JP6852231B2 - Construction method of the intermediate connection part of the power cable - Google Patents

Description

The present invention relates to a method of constructing an intermediate connection portion of a power cable.

In the intermediate connection part of the conventional power cable connection, the two power cables are stripped off, the exposed conductors are connected to each other by a conductor connecting pipe, the conductor connecting pipe and the conductor are wrapped with a semi-conductive tape, and the conductor is connected. A rubber block insulating cylinder provided with an internal semi-conductive layer was attached to the outside of the portion and the insulating layers on both sides thereof (see, for example, Patent Document 1).
Further, such a rubber block insulating cylinder is inserted into one of the power cables before being connected in advance, and after the conductors are connected to each other, it is slid to a position to cover the conductor connection portion or the like at an appropriate position. (See, for example, Patent Document 2).

Japanese Patent No. 4283778 Japanese Patent No. 4801182

The inner diameter of the rubber block insulating cylinder is set to be smaller than the outer diameter of the insulating layer of the power cable, and when mounted, it self-shrinks and adheres to the insulating layer of the power cable or the tape wound around the conductor connection portion. It has become like.
However, when the rubber block insulating cylinder is slid to the intermediate connection portion of the power cable of Patent Document 1 as in Patent Document 2, the end portion of the semi-conductive tape wound around the outer circumference of the conductor connection portion is rubber. There was a risk that it would be dragged by the block insulation cylinder and unraveled, resulting in a state of being sandwiched between the rubber block insulation cylinder and the insulating layer of the power cable.
In that case, the electrical performance of the intermediate connection portion is deteriorated, and further, electric field concentration is generated at the end portion of the sandwiched semi-conductive tape, which may cause dielectric breakdown.

An object of the present invention is to provide a method for constructing an intermediate connection portion of a power cable with high reliability while suppressing deterioration of electrical performance.

The present invention is a method for constructing an intermediate connection portion of a power cable.
The insertion process of inserting one of the two power cables into the rubber block insulation cylinder,
A connection step of connecting conductors exposed from the insulating layer of the two power cables to form a conductor connection portion, and a connection step.
A step of forming a semi-conductive tape layer in which a semi-conductive tape is wrapped around the outer periphery of the conductor connecting portion, and
A step of forming an outer layer in which a tape having a coefficient of dynamic friction with respect to the rubber block insulating cylinder is wound on the outer periphery of the semi-conductive tape layer is lower than that of the semi-conductive tape.
The rubber block insulating tube, wherein the outer layer is characterized in that it is carried out in order and sliding step sliding in a state to slide the outer layer along the two power cables to a position where the inside.

Further, the present invention is a method for constructing an intermediate connection portion of a power cable.
The insertion process of inserting one of the two power cables into the rubber block insulation cylinder,
A connection step of connecting conductors exposed from the insulating layer of the two power cables to form a conductor connection portion, and a connection step.
A step of forming a semi-conductive tape layer in which a semi-conductive tape is wrapped around the outer periphery of the conductor connecting portion, and
A step of forming an outer layer in which a tape thinner than the semi-conductive tape is wrapped around the outer periphery of the semi-conductive tape layer, and
The rubber block insulating tube, wherein the outer layer is characterized in that it is carried out in order and sliding step sliding in a state to slide the outer layer along the two power cables to a position where the inside.

In the step of forming the semi-conductive tape layer, the semi-conductive tape may be wrapped around the outer periphery of the conductor connecting portion so that the outer diameter is smaller than the outer diameter of the insulating layer of the power cable.

In the step of forming the front Kisotogawa layer, the tape of the outer layer or the semi-conductive tape layer at the end portion of the inserted through the rubber block insulating tube in the insertion step of definitive to the outer layer the power cable side winding You may wind it so that it ends.
The rubber block insulating cylinder may be made of EP rubber.

With the above configuration, the present invention can provide a highly reliable method for forming an intermediate connection portion of a power cable while suppressing a decrease in electrical performance.

