JP2019213331A - Terminal connection part - Google Patents

Abstract

To provide a terminal connection part which can reconcile mechanical strength and improvement of workability at the terminal connection part using a polymer porcelain tube.SOLUTION: A terminal connection part 1a is provided with a polymer porcelain tube 2 having cylindrically formed body parts 20a, 21a, and shade parts 20b, 21b provided in the surroundings of the body parts 20a, 21a. The polymer porcelain tube 2 is constituted of insulator parts 20, 21, and a diameter variance engagement part 21c into which an end of a power cable 100 is inserted is formed in the insulator part 21. The insulator part 21 consists of a polymeric material having an elastic modulus of 2 MPa or less, and the insulator part 20 consists of a polymeric material having an elastic modulus higher than that of a material constituting the insulator part 21. A characteristic frequency of the shade part 20b is 200 Hz or more. An interface between the insulator part 20 and the insulator part 21 is formed in an area where electric field intensity becomes 5 kV/mm or less when high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power cable termination connection.

  Conventionally, at the end of a high-voltage power cable, a terminal connection portion is used to connect the power cable to a bare wire or an insulated wire. The terminal connection portion includes a cylindrical soot that can be inserted with a power cable. Many soot tubes are made of porcelain, but there is a problem that their weight is heavy and difficult to handle.

  Therefore, in recent years, polymer soot tubes made of a polymer material such as silicone rubber have been developed. Such polymer pipes are advantageous in that they are lighter and easier to handle than porcelain pipes.

  Patent Document 1 discloses that a terminal connection using a polymer pipe having a pipe embedded in a cable insertion hole is provided for the purpose of providing a terminal connection portion that can maintain the position even when used in a horizontal position. Part (polymer connection part) is described.

Japanese Patent Laid-Open No. 2006-116281

  However, according to the study of the present inventor, it has been found that it is difficult to achieve both improvement in mechanical strength and workability in the terminal connection portion using the polymer pipe. Specifically, when the elastic modulus (or hardness) of the polymer material constituting the polymer rod is increased in order to make the polymer rod have sufficient mechanical strength, it becomes difficult to insert the power cable into the polymer rod. Thereby, the problem that workability | operativity falls arises.

  On the other hand, when the elastic modulus (or hardness) of the polymer material constituting the polymer soot tube is lowered in order to improve workability, the polymer soot tube is easily deformed. As a result, the service life of the terminal connection portion is shortened, and the electrical performance may be deteriorated.

  The present invention has been made in view of the problems as described above, and provides a terminal connection part that can achieve both improvement in mechanical strength and workability in the terminal connection part using a polymer pipe. Objective.

  Of the inventions disclosed in the present application, the outline of typical ones will be briefly described as follows.

  [1] The terminal connection portion includes a polymer soot tube having a cylindrical main body portion through which a power cable can be inserted and a shade portion provided around the main body portion. The said polymer soot pipe is comprised by the 1st insulator part and the 2nd insulator part which are arrange | positioned along the insertion direction of the said power cable. A diameter difference fitting portion into which an end portion of the power cable is inserted is formed in the second insulator portion, and the diameter difference fitting portion is formed before the end portion of the power cable is inserted. The inner diameter is the same as or smaller than the outer diameter of the end portion. The second insulator part is made of a polymer material having an elastic modulus of 2 MPa or less, and the first insulator part is made of a polymer material having an elastic modulus higher than that of the material constituting the second insulator part. Become. The natural frequency of the cap portion formed in the first insulator portion is 200 Hz or more, and an interface between the first insulator portion and the second insulator portion is 6.6 kV by the power cable. When transmitting a high voltage of ˜500 kV, it is formed in a region where the electric field strength is 5 kV / mm or less.

  [2] In the terminal connection portion according to [1], the interface includes a surface along an equipotential surface.

  [3] In the terminal connection portion according to [1], the interface includes a surface perpendicular to the axial direction of the polymer soot tube.

  ADVANTAGE OF THE INVENTION According to this invention, the termination | terminus connection part which can make mechanical strength and workability improvement compatible can be provided in the termination | terminus connection part using a polymer soot pipe.

It is a longitudinal cross-sectional view of the termination | terminus connection part which concerns on one embodiment of this invention. It is a cross-sectional view of the power cable connected to the termination | terminus connection part shown in FIG. FIG. 2 is a schematic diagram showing the result of analyzing the equipotential surface of the generated electric field in the enlarged vertical sectional view of the main part of the terminal connection portion shown in FIG. 1. FIG. 3 is a schematic diagram showing a result of analyzing an elastic strain distribution generated by an external force in the main part enlarged longitudinal sectional view of the terminal connection part shown in FIG. 1. It is a longitudinal cross-sectional view of the termination | terminus connection part of the 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the termination | terminus connection part of the 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the termination | terminus connection part of a prior art example.

(Embodiment 1)
Hereinafter, a first embodiment of the present invention (hereinafter referred to as a first embodiment) will be described with reference to the drawings. In the drawings showing the embodiments, the same or similar parts are denoted by the same or similar symbols or reference numerals, and description thereof will not be repeated in principle.

