
The oil spray pipe 201 has a large number of spray holes 203 for spraying the silicone oil 14. Among these many spray holes 203, the spray hole 203 a formed inside the oil spray pipe 201 is a hole for wetting the outer peripheral surface 21 of the power cable 2, and the spray hole formed outside the oil spray pipe 201. The hole 203 b is a hole for wetting the inner peripheral surface 81 of the soot tube 8.

  On the other hand, the support tube 202 is hollow, and the hollow portion 202 a serves as a flow path for the silicone oil 14. That is, the silicone oil 14 injected into the support tube 202 is sprayed from each spray hole 203 through the flow path in the oil spray tube 201.

  At the time of application of the silicone oil 14, the oil spray pipe 201 is disposed in the soot pipe 8 and is moved up and down while injecting the silicone oil 14 into the support pipe 202. It applies to the inner peripheral surface 81 of the soot tube 8 and the outer peripheral surface 21 of the power cable 2.

(Embodiment 4)
Although the assembly method according to the present invention has been described by exemplifying the so-called “epoch seat-less” type power cable terminal connection portion 1 in which the rubber block 6 is exposed in the first embodiment, the power cable terminal connection portion having an epoxy seat is described. It is also possible to apply the assembly method according to the present invention.

Hereinafter, the power cable terminal connection portion 1A having an epoxy seat will be described with reference to FIG. In FIG. 5, 2a is a power cable insulated with rubber or plastic. The power cable 2a is stripped, and the external semiconductive layer 3a, the insulating layer 4a, and the conductor 5a are sequentially exposed. 6a is a rubber block mounted from the outer semiconductive layer 3a to the insulating layer 4a of the power cable 2a. 7a is a conductor lead bar that is compression-connected to the conductor 5a, 8a is a porcelain tube made of porcelain, 9a is an upper fitting that closes the upper opening of the dredge 8a, 10a is a lower fitting that closes the lower opening, and 11a is integrated with the lower fitting 10a. The cable holding tube 13a is a gel stopper for preventing the gel raw material 12 from flowing out.
Reference numeral 14a denotes an epoxy seat that covers the rubber block 6a, and reference numeral 15a denotes a rubber compression device that presses and holds the rubber block 6a against the cable core by pressing the epoxy seat 14a against the rubber block 6a.

DESCRIPTION OF SYMBOLS 1 Power cable termination | terminus connection part 2 Power cable 3 External semiconductive layer 4 Insulating layer 5 Conductor 6 Rubber block 7 Conductor extraction rod 8 Barrel tube 9 Upper metal fitting 10 Lower metal fitting 11 Cable holding tube 12 Gel raw material 12a Gel-like insulator 13 Gel stopper 21 outer peripheral surface 61 semiconductive rubber part 62 insulating rubber part 81 inner peripheral surface 101 communication port 200 coating device

Claims (6)

In the method of assembling the power cable terminal connecting portion filled with the gel-like insulator in the soot tube into which the end of the power cable is inserted,
A method for assembling a power cable terminal connecting portion, wherein the entire surface of the surface in contact with the gel-like insulator is wetted with a fluid in advance, and then the gel material is injected into the soot tube. The method of assembling a power cable terminal connection part according to claim 1,
A method for assembling a power cable terminal connecting portion, wherein when the fluid is wetted, the fluid is once injected into and discharged from the soot tube. The method of assembling a power cable terminal connection part according to claim 1,
A method for assembling a power cable terminal connecting portion, wherein the fluid is wetted by applying or spraying when the fluid is wetted. The method of assembling a power cable terminal connection part according to claim 1,
The fluid is silicone oil;
The gel-like insulator is a silicone gel,
A method of assembling a power cable terminal connecting portion, wherein the inner peripheral surface of the soot tube is wetted in advance with the silicone oil, and then the raw material of the silicone gel is injected into the soot tube. The method of assembling a power cable terminal connection part according to claim 1,
The fluid is silicone oil;
The gel-like insulator is a silicone gel,
A method of assembling a power cable terminal connecting portion, wherein the power cable is pre-wet with the silicone oil and then the raw material of the silicone gel is injected into the soot tube. The method of assembling a power cable terminal connection part according to claim 1,
The gel-like insulator is a mixture of silicone rubber and silicone oil;
A method for assembling a power cable terminal connecting portion, wherein the fluid is silicone oil.

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