It is a front view which cut out a part of the intermediate connection part which connected the power cable. It is an enlarged sectional view around a conductor connection part. It is a front view of the outer layer of the intermediate connection part of a power cable. It is sectional drawing of the outer layer of the intermediate connection part of a power cable. It is explanatory drawing which showed the construction method of the intermediate connection part of a power cable in the order of a process. It is explanatory drawing which showed the construction method of the intermediate connection part of a power cable in the order of a process. It is explanatory drawing which showed the construction method of the intermediate connection part of a power cable in the order of a process. It is explanatory drawing which showed the construction method of the intermediate connection part of the power cable which continued in FIG. 5C in the order of a process. It is explanatory drawing which showed the construction method of the intermediate connection part of a power cable in the order of a process. It is explanatory drawing which showed the construction method of the intermediate connection part of a power cable in the order of a process. It is sectional drawing of another example of the outer layer of the intermediate connection part of a power cable. It is an enlarged sectional view around a conductor connection part in another example of an intermediate connection part. It is an enlarged sectional view around the conductor connection part in the intermediate connection part of the power cable with different outer diameters.

[Outline of Embodiment of the Invention]
Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view in which a part of the intermediate connection portion 100 to which the power cable 10 is connected is cut out, and FIG. 2 is an enlarged cross-sectional view of the periphery of the conductor connection portion 20 described later.
The present embodiment relates to an intermediate connection portion 100 that connects two power cables 10.
The intermediate connecting portion 100 is a semiconducting portion composed of a conductor connecting portion 20 connecting conductors 11 exposed from the insulating layer 12 of the two power cables 10 and a semiconductive tape formed on the outer periphery of the conductor connecting portion 20. The conductive tape layer 30, the outer layer 40 formed on the outside of the semi-conductive tape layer 30, the conductor connecting portion 20, the semi-conductive tape layer 30, and the rubber block insulating cylinder 50 provided on the outside of the outer layer 40. It has.

[Power cable]
The two power cables 10 both have the same configuration, but when they are described separately below, the power cable 10A (the power cable on the left side in FIG. 1) and the power cable 10B (FIG. 1) (Power cable on the right side) is described by another code. Further, for example, when it is not necessary to separately explain the same structure as in the case of explaining the same structure, the power cable 10 is described.

The power cable 10 includes a conductor 11, an insulating layer 12, an external semi-conductive layer 13, and a sheath 14 as a protective layer in this order from the center. The power cable 10 is, for example, a high-voltage power cable having a voltage class of 66 [kV]. The intermediate connection portion 100 can also be applied to a power cable for higher voltage having a voltage class exceeding 66 [kV].

The conductor 11 is made of a good conductor, for example, copper or aluminum.
The insulating layer 12 is formed of a highly insulating resin such as cross-linked polyethylene.
The outer semi-conductive layer 13 is formed of, for example, a semi-conductive rubber obtained by adding carbon to an insulating material such as silicone rubber, ethylene propylene rubber, or chloroprene.
The sheath 14 is made of a material having strength suitable for protecting the inner layer, such as polyethylene.
In addition to these, a configuration having an internal semi-conductive layer, a shielding layer, or the like that a general power cable has may be used.

In the intermediate connection portion 100, the connection end portion of each power cable 10 is step-peeled so that the outer periphery of each of the layers 11, 12, and 13 is exposed. Further, in one power cable 10B, the sheath 14 is excessively removed as compared with the other power cable 10A, and the outer circumference of the outer semi-conductive layer 13 is exposed in a longer range. This is because the rubber block insulating cylinder 50 is temporarily retracted on the exposed external semi-conductive layer 13 of the power cable 10B in the process of constructing the intermediate connection portion 100.

The conductors 11 of the two power cables 10 are individually inserted into both ends of a conductor connecting pipe 21 made of a good conductor in a concentric and facing state, and are electrically connected by brazing, compression, pressure welding, or the like. And this connection structure becomes a conductor connection part 20.
In the conductor connecting portion 20, it is sufficient that the conductors 11 are electrically connected to each other, and the use of the conductor connecting pipe 21 is not essential. For example, the conductors 11 may be directly connected by brazing.