<Terminal connection configuration>
FIG. 1 is a longitudinal sectional view showing a configuration example of a termination connection unit according to the first embodiment. As shown in FIG. 1, the terminal connection portion 1 a according to Embodiment 1 includes a polymer soot tube 2. Moreover, the termination | terminus connection part 1a is the protective metal fitting 3 which protects the rear end side (the side where the power cable 100 is inserted) of the polymer rod 2, the conductor connection rod 4 connected to the conductor 120 of the power cable 100, and conductor connection A fixed terminal 5 to which the rod 4 is attached, a high-voltage shield 6 connected to the conductor connecting rod 4 via the fixed terminal 5, and a waterproof processing unit 7 that seals between the protective metal fitting 3 and the power cable 100 are further provided. ing.

<Configuration of polymer pipe>
As shown in FIG. 1, the polymer rod 2 according to the first embodiment includes a main body 20a, 21a formed in a cylindrical shape through which the power cable 100 can be inserted, and a cap provided around the main body 20a, 21a. Part 20b, 21b.

  The polymer soot tube 2 is composed of two insulator parts arranged along the insertion direction of the power cable 100, that is, a first insulator part 20 and a second insulator part 21. The second insulator portion 21 is made of a polymer material having an elastic modulus of 2 MPa or less, and the first insulator portion 20 is made of a polymer material having an elastic modulus higher than the material constituting the second insulator portion 21. Become.

  As will be described later, in order to facilitate the insertion of the end 101 of the power cable 100 into the diameter difference fitting part 21c, the second insulator part 21 constituting the diameter difference fitting part 21c has an elastic modulus of 2 MPa or less. It is preferable to consist of the material which has. Moreover, in order to make it easy to insert the end portion 101 of the power cable 100 into the diameter difference fitting portion 21c, the second insulator portion 21 is preferably made of a polymer material having a hardness of about Shore A40.

  As will be described later, in order to set the natural frequency of the cap portion 20b to 200 Hz or more, the first insulator portion 20 is preferably made of a polymer material having a hardness of about Shore A70.

  Further, the polymer material constituting the first insulator portion 20 and the second insulator portion 21 has good water repellency, dielectric strength (dielectric breakdown field strength, insulation strength) of 5 kV / mm or more, and stress relaxation. A small material is preferred. Further, it is preferable that the polymer material constituting the first insulator part 20 and the polymer material constituting the second insulator part 21 have good adhesion to each other. Examples of the polymer material constituting the first insulator portion 20 and the second insulator portion 21 include silicone rubber, ethylene propylene rubber (EPM), and ethylene propylene diene rubber (EPDM). As the polymer material constituting the second insulator portion 21, silicone rubber having an elastic modulus of 1.5 MPa is more preferable.

  The first insulator portion 20 is located on the front end side of the polymer soot tube 2 (the side opposite to the side into which the power cable 100 is inserted), and the second insulator portion 21 is on the rear end side of the polymer soot tube 2 (the power cable 100 is It is located on the same side as the side to be inserted. Although details will be described later, the interfaces (bonding surfaces) between the first insulator portion 20 and the second insulator portion 21 are the interfaces 25a and 25b. That is, with respect to the interfaces 25a and 25b, the leading end side of the polymer soot tube 2 is constituted by the first insulator portion 20, and the rear end side of the polymer soot tube is constituted by the second insulator portion 21. Further, the interfaces 25a and 25b between the first insulator part 20 and the second insulator part 21 have an electric field strength of 5 kV / mm or less when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100. It is formed in the area.

  Although details will be described later, the interface 25a between the first insulator portion 20 and the second insulator portion 21 of the first embodiment is along an equipotential surface (equipotential line). Specifically, the interface 25a has a shape that gradually decreases in diameter from the front end side to the rear end side of the polymer rod 2. Further, the interface 25 b between the first insulator portion 20 and the second insulator portion 21 is perpendicular to the axial direction of the polymer soot tube 2. For the following description, FIG. 1 also shows an interface 25c (examination example 2) and an interface 25d (examination example 1), which are different interfaces from the interfaces 25a and 25b.

  The 1st insulator part 20 has the main-body part 20a and the some cap part 20b provided in the circumference | surroundings of the main-body part 20a. The second insulator portion 21 includes a main body portion 21a, a plurality of shade portions 21b provided around the main body portion 21a, and a diameter difference fitting portion 21c into which the end portion 101 of the power cable 100 is inserted. Yes. The diameter difference fitting portion 21c has an inner diameter smaller than or equal to the outer diameter D1 of the end portion 101 of the power cable 100, that is, the insulating layer 140 of the power cable 100, before the end portion 101 of the power cable 100 is inserted. Have.

  Further, the natural frequency of the cap portion 20b formed in the first insulator portion 20 of the first embodiment is 200 Hz or more. Therefore, as described above, the polymer material constituting the first insulator portion 20 is selected so that the natural frequency of the cap portion 20b is 200 Hz or more, and the shape such as the height and width of the cap portion 20b is selected. It is preferable to design. In addition, when the height of the cap portions 20b and 21b is lowered (the depth of the grooves of the cap portions 20b and 21b is decreased), the rigidity is increased and the natural frequency is increased, but the height of the cap portions 20b and 21b is increased. If it is too low (the depth of the grooves of the cap portions 20b and 21b is too small), the surface leakage distance becomes short and the risk of creeping discharge increases. Therefore, it is preferable that the height of the cap portions 20b and 21b is not too low (the depth of the grooves of the cap portions 20b and 21b is too small). As shown in FIG. 1, in the first embodiment, most of the shade portions 20b and 21b existing in the polymer rod 2 are occupied by the shade portion 20b.

  In addition to the first insulator portion 20 and the second insulator portion 21, the polymer soot tube 2 includes an embedded flange 22 embedded on the outer peripheral surface side of the second insulator portion 21, and the first insulator portion 20. And an embedded pipe 23 embedded on the inner peripheral surface side of the second insulator portion 21 so as to face the insulating layer 140 of the end portion 101 of the power cable 100. The embedded flange 22 and the embedded pipe 23 act as a reinforcing member or a core material for the polymer rod 2.

  The polymer rod 2 includes a semiconductive portion (first semiconductive portion) 24a for relaxing the electric field at the end 101 of the power cable 100 and a semiconductive portion (second semiconductive portion) for relaxing the electric field at the embedded flange 22. ) 24b and a semiconductive portion (third semiconductive portion) 24c for relaxing the electric field in the embedded pipe 23.

  The embedded flange 22 includes a cylindrical portion 22a formed in a cylindrical shape and a flange portion 22b provided over the entire outer peripheral surface of the cylindrical portion 22a. Further, the embedded flange 22 is provided on the outer peripheral surface side of the second insulator portion 21 so that the mounting surface 22c attached to another member such as the casing 201 to be connected is exposed from the second insulator portion 21. Buried. An internal thread 22d is formed on the attachment surface 22c, and the embedded flange 22 can be attached to the housing 201 or the like by, for example, a bolt 30. The embedded flange 22 is made of a metal such as brass or an aluminum alloy, for example. The embedded flange 22 is connected to the ground potential when in use.

  The embedded pipe 23 is made of a metal material such as brass or an aluminum alloy, for example. Moreover, the embedded pipe 23 has an outer diameter of 30 to 50 mm and a thickness of 2 to 5 mm, for example. In the first embodiment, since the metal embedded pipe 23 is embedded in the inner peripheral surface of the first insulator portion 20, the horizontal posture is maintained even when the terminal connection portion 1a is used in a horizontal posture. be able to. The embedded pipe 23 is formed with a cable insertion hole (second cable insertion hole) 2b having an inner diameter D2 larger than the outer diameter of the insulating layer 140. As a result, the power cable 100 can be easily inserted into the embedded pipe 23.

  The semiconductive portions 24a, 24b, and 24c are formed by, for example, extruding a conductive powder such as carbon dispersed in silicone rubber, ethylene propylene rubber (EPM), ethylene propylene diene rubber (EPDM), or the like to provide conductivity. It is formed by doing.

  A cable insertion hole (first cable insertion hole) 2a is formed on the rear end side of the polymer rod 2 in the semiconductive portion 24a. The semiconductive portion 24a has the same inner diameter as the inner diameter of the diameter difference fitting portion 21c. Therefore, when the end portion 101 of the power cable 100 is inserted into the semiconductive portion 24a and the diameter difference fitting portion 21c, the semiconductive portion 24a and the diameter difference fitting portion 21c become the insulating layer 140 of the power cable 100. Fit closely together. The semiconductive portion 24b covers the outer peripheral surface of the embedded pipe 23 except for a part (a portion 23a described later). The semiconductive portion 24 c covers the surface of the embedded flange 22 that is not exposed from the second insulator portion 21.

  The first insulator portion 20, the second insulator portion 21, the embedded flange 22, the embedded pipe 23, and the semiconductive portions 24a, 24b, and 24c constituting the polymer soot tube 2 are integrally formed by injection molding (mold molding). Molded.

  In addition, since the outer peripheral surface of the embedded pipe 23 is covered with the semiconductive portion 24c, even when a commercially available metal pipe is used as the embedded pipe 23, the electric field in the embedded pipe 23 is generated by the semiconductive portion 24c. Can be relaxed. Conversely, by making the outer peripheral surface of the embedded pipe 23 a smooth surface (for example, arithmetic average roughness Ra is 6.3 μm or less), electric field concentration on the outer peripheral surface of the embedded pipe 23 can be prevented, and the semiconductive portion 24c. Can be omitted.

<Configuration of other members>
As shown in FIG. 1, the protective metal fitting 3 consists of metal materials, such as a brass and an aluminum alloy, for example. The protective metal fitting 3 is attached to the housing 201 and the like together with the embedded flange 22 by, for example, a bolt 30.

  The conductor connection rod 4 is formed with a connection hole 4a having an opening on the rear end side of the polymer rod 2 and a male screw 4b protruding to the front end side. The conductor connecting rod 4 and the conductor 120 of the power cable 100 can be connected by inserting the conductor 120 of the power cable 100 into the connecting hole 4a of the conductor connecting rod 4 and caulking the opening of the conductor connecting rod 4. it can.

  Further, the fixed terminal 5 is formed with an insertion hole 5a for inserting the conductor connecting rod 4 and a connection hole 5b for connecting an electric wire (not shown). By inserting the conductor connecting rod 4 into the insertion hole 5a of the fixed terminal 5 and fastening the nut 40 to the male screw 4b, the fixed terminal 5 and the conductor connecting rod 4 can be connected. Moreover, the high voltage | pressure shield 6 consists of metal materials, such as a brass and an aluminum alloy, for example. The high-voltage shield 6 is formed in a cylindrical shape so as to cover the periphery of the conductor connecting rod 4.

  In addition, an exposed portion 23a exposed from the first insulator portion 20 is present on the distal end side of the polymer pipe 2 in the embedded pipe 23, and the high-pressure shield 6 is connected to the exposed portion 23a. The high voltage shield 6 is connected to the conductor 120 of the power cable 100 via the fixed terminal 5 and the conductor connecting rod 4. That is, the embedded pipe 23 has the same potential as the conductor 120 of the power cable 100.