[Semi-conductive tape layer]
Since the outer diameter of each of the conductor 11 and the conductor connecting pipe 21 of each power cable 10 is set to be smaller than that of the insulating layer 12 of the power cable 10, the diameter becomes smaller between the insulating layers 12 of the two power cables 10. A dent occurs.
The semi-conductive tape layer 30 is formed by laminating a number of layers of semi-conductive tape so as to fill the dent. The semi-conductive tape is, for example, a tape in which a semi-conductive adhesive material is applied to the back surface of a conductive vulcanized rubber sheet. The semi-conductive tape layer 30 is formed by winding the semi-conductive tape in multiple layers with the back surface facing inward (for example, 1/2 wrap winding). The wrap winding means winding the tape so as to overlap a part of the tape in the width direction, and has a cross section as shown in FIGS. 4 and 7. The 1/2 wrap winding is a winding method in which 1/2 of the tape in the width direction is overlapped.
The semi-conductive tape may be a tape made of another material having semi-conductivity, and an adhesive material is not essential, and a self-bonding tape or the like may be used.

[Outer layer]
The outer diameter of the semi-conductive tape layer 30 is set smaller than the outer diameter of the insulating layer 12 of the power cable 10.
An outer layer 40 made of the semi-conductive cross-linked polyethylene tape 41 is formed on the outer periphery of the semi-conductive tape layer 30. FIG. 3 is a front view of the outer layer 40.
The semi-conductive cross-linked polyethylene tape 41 may have a smaller number of layers than the semi-conductive tape layer 30, and may be, for example, one layer.
The semi-conductive cross-linked polyethylene tape 41 is a tape made of semi-conductive cross-linked polyethylene and coated with a semi-conductive adhesive material on the back surface. The back surface of the semi-conductive cross-linked polyethylene tape 41 is wound inward by wrapping (for example, 1/2 wrap) to form the outer layer 40.
Further, the surface of the semi-conductive cross-linked polyethylene tape 41 has a main insulating portion 51 and an internal semi-conductive portion 52 of the rubber block insulating cylinder 50, which will be described later, as compared with the surface of the semi-conductive tape constituting the semi-conductive tape layer 30. The dynamic friction coefficient is small for both the stress cones 53 and 54. When the rubber block insulating cylinder 50 is attached, the rubber block insulating cylinder 50 slides on the surface of the semi-conductive cross-linked polyethylene tape 41, so that it is preferable that the dynamic friction coefficient is small in this way. Further, when the rubber block insulating cylinder 50 is attached, the semi-conductive cross-linked polyethylene tape 41 may have a semi-conductive tape layer 30 because the slide may be restarted by stopping in the middle for checking the dimensions and the like. It is more preferable that the coefficient of static friction is smaller than that of the surface of the constituent semi-conductive tape.

The outer diameter of the outer layer 40 is slightly smaller than that of the insulating layer 12 of the power cable 10 over the entire length in the central axial direction (hereinafter referred to as the axial direction) of the power cable 10, and the difference in outer diameter with respect to the insulating layer 12 is large. , Greater than 0 and less than 5 [mm]. A rubber block insulating cylinder 50 is arranged further outside the outer layer 40. Since the rubber block insulating cylinder 50 has elasticity and contractility, the outer layer has an outer diameter difference of 5 [mm] or less. The outer circumference of the 40 and the inner circumference of the rubber block insulating cylinder 50 have a portion in close contact with each other, and conductivity is ensured between the outer circumference of the outer layer 40 and the inner semi-conductive portion 52 of the rubber block insulating cylinder 50. Further, even if a gap is generated due to a step between the outer layer 40 and the insulating layer 12 of the power cable 10, the insulating layer 12 includes the rubber block insulating cylinder 50, the internal semiconductive portion 52, and the stress cone 53. Since there is no gap that is surely adhered to any of the 54 and is accompanied by dielectric breakdown, and the outer layer 40 can secure the conductivity with the inner semi-conductive portion 52, the electrical characteristics are excellent. Does not cause a drop.
The difference in the outer diameter of the outer layer 40 with respect to the outer diameter of the insulating layer 12 is more preferably 0.4 [mm] or more and 1 [mm] or less.
The difference in outer diameter between the outer layer 40 and the insulating layer 12 of the power cable 10 may be 0.