  Thus, in Embodiment 1, since the embedded pipe 23 is embedded in the inner peripheral surface of the first insulator portion 20 and the embedded pipe 23 is connected to the conductor 120 of the power cable 100, the embedded pipe The space between 23 and the insulating layer 140 is a closed space. Therefore, it is not necessary to fill the space between the buried pipe 23 and the insulating layer 140 with an insulating material in order to prevent dielectric breakdown.

  Moreover, the waterproofing process part 7 is formed by winding the polyethylene tape which has an adhesion layer around the protective metal fitting 3 and the electric power cable 100, for example.

<Configuration of power cable>
FIG. 2 is a cross-sectional view of the power cable 100 connected to the termination connection portion 1a shown in FIG. As shown in FIG. 2, the power cable 100 includes a conductor 120 made of a stranded wire, an inner semiconductive layer 130 formed around the conductor 120, and an insulating layer 140 formed around the inner semiconductive layer 130. And an external semiconductive layer 150 formed around the insulating layer 140. In addition, the power cable 100 includes a shielding layer 170 formed around the outer semiconductive layer 150, a pressing tape layer 180 formed around the shielding layer 170, and a sheath layer formed around the pressing tape layer 180. 190.

  The conductor 120 is formed by twisting a plurality of strands. As this strand, for example, a wire such as a tin-plated annealed copper wire can be used. The conductor 120 transmits a high voltage of, for example, 6.6 kV to 500 kV.

  The inner semiconductive layer 130 and the outer semiconductive layer 150 are provided for relaxing the electric field. For example, the inner semiconductive layer 130 and the outer semiconductive layer 150 are made by dispersing conductive powder such as carbon in rubber such as ethylene propylene rubber (EPM), ethylene-vinyl acetate copolymer (EVA) resin, butyl rubber, etc. It is formed by extruding what is provided.

  The insulating layer 140 is formed, for example, by extruding a material such as ethylene propylene rubber (EPM), vinyl chloride, cross-linked polyethylene, silicone rubber, or a fluorine material.

  The shielding layer 170 is a so-called braided shield formed by winding a wire 171 around the outer semiconductive layer 150 along the axial direction of the power cable 100. The shielding layer 170 is connected to the ground potential when in use.

  The pressing tape layer 180 is formed by winding the pressing tape 181 around the shielding layer 170 in a spiral manner along the cable axial direction. For the presser tape 181, for example, a tape made of plastic or rayon having a thickness of 0.03 to 0.5 mm and a width of 50 to 90 mm can be used.

  The sheath layer 190 is formed, for example, by extruding rubber to which a crosslinking agent or the like is added. Examples of the rubber include natural rubber, butyl rubber, halogenated butyl rubber, ethylene propylene rubber, chloroprene rubber, styrene butadiene rubber, or nitrile rubber. Alternatively, examples of rubber include chlorosulfonated polyethylene, chlorinated polyethylene, epichlorobidin rubber, acrylic rubber, silicone rubber, fluororubber, urethane rubber, and non-halogen polyolefin elastomer.

<Background of study>
Here, items studied by the present inventor will be described. FIG. 7 shows a conventional example of a terminal connection portion using a polymer pipe. The terminal connection portion 1 d of the conventional example has a polymer soot tube 2. The polymer soot tube 2 includes an insulator 200 made of a polymer material such as silicone rubber. The insulator part 200 has a main body part 200a, a plurality of shade parts 200b provided around the main body part 200a, and a diameter difference fitting part 200c into which the end part 101 of the power cable 100 is inserted. The diameter difference fitting portion 200c has an inner diameter that is the same as or smaller than the outer diameter of the end portion 101 of the power cable 100 before the end portion 101 of the power cable 100 is inserted. Therefore, after the end portion 101 of the power cable 100 is inserted into the diameter difference fitting portion 200c, the diameter difference fitting portion 200c is brought into close contact with the end portion 101 of the power cable 100.

  As described above, since sufficient mechanical strength is required for the polymer soot tube, attention is paid to the deformation of the shade portion caused by the wind. Although the cap portion may be directly deformed by the wind, it is more often deformed by a vortex generated by the wind. In particular, when the frequency of the vortex generated by the wind and the natural frequency of the cap portion coincide with each other, the vortex and the cap portion resonate, and the deformation of the cap portion becomes the largest. Therefore, in order to examine the natural frequency of the cap, we will find the frequency of the vortex generated at the assumed maximum wind speed.

Assuming that the assumed maximum wind speed v is 139 m / s, the viscosity coefficient of air μ is 1.8 × 10 ⁻⁵ Pa · s, the density of air ρ is 1.2 kg / m ³ , and the representative dimension L is 40 mm. The number Re is obtained as Re = ρVL / μ = 3.7 × 10 ⁵ . Therefore, in the Karman vortex (a row of vortices that can alternate behind when an obstruction is placed in the flow or when a solid is moved in the fluid), the object, ie the terminal connection 1d, is assumed to be a cylinder. Sometimes, at this magnitude of the Reynolds number Re, the Strouhal number St is constant at about 0.2. Therefore, when the outer diameter D of the cylinder is 160 mm, the frequency f of the vortex is obtained as f = St × v / D≈173 Hz. Therefore, in order to prevent the cap portion from resonating within the assumed wind speed, it is desirable that the natural frequency of the cap portion is, for example, 200 Hz or more.