Further, as shown in FIG. 3, the end portion 411 of the winding end of the semi-conductive cross-linked polyethylene tape 41 of the outer layer 40 is located on the power cable 10B side of the outer layer 40, more preferably at the end portion thereof.
As described above, the exposed length of the external semi-conductive layer 13 of the power cable 10B (the removal length of the sheath 14) is longer than that of the power cable 10A, and the rubber block insulating cylinder 50 is temporarily used in the construction process of the intermediate connection portion 100. It becomes a typical evacuation area (see FIGS. 5C to 6B).
Then, the temporarily retracted rubber block insulating cylinder 50 slides to the power cable 10A side and is arranged at a regular position where the periphery of the conductor connecting portion 20 is stored inside.
At this time, the end portion 411 at the end of winding of the semi-conductive cross-linked polyethylene tape 41 may be slidably contacted with the inner circumference of the rubber block insulating cylinder 50 and peeled off, and may move in the same direction as the rubber block insulating cylinder 50. As a result, if the end portion 411 at the end of winding of the semi-conductive cross-linked polyethylene tape 41 moves to the power cable 10A side of the internal semi-conductive portion 52 of the rubber block insulating cylinder 50 described later, the electrical characteristics deteriorate. It may cause dielectric breakdown in the rubber block insulating cylinder 50.
However, since the end portion 411 at the end of winding of the semi-conductive cross-linked polyethylene tape 41 is located on the outermost layer 40 on the power cable 10B side and farthest from the power cable 10A, the power is higher than that of the internal semi-conductive portion 52. The possibility of moving to the cable 10A side can be sufficiently reduced.

[Rubber block insulation cylinder]
As shown in FIG. 1, the rubber block insulating cylinder 50 has a cylindrical shape along the axial direction, and both ends thereof have a shape in which the diameter is gradually reduced. Further, a central hole 56 through which the conductor connecting portion 20 of the power cable 10 is inserted is formed through the center of the rubber block insulating cylinder 50.

The rubber block insulating cylinder 50 includes a main insulating portion 51 made of EP rubber (ethylene propylene rubber) which is an insulator, and an internal semi-conductive portion 52 provided in the central portion in the axial direction inside the main insulating portion 51. The main insulating portion 51 has stress cones 53 and 54 formed at one end and the other end in the axial direction. Further, an external semi-conductive portion 55 is formed on the outer periphery of the main insulating portion 51 except for a part that becomes an end portion on the power cable 10B side.
The inner semi-conductive portion 52, the stress cones 53 and 54, and the outer semi-conductive portion 55 are formed of semi-conductive rubber obtained by adding carbon to an insulating material such as silicone rubber, ethylene propylene rubber, or chloroprene.

The central hole 56 has a uniform inner diameter over the entire length, and penetrates the central hole 56 so that the entire rubber block insulating cylinder 50 is axisymmetric. That is, the central hole 56 is stressed from one end side (power cable 10A side) of the rubber block insulating cylinder 50 to the stress cone 53, the internal semiconductive portion 52, and the other end side (power cable 10B side) of the rubber block insulating cylinder 50. It penetrates the cone 54 in order.
The inner diameter of the central hole 56 is set to be smaller than the outer diameter of the outer semi-conductive layer 13 and the insulating layer 12 of the power cable 10, and further is set to be smaller than the outer diameter of the outer layer 40. Therefore, it self-shrinks when attached and comes into close contact with the power cable 10. Specifically, the outer diameter of the insulating layer 12 of the power cable 10 is 1.1 times or more and 1.5 times or less with respect to the inner diameter of the central hole 56 of the rubber block insulating cylinder 50.

The internal semi-conductive portion 52 is longer than the outer layer 40 described above in the axial direction. Further, the inner circumference of the inner semi-conductive portion 52 is in close contact with the outer circumference of the outer layer 40 and is in a state of being electrically connected. When the power cable 10 is energized, the inner semi-conductive portion 52 is connected to the conductor connecting portion 20. It becomes the same potential as.

Further, the stress cones 53 and 54 are in close contact with the end of the outer semi-conductive layer 13 of the power cable 10A and the end of the outer semi-conductive layer 13 of the power cable 10B, respectively, and are electrically connected to each other. ing. When the power cable 10 is energized, the stress cones 53 and 54 have the same potential as the external semiconductive layer 13 of the power cable 10A and the external semiconductive layer 13 of the power cable 10B.

[How to install the intermediate connection of the power cable]
The construction method of the intermediate connection portion 100 of the power cable having the above configuration will be described with reference to FIGS. 5A to 6C.
First, as shown in FIG. 5A, the insulating layer 12, the outer semi-conductive layer 13, and the sheath 14 of the two power cables 10A and 10B to be connected are stripped off, and the conductor 11, the insulating layer 12, and the outer semi-conductive layer 13 are stripped. The outer circumference of the power cable is exposed (power cable processing process).
At this time, as shown in the drawing, the sheath 14 of the outer semi-conductive layer 13 of the power cable 10B is removed so that the exposed length thereof is at least longer than the total length of the rubber block insulating cylinder 50.

Next, as shown in FIG. 5B, a jig 101 for inserting into the center hole 56 of the rubber block insulating cylinder 50 is attached to the tip of the power cable 10B.
Then, as shown in FIG. 5C, the power cable 10B and the rubber block insulating cylinder 50 are held concentrically, and the power cable 10B is inserted into the center hole 56 of the rubber block insulating cylinder 50 by using a press-fitting device (not shown). (Insert process).
At this time, it is preferable to apply a lubricant such as silicone in advance to the outer circumferences of the insulating layer 12 and the external semi-conductive layer 13 of the jig 101 and the power cable 10B.
The rubber block insulating cylinder 50 is temporarily arranged on the outer periphery of the outer semi-conductive layer 13 of the power cable 10B.

Next, as shown in FIG. 6A, the jig 101 of the power cable 10B is removed, and the conductors 11 of the power cables 10A and 10B are connected to each other by the conductor connecting pipe 21 to form the conductor connecting portion 20 (connection step). ).
Further, as shown in FIG. 6B, the semi-conductive tape is wound around the exposed conductor 11 and the outer periphery of the conductor connecting tube 21 by wrapping to form the semi-conductive tape layer 30 (formation of the semi-conductive tape layer). Process).

Then, the semi-conductive cross-linked polyethylene tape 41 is wrapped around the outer circumference of the semi-conductive tape layer 30 by wrapping to form the outer layer 40 (the step of forming the outer layer).
The semi-conductive cross-linked polyethylene tape 41 is wound so that the end end is wound at the end of the outer layer 40 on the power cable 10B side, and the outer diameter of the outer layer 40 at the end of winding is the insulating layer 12 of the power cable 10. Make it slightly smaller than the outer diameter.

Next, as shown in FIG. 6C, the rubber block insulating cylinder 50 is slid toward the power cable 10A side so as to be properly arranged (sliding step).
Also in this case, it is preferable to apply a lubricant such as silicone in advance to the outer circumference of the outer layer 40, the insulating layer 12 of the power cable 10A, and the outer circumference of the outer semi-conductive layer 13.

In the proper arrangement of the rubber block insulating cylinder 50, the internal semi-conductive portion 52 is connected to the outer periphery of the conductor connecting portion 20, and the stress cones 53 and 54 are connected to the outer semi-conductive layer 13 of the power cable 10A, respectively. It is in a state of being connected to the external semi-conductive layer 13 of the power cable 10B.
As a result, the construction of the intermediate connection portion 100 of the power cable is completed.

[Technical Effects of Embodiments of the Invention]
The intermediate connection portion 100 of the power cable has an outer layer 40 made of a semi-conductive cross-linked polyethylene tape 41 having a lower dynamic friction coefficient with respect to the rubber block insulating cylinder 50 than the semi-conductive tape on the outer periphery of the semi-conductive tape layer 30. I have.
Therefore, during the construction of the intermediate connection portion 100, the rubber block insulating cylinder 50 smoothly slides and passes through the outer periphery of the outer layer 40, so that the semi-conductive tape and the semi-conductive cross-linked polyethylene tape 41 are damaged by sliding. It is possible to prevent the end portion from being dragged and being caught in the gap between the rubber block insulating cylinder 50 and the insulating layer 12. As a result, it is possible to suppress deterioration of electrical performance such as electric field irregularity due to pinching of foreign matter and occurrence of dielectric breakdown due to electric field concentration, and to provide a highly reliable intermediate connection portion.
Further, when the semi-conductive cross-linked polyethylene tape 41 has a lower static friction coefficient with respect to the rubber block insulating cylinder 50 than the semi-conductive tape, the movement of the semi-conductive cross-linked polyethylene tape 41 is stopped halfway and moved again when the rubber block insulating cylinder 50 is attached. Even in such a case, it is possible to suppress deterioration of electrical performance and occurrence of dielectric breakdown due to electric field concentration, and it is possible to provide an intermediate connection portion with higher reliability.
In particular, since the outer layer 40 is made of a semi-conductive cross-linked polyethylene tape 41 having adhesiveness on one side, the dynamic friction coefficient is reduced and good electrical connection with the conductor connecting portion 20 is realized, and the conductor. The same potential can be obtained from the connecting portion 20 to the internal semi-conductive portion 52 of the rubber block insulating cylinder 50.