  From the above, in order to make the polymer soot pipe have sufficient mechanical strength, for example, the polymer material constituting the insulator part 200 is made so that the natural frequency of the cap part 200b of the polymer soot pipe 2 is 200 Hz or more. It is necessary to increase the elastic modulus (or hardness).

  However, if the elastic modulus (or hardness) of the polymer material constituting the insulator part 200 is increased, the insulator part 200 is not easily deformed, and the end 101 of the power cable 100 is inserted into the diameter difference fitting part 200c. It becomes difficult. As a result, there arises a problem that the workability of the termination connecting portion 1d is lowered. On the other hand, if the elastic modulus (or hardness) of the polymer material constituting the insulator portion 200 is lowered in order to prevent the workability of the end connection portion 1d from being lowered, the mechanical life of the end connection portion 1d is shortened. Electrical performance will be degraded.

  Therefore, instead of increasing the elastic modulus (or hardness) of the polymer material constituting the insulator part 200, the natural frequency of the shade part 200b is changed by changing the shape of the shade part 200b included in the insulator part 200. It is also conceivable to set the frequency to 200 Hz or higher. However, when the shape of the shade portion 200b is changed, the surface leakage distance and the shade distance between the insulator portions 200 are changed. When the surface leakage distance and the distance between the shades of the insulator 200 change, the electrical characteristics of the polymer soot tube 2 change, so the design change of the shade 200b is not realistic.

  Therefore, the present inventor has come up with the idea that the insulator part constituting the polymer soot tube is composed of two types of polymer materials having different elastic moduli (or hardness). As shown in FIG. 1, the polymer soot tube 2 according to the first embodiment includes a first insulator portion 20 and a second insulator portion 21 that are arranged along the insertion direction of the power cable 100. The second insulator portion 21 is made of a polymer material having an elastic modulus of 2 MPa or less, and the first insulator portion 20 is made of a polymer material having an elastic modulus higher than the material constituting the second insulator portion 21. Become.

  Here, in order to improve the workability of the terminal connection portion 1a using the polymer rod 2, the diameter difference fitting portion 21c into which the end portion 101 of the power cable 100 is inserted is made of a polymer material having an elastic modulus of 2 MPa or less. Must be configured. And in order to maintain the mechanical strength of the termination | terminus connection part 1a using the polymer soot pipe 2, in the 1st insulator part 20 and the 2nd insulator part 21 which comprise the polymer soot pipe 2, it is the 2nd insulator part 21. It is necessary to increase the component ratio of the first insulator portion 20 made of a polymer material having a higher elastic modulus than the material forming the. From the viewpoint of cost, it is desirable that the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding (molding). From the above viewpoint, optimization of the interface (bonding surface) between the first insulator portion 20 and the second insulator portion 21 constituting the polymer soot tube 2 becomes a problem.

  Here, in determining the interface between the first insulator portion 20 and the second insulator portion 21, first, an electric field generated in the insulator portion was considered. FIG. 3 is a schematic diagram showing the result of analyzing the equipotential surface (equipotential line) of the generated electric field in the enlarged vertical sectional view of the main part of the terminal connection portion shown in FIG.

  When the equipotential surface of the electric field generated in the termination connection portion 1a of the first embodiment was analyzed, the result shown in FIG. 3 was obtained. The embedded flange 22 and the semiconductive portion 24 a are at the ground potential, and the embedded pipe 23 is at the same potential as the conductor 120 of the power cable 100.

  As shown in FIG. 3, in the second insulator portion 21 (or the first insulator portion 20) located between the power cable 100 and the embedded pipe 23 and the embedded flange 22, the equipotential surfaces are spaced apart. Narrow and high electric field strength. Specifically, for example, when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100, the second insulator portion positioned between the power cable 100 and the embedded pipe 23 and the embedded flange 22. The electric field strength in 21 (or the first insulator portion 20) reaches 5 kV / mm.

  On the other hand, on the tip side of the polymer soot tube 2, that is, in the region where the embedded flange 22 does not exist, the equipotential surfaces are wide and the electric field strength is small. Note that the direction of the electric field is perpendicular to the equipotential surface.

  In general, when the interface of different materials and the direction of the electric field are perpendicular, the withstand voltage of the interface decreases, and dielectric breakdown is most likely to occur at this interface. On the other hand, when the interface of the different material and the direction of the electric field are parallel, the withstand voltage of the interface is hardly lowered, and the dielectric breakdown is hardly generated at this interface. Further, as a result of studies by the present inventors, it has been found that when the electric field strength at the interface of different materials exceeds 5 kV / mm, dielectric breakdown is likely to occur at this interface.

  Next, in determining the interface between the first insulator part 20 and the second insulator part 21, the elastic strain generated by an external force was considered. 4 is a schematic diagram showing a result of analyzing an elastic strain distribution generated by an external force in the enlarged vertical sectional view of the main part of the terminal connection portion shown in FIG.

  Consider the case where the terminal connecting portion 1a of the first embodiment causes the polymer soot tube 2 to vibrate due to wind, for example, and an elastic strain occurs in the first insulator portion 20 and the second insulator portion 21 constituting the polymer soot tube 2. When the elastic strain distribution generated at this time was analyzed, the result shown in FIG. 4 was obtained.

  As shown in FIG. 4, the elastic strain of the second insulator portion 21 (or the first insulator portion 20) located between the power cable 100 and the embedded pipe 23 and the embedded flange 22 is large. In particular, the elasticity of the end portion on the front end side of the polymer rod tube 2 in the cylindrical portion 22a of the embedded flange 22 and its peripheral region, and the end portion on the rear end side of the polymer rod tube 2 in the embedded pipe 23 and its peripheral region. Large distortion.

  When the interface between the different materials is located in a region where the elastic strain is large, the different materials are easily separated from each other, and the possibility that the electrical characteristics are deteriorated or the dielectric breakdown occurs is increased.

  Here, as shown in FIG. 1, a case where the interface between the first insulator part 20 and the second insulator part 21 is an interface 25d is considered as a first examination example. That is, with respect to the interface 25d, the leading end side of the polymer soot tube 2 is constituted by the first insulator portion 20, and the rear end side of the polymer soot tube is constituted by the second insulator portion 21. In this case, the diameter difference fitting portion 21c into which the end portion 101 of the power cable 100 is inserted can be constituted by the second insulator portion 21 made of a polymer material having an elastic modulus of 2 MPa or less. And the 1st insulator which consists of a polymeric material which has a higher elastic modulus than the material which comprises the 2nd insulator part 21 among the 1st insulator parts 20 and the 2nd insulator part 21 which comprise the polymer soot pipe 2 The component ratio of the part 20 can be increased most.

  However, referring to FIG. 3, the interface 25d shown in FIG. 1 is orthogonal to the direction of the electric field, and the electric field strength is high. Therefore, if the interface between the first insulator portion 20 and the second insulator portion 21 is the interface 25d, the possibility of dielectric breakdown occurring at the interface 25d increases.

  Further, referring to FIG. 4, it can be seen that the interface 25 d shown in FIG. 1 is located in a region where the elastic strain is large when the elastic strain is generated by an external force. Therefore, if the interface between the first insulator part 20 and the second insulator part 21 is the interface 25d, the first insulator part 20 and the second insulator part 21 are easily peeled off at the interface 25d, and the electrical characteristics are increased. There is a high possibility of a decrease in the thickness and dielectric breakdown.

  Moreover, as shown in FIG. 1, as a study example 2, a case where the interface between the first insulator part 20 and the second insulator part 21 includes the interface 25c (for example, the interfaces 25a and 25c) is considered. That is, with respect to the interfaces 25a and 25c, the leading end side of the polymer soot tube 2 is constituted by the first insulator portion 20, and the rear end side of the polymer soot tube is constituted by the second insulator portion 21. In this case, as can be seen with reference to FIG. 3, the interface 25a and the interface 25c are surfaces (shapes) along the equipotential surface (equipotential lines). By doing so, the interfaces 25a and 25c and the direction of the electric field can be made parallel. As a result, the possibility of dielectric breakdown occurring at the interfaces 25a and 25c between the first insulator portion 20 and the second insulator portion 21 can be reduced.

  However, referring to FIG. 4, it can be seen that the interface 25 c shown in FIG. 1 is located in a region having a large elastic strain when an elastic strain is generated in the polymer rod 2 due to an external force. Therefore, if the interface 25c is included in the interface between the first insulator part 20 and the second insulator part 21, the first insulator part 20 and the second insulator part 21 are easily peeled off at the interface 25c, and the electrical The possibility of deterioration of characteristics and dielectric breakdown increases.

  Further, Study Example 2 has another problem. As described above, the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding (molding). That is, after one resin material is poured into a mold and hardened, the other resin material is poured into the mold and hardened. At this time, if there is a portion where the gap between the mold and the already poured and hardened material is small, there is a possibility that a void is formed at that portion without filling the other material. In the case of injection molding of the polymer soot tube 2, since the resin material is poured along the axial direction of the polymer soot tube 2, in order to prevent the above-mentioned formation of the gap, the first insulator portion 20 and the second insulator portion 21 are used. It is desirable that the interface is perpendicular (orthogonal) to the axial direction of the polymer soot tube 2.

<Main features and effects of the first embodiment>
As shown in FIG. 1, one of the main features of the first embodiment is that a polymer insulator 2 is disposed along the insertion direction of the power cable 100, and a second insulator portion. The second insulator part 21 is made of a polymer material having an elastic modulus of 2 MPa or less, and the first insulator part 20 has a higher elastic modulus than the material constituting the second insulator part 21. It is made of a polymer material having And the 1st insulator part 20 is located in the front end side of the polymer soot pipe 2, and the 2nd insulator part 21 is located in the rear end side of the polymer soot pipe 2. As shown in FIG.

  By doing so, the shade portion 20b of the shade portions existing in the polymer soot tube 2 can be configured by the first insulator portion 20 made of a polymer material having a higher elastic modulus than the second insulator portion 21. it can. As a result, the natural frequency of the cap portion 20b can be set to 200 Hz or more, and the polymer soot tube can have sufficient mechanical strength.

  And the diameter difference fitting part 21c in which the edge part 101 of the electric power cable 100 is inserted can be comprised by the 2nd insulator part 21 which consists of a polymeric material which has an elastic modulus of 2 Mpa or less. As a result, it becomes easy to insert the end portion 101 of the power cable 100 into the diameter difference fitting portion 21c, and the workability of the terminal connection portion can be improved.

  Further, in the first embodiment, when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100, the first insulator portion 20 and the second insulator portion are arranged in a region where the electric field strength is 5 kV / mm or less. Interfaces 25a and 25b with 21 are formed. By doing so, the possibility of dielectric breakdown occurring at the interfaces 25a and 25b between the first insulator portion 20 and the second insulator portion 21 can be reduced.