Further, since the outer diameter of the insulating layer 12 of the power cable 10 is 1.1 times or more and 1.5 times or less the inner diameter of the central hole 56 of the rubber block insulating cylinder 50, the inner wall of the central hole 56 of the rubber block insulating cylinder 50 is formed. It is in close contact with the insulating layer 12, the external semi-conductive layer 13, and the outer layer 40 of the power cable 10, and good insulation performance and electrical connection can be obtained.
Further, since the outer diameter of the outer layer 40 is smaller than the outer diameter of the insulating layer 12 of the power cable 10, the semi-conductive tape or the semi-conductive cross-linked polyethylene tape 41 is damaged when the rubber block insulating cylinder 50 is slid. , Entrainment in the gap can be effectively suppressed, and it becomes possible to provide an intermediate connection portion having better electrical characteristics.
Further, since the outer diameter of the outer layer 40 is set smaller than the outer diameter of the insulating layer 12 of the power cable 10 within a range of 5 [mm] or less, it self-shrinks when the rubber block insulating cylinder 50 is attached. As a result, the outer layer 40 and the inner semi-conductive portion 52 can be brought into close contact with each other, and the conductor connecting portion 20 to the inner semi-conductive portion 52 can be stably at the same potential.
Further, when the outer diameter of the outer layer 40 is set smaller than the outer diameter of the insulating layer 12 of the power cable 10 in the range of 0.4 [mm] or more and 1 [mm] or less, the rubber block insulating cylinder 50 self-shrinks. While ensuring contact with the outer layer 40 by the force, it is possible to suppress the frictional force at the time of sliding and effectively prevent the tape from being caught.
Further, since the semi-conductive cross-linked polyethylene tape 41 of the outer layer 40 is wrapped around, it is possible to effectively reduce the occurrence of gaps between the tapes.

Further, the exposed length of the outer semi-conductive layer 13 on the lower side of the sheath 14 on the power cable 10B side is longer than that on the power cable 10A side, and the end portion 411 of the winding end of the semi-conductive cross-linked polyethylene tape 41 is the outer layer. It is located on the power cable 10B side, more preferably on the end side, than the axial intermediate position in 40. Therefore, when the rubber block insulating cylinder 50 slides from the outer semi-conductive layer 13 of the power cable 10B to the power cable 10A side during construction, the end portion 411 of the winding end of the semi-conductive crosslinked polyethylene tape 41 Is located far from the power cable 10A, and even if peeling occurs, it effectively suppresses the internal semi-conductive portion 52 from being dragged to the power cable 10A side and being sandwiched between the insulator 12 and the power cable 10. It is possible to provide an intermediate connection portion having better electrical characteristics.

Further, the two power cables 10A and 10B exemplify the case where the voltage class is 66 [kV] or more, but even such a high voltage cable has good electrical characteristics. It is possible to provide an intermediate connection.

Further, the intermediate connection portion 100 of the power cable forms the conductor connection portion 20 by connecting the conductors 11 of the two power cables 10A and 10B to each other in the insertion step of inserting the power cable 10B into the rubber block insulating cylinder 50. A connection step, a step of forming a semi-conductive tape layer 30 in which a semi-conductive tape is wound around the outer periphery of the conductor connecting portion 20, and an outer layer 40 in which a semi-conductive crosslinked polyethylene tape 41 is wound around the outer periphery of the semi-conductive tape layer 30. A plurality of steps including a forming step and a sliding step of sliding the rubber block insulating cylinder 50 along the two power cables 10A and 10B to a position where the internal semi-conductive portion 52 covers the outer layer 40 are in the order described above. Construction will be done at.
Therefore, in the sliding process, the rubber block insulating cylinder 50 smoothly slides and passes through the outer periphery of the outer layer 40, so that the semi-conductive tape or the semi-conductive cross-linked polyethylene tape 41 is damaged or the end of the tape winding end. Entrainment of 411 is reduced, deterioration of electrical performance and occurrence of dielectric breakdown are suppressed, and highly reliable construction can be performed.

[Other]
The embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and the details shown in the embodiment can be appropriately changed without departing from the spirit of the invention.
For example, the material of each configuration constituting the intermediate connection portion 100 of the power cable is only an example, and can be changed as appropriate.
Specifically, the main insulating portion 51 of the rubber block insulating cylinder 50 may be any insulating material, and may be silicone rubber or chloroprene, which is an insulating material other than ethylene propylene rubber.

Further, as in the outer layer 40C shown in FIG. 7, the outer layer 40C may be formed by a tape 41C thinner than the semiconductive tape of the semiconductive tape layer 30. For example, when the semi-conductive tape of the semi-conductive tape layer 30 is 0.7 [mm], the thickness of the tape 41C is 0.1 to 0.5 [mm]. These numerical values are examples.
In this case, as is clear from the comparison with FIG. 4, the unevenness generated on the surface of the outer layer 40C can be made smaller than the unevenness of the outer layer 40, and the entrainment of the outer layer 40C by the rubber block insulating cylinder 50 can be reduced. Is possible.

In this way, even when the outer layer 40C is formed from the tape 41C thinner than the semi-conductive tape of the semi-conductive tape layer 30, the power cable can be formed in the same steps as those shown in FIGS. 5A to 6C. It is possible to construct an intermediate connection part.

Since the outer layer 40C can reduce the coefficient of dynamic friction with respect to the rubber block insulating cylinder 50 due to its structure, the material is semi-conductive cross-linked polyethylene having a smaller coefficient of dynamic friction than the semi-conductive tape of the semi-conductive tape layer 30. Instead of using the tape, it may be made of a semi-conductive tape made of the same material as the semi-conductive tape layer 30.
Further, regardless of whether the outer layer 40C is a semi-conductive cross-linked polyethylene tape having a small dynamic friction coefficient or a semi-conductive tape made of the same material as the semi-conductive tape layer 30, the outer layer 40C is also the insulating layer 12 of the power cable 10. It is preferably smaller in the range of 5 [mm] or less than the outer diameter, and more preferably smaller in the range of 0.4 [mm] or more and 1 [mm] or less.

Further, as shown in FIG. 8, the semi-conductive tape layer 30 may be formed with a diameter smaller than that of the insulating layer 12 of the power cable 10 without forming the outer layer 40. In this case, the outer diameter of the semi-conductive tape layer 30 is smaller than that of the insulating layer 12 of the power cable 10 in the range of 5 [mm] or less, and further, in the range of 0.4 [mm] or more and 1 [mm] or less. It is preferable to have a small diameter. Further, in this case as well, it is preferable that the semi-conductive tape layer 30 is wrapped.
In the above case, the rubber block insulating cylinder 50 and the semi-conductive tape layer 30 come into contact with each other due to the self-shrinking force of the rubber block insulating cylinder 50, but the semi-conductive tape layer 30 has a smaller diameter, so that the rubber block insulating cylinder 50 has a smaller diameter. The dynamic friction force and the static friction force are reduced, the entrainment of the semi-conductive tape can be reduced, and the deterioration of the electrical performance and the occurrence of dielectric breakdown due to the concentration of the electric field can be suppressed.

As described above, even when the semi-conductive tape layer 30 is formed having a diameter smaller than that of the insulating layer 12 of the power cable 10, in the steps shown in FIGS. 5A to 6C, in the step of FIG. 6B. It is possible to construct the intermediate connection portion of the power cable by forming the outer diameter of the semi-conductive tape layer 30 with the above-mentioned target outer diameter by wrapping and changing the outer diameter so as not to form the outer layer 40. ..
At this time, the semi-conductive tape is wound so that the end portion of the semi-conductive tape layer 30 ends at the end of the semi-conductive tape layer 30 on the power cable 10B side.