  In particular, in the first embodiment, as can be seen by referring to FIG. 3, the interface 25a shown in FIG. 1 is a surface (shape) along the equipotential surface (equipotential line). Specifically, the interface 25a has a shape that narrows from the outer side to the inner side in the circumferential direction of the polymer soot tube 2 as it goes from the front end side to the rear end side of the polymer soot tube 2. By doing so, the interface 25a and the direction of the electric field can be made parallel. As a result, the possibility of dielectric breakdown occurring at the interface 25a between the first insulator portion 20 and the second insulator portion 21 can be further reduced.

  Further, in the first embodiment, as can be seen with reference to FIG. 4, the interface 25 b shown in FIG. 1 avoids a region having a large elastic strain when an elastic strain is generated in the polymer rod 2 by an external force. By doing so, the possibility that the first insulator portion 20 and the second insulator portion 21 are peeled off at the interface 25b can be reduced.

  Furthermore, as shown in FIG. 1, the interface 25 b is perpendicular to the axial direction of the polymer soot tube 2. By doing so, it is possible to prevent a gap from being formed when the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding.

  As described above, in the first embodiment, it is possible to provide an end connection portion that can achieve both improvement in mechanical strength and workability in the end connection portion using the polymer pipe.

  The interfaces 25a and 25b constitute the second insulator portion 21 of the first insulator portion 20 and the second insulator portion 21 that constitute the polymer rod pipe 2 in the direction closer to the rear end side of the polymer rod pipe 2. The constituent ratio of the first insulator portion 20 made of a polymer material having a higher elastic modulus than the material to be made can be increased. On the other hand, if the interfaces 25a and 25b are too close to the end portion of the cylindrical portion 22a of the embedded flange 22 on the distal end side of the polymer rod tube 2, as described above, the region 25a and 25b enter a region where a large elastic strain occurs. Therefore, it is preferable that the interfaces 25a and 25b are provided at a predetermined distance from the end portion on the distal end side of the polymer rod 2 in the cylindrical portion 22a of the embedded flange 22.

(Embodiment 2)
FIG. 5 is a longitudinal cross-sectional view showing a configuration example of a termination connecting portion according to a second embodiment (hereinafter referred to as a second embodiment) of the present invention. As shown in FIG. 5, in the terminal connection portion 1 b of the second embodiment, when a high voltage of 6.6 kV to 500 kV is transmitted through the power cable 100, the first electric field strength is 5 kV / mm or less. Interfaces 26 a and 26 b between the insulator part 20 and the second insulator part 21 are formed. As can be seen from FIG. 3, the interface 26a is mainly a plane (shape) along the equipotential plane (equipotential line). In particular, the interface 26 a of the second embodiment has a shape along the outer periphery of the cylindrical portion 22 a of the embedded flange 22 from the rear end side to the front end side of the polymer rod 2. The interface 26a has an elliptical shape that protrudes toward the distal end side of the polymer rod tube 2 in the vicinity of the end portion on the distal end side of the polymer rod tube 2 in the cylindrical portion 22a and goes from the circumferential outer side to the inner side of the polymer rod tube 2. Yes. This is the difference between the second embodiment and the first embodiment. The other configuration of the termination connection portion 1b of the second embodiment is the same as that of the termination connection portion 1a of the first embodiment, and a repeated description thereof is omitted.

  As described above, in the second embodiment, similarly to the first embodiment, when the high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100, the interface 26a is formed in a region where the electric field strength is 5 kV / mm or less. , 26b. By doing so, the possibility of dielectric breakdown occurring at the interfaces 26a and 26b between the first insulator portion 20 and the second insulator portion 21 can be reduced.

  The interface 26a of the second embodiment shown in FIG. 5 is a surface (shape) mainly along the equipotential surface (equipotential line). By doing so, the interface 26a and the direction of the electric field can be made parallel. As a result, the possibility of dielectric breakdown occurring at the interface 26a between the first insulator portion 20 and the second insulator portion 21 can be further reduced. In addition, the interface 26a has the interface length as long as possible even in a portion that is not parallel to the direction of the electric field, thereby reducing the electric field applied in the interface direction. Thereby, the possibility of dielectric breakdown occurring at the interface 26a can be reduced.

  Further, as can be seen from FIG. 4, the interface 26b of the second embodiment shown in FIG. 5 is similar to that of the first embodiment when the elastic strain is generated in the polymer rod 2 by an external force. Avoid large areas. As a reference example, FIG. 5 shows an interface 26c that goes from the interface 26a directly toward the inner side in the circumferential direction of the polymer pipe 2 along the equipotential surface. As shown in FIG. 26c is included in a region having a large elastic strain. By doing so, it is possible to reduce the possibility that the first insulator part 20 and the second insulator part 21 are peeled off at the interface 26b.

  Furthermore, as shown in FIG. 5, the interface 26 b is perpendicular to the axial direction of the polymer soot tube 2 as in the first embodiment. By doing so, it is possible to prevent a gap from being formed when the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding.

  As described above, in the second embodiment, similarly to the first embodiment, in the terminal connection portion using the polymer pipe, it is possible to provide a terminal connection portion that can achieve both improvement in mechanical strength and workability. .