Further, as shown in FIG. 9, when the outer diameters of the insulating layer 12 of the power cable 10A and the power cable 10B do not match (an example where the power cable 10B is larger), the insulating layer 12 of the power cable 10A is illustrated. The semi-conductive tape layer 30 and the outer layer 40 are wrapped with tape so that a conical surface parallel to the conical surface Q connecting the tip of the power cable 10B and the tip of the insulating layer 12 of the power cable 10B is formed. It is preferable to form.
In this case, the outer diameter R1 of the conical surface of the outer layer 40 is a cone that connects the tip of the insulating layer 12 of the power cable 10A and the tip of the insulating layer 12 of the power cable 10B at any position in the axial direction. It is smaller than the outer diameter R2 of the surface Q.
When the outer layer 40 is not formed as shown in FIG. 8, the semi-conductive tape layer 30 is connected to the tip of the insulating layer 12 of the power cable 10A and the tip of the insulating layer 12 of the power cable 10B. It is preferable to wrap the tape so that a conical surface parallel to the conical surface is formed. In this case as well, the outer diameter of the conical surface of the semi-conductive tape layer 30 determines the tip of the insulating layer 12 of the power cable 10A and the tip of the insulating layer 12 of the power cable 10B at any position in the axial direction. It is smaller than the outer diameter of the connecting conical surfaces.
In the case of FIG. 9 (including the case where the example of FIG. 8 is applied to FIG. 9), the outer diameter of the conical surface of the outer layer 40 (semi-conductive tape layer 30) can be set at any position in the axial direction. It is smaller than the outer diameter of the conical surface Q connecting the tip of the insulating layer 12 of the power cable 10A and the tip of the insulating layer 12 of the power cable 10B. Further, at any position in the axial direction, the outer diameter of the conical surface of the outer layer 40 (semi-conductive tape layer 30) is made smaller than the outer diameter of the conical surface Q within a range of 5 [mm] or less, and further. , It is preferable that the diameter is small in the range of 0.4 [mm] or more and 1 [mm] or less.

The present invention can be used for power cables.

10, 10A, 10B Power cable 11 Conductor 12 Insulation layer 13 External semi-conductive layer 14 Sheath 20 Conductor connection 21 Conductor connection tube 30 Semi-conductive tape layer 40, 40C Outer layer 41 Semi-conductive crosslinked polyethylene tape 41C Tape 411 End of winding End 50 Rubber block Insulation cylinder 51 Main insulation 52 Internal semi-conductive part 53, 54 Stress cone 55 External semi-conductive part 56 Center hole 100 Intermediate connection part

Claims (5)

The insertion process of inserting one of the two power cables into the rubber block insulation cylinder,
A connection step of connecting conductors exposed from the insulating layer of the two power cables to form a conductor connection portion, and a connection step.
A step of forming a semi-conductive tape layer in which a semi-conductive tape is wrapped around the outer periphery of the conductor connecting portion, and
A step of forming an outer layer in which a tape having a coefficient of dynamic friction with respect to the rubber block insulating cylinder is wound on the outer periphery of the semi-conductive tape layer is lower than that of the semi-conductive tape.
Power cable and performs the rubber block insulating tube, and a sliding step for sliding in a state in which the outer layer slides on the outer layer along the two power cables to a position where the inner sequentially Construction method of the intermediate connection part of. The insertion process of inserting one of the two power cables into the rubber block insulation cylinder,
A connection step of connecting conductors exposed from the insulating layer of the two power cables to form a conductor connection portion, and a connection step.
A step of forming a semi-conductive tape layer in which a semi-conductive tape is wrapped around the outer periphery of the conductor connecting portion, and
A step of forming an outer layer in which a tape thinner than the semi-conductive tape is wrapped around the outer periphery of the semi-conductive tape layer, and
Power cable and performs the rubber block insulating tube, and a sliding step for sliding in a state in which the outer layer slides on the outer layer along the two power cables to a position where the inner sequentially Construction method of the intermediate connection part of. The step of forming the semi-conductive tape layer is characterized in that a semi-conductive tape is wound around the outer periphery of the conductor connecting portion so that the outer diameter is smaller than the outer diameter of the insulating layer of the power cable. Alternatively, the method for constructing the intermediate connection portion of the power cable according to 2. In the step of forming the outer layer, according to claim 1, characterized in that winding the like the tape of said outer layer in said insertion step by the rubber blocks inserted through said power cable side insulation tube in the outer layer finishes winding A method for constructing an intermediate connection portion of a power cable according to any one of 3 to 3. The method for constructing an intermediate connection portion of a power cable according to any one of claims 1 to 4, wherein the rubber block insulating cylinder is made of EP rubber.

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