  In particular, as shown in FIG. 5, the interface 26 a of the second embodiment has a shape along the outer periphery of the cylindrical portion 22 a of the embedded flange 22 from the rear end side to the front end side of the polymer rod 2. By doing so, it is possible to configure all the cap portions existing in the polymer soot tube 2 by the cap portions 20b including the first insulator portion 20 having a higher elastic modulus than the material constituting the second insulator portion 21. it can. Thereby, compared with the said Embodiment 1, the mechanical strength of the polymer soot tube 2 can be raised. In this respect, the second embodiment is more advantageous than the first embodiment.

  On the other hand, as can be seen with reference to FIG. 3, the interface 25a of the first embodiment shown in FIG. 1 has fewer regions across the equipotential surface than the interface 26a of the second embodiment shown in FIG. Therefore, the first embodiment is more advantageous than the second embodiment from the viewpoint of reducing dielectric breakdown at the interface of the insulator portion.

(Embodiment 3)
FIG. 6 is a longitudinal cross-sectional view showing a configuration example of a termination connecting portion according to a third embodiment (hereinafter referred to as a third embodiment) of the present invention. As shown in FIG. 6, in the terminal connection portion 1 c of the third embodiment, when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100, the first electric field strength is 5 kV / mm or less. Interfaces 27a and 27b between the insulator part 20 and the second insulator part 21 are formed. In particular, in the third embodiment, as can be seen with reference to FIG. 4, the interface 27a shown in FIG. 6 is shaped along the outside of the region where the elastic strain generated by the external force is large. Specifically, the interface 27a has a shape that narrows from the outer side to the inner side in the circumferential direction of the polymer soot tube 2 as it goes from the rear end side to the front end side of the polymer soot tube 2. This is the difference between the third embodiment and the first and second embodiments. Other configurations of the termination connection portion 1c of the third embodiment are the same as those of the termination connection portion 1a of the first embodiment and the termination connection portion 1b of the second embodiment, and repeated description is omitted.

  As described above, in the third embodiment, similarly to the first embodiment and the second embodiment, when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable 100, the electric field strength is 5 kV / mm or less. Interfaces 27a and 27b are formed in the regions. By doing so, the possibility of dielectric breakdown occurring at the interfaces 27a and 27b between the first insulator portion 20 and the second insulator portion 21 can be reduced.

  In addition, the interface 27a has an interface length as long as possible even in a portion that is not parallel to the direction of the electric field, thereby reducing the electric field applied in the interface direction. This can reduce the possibility of dielectric breakdown occurring at the interface 27a.

  And the interface 27a of Embodiment 3 shown in FIG. 6 is made into the shape in alignment with the outer side of the area | region where the elastic strain generated with an external force is large. By doing so, the possibility that the first insulator portion 20 and the second insulator portion 21 are peeled off at the interface 27a can be reduced.

  Furthermore, as shown in FIG. 6, the interface 27 b is perpendicular to the axial direction of the polymer soot tube 2, as in the first and second embodiments. By doing so, it is possible to prevent a gap from being formed when the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding.

  As described above, in the third embodiment, similarly to the first embodiment and the second embodiment, in the terminal connection portion using the polymer pipe, the terminal connection portion that can achieve both improvement in mechanical strength and workability. Can be provided.

  In particular, as can be seen with reference to FIG. 4, the interface 27a of the third embodiment shown in FIG. 6 is the interface 25a of the first embodiment shown in FIG. 1 and the interface 26a of the second embodiment shown in FIG. In comparison, there are few places included in the region where the elastic strain generated by the external force is large. Therefore, Embodiment 3 is more advantageous than Embodiment 1 and Embodiment 2 from the viewpoint of preventing the peeling of the insulator portion at the interface of the insulator portion.

  On the other hand, as can be seen by referring to FIG. 3, the interface 26a of the second embodiment shown in FIG. 5 has fewer places across the equipotential surface than the interface 27a of the third embodiment shown in FIG. Therefore, the second embodiment is more advantageous than the third embodiment from the viewpoint of reducing dielectric breakdown at the interface of the insulator portion. As described above, the first embodiment is most advantageous from the viewpoint of reducing the dielectric breakdown at the interface of the insulator portion.

  As a modification of the above-described third embodiment, the interface between the first insulator portion 20 and the second insulator portion 21 constituting the polymer rod 2 is directly from the circumferential outer side to the inner side of the polymer rod 2 from the interface 27a. The interfaces 27a and 27c may be included, including the interface 27c toward the surface. Unlike the interface 25c of the first embodiment shown in FIG. 1 and the interface 26c of the second embodiment shown in FIG. 5, the interface 27c of the third embodiment is not included in a region where a large elastic strain is generated. It is. However, from the viewpoint of preventing voids from being formed when the first insulator portion 20 and the second insulator portion 21 are integrally formed by injection molding, the axial direction of the polymer soot tube 2 is greater than that of the modified example. The third embodiment is more advantageous as the interfaces 27a and 27b including the interface 27b perpendicular to the surface.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 1 Conductor 1a, 1b, 1c, 1d Termination connection part 2 Polymer rod 2a, 2b Cable insertion hole 3 Protection metal fitting 4 Conductor connection rod 4a Connection hole 4b Male screw 5 Fixing terminal 5a Insertion hole 5b Connection hole 6 High pressure shield 7 Waterproof processing part DESCRIPTION OF SYMBOLS 10 Electric wire 20, 21 Insulator part 20a, 21a Main-body part 20b, 21b Cap part 21c Diameter difference fitting part 22 Embedded flange 22a Cylindrical part 22b Mounting part 22d Female thread 23 Embedded pipe 23a Exposed part 24a, 24b, 24c Semiconductive portion 25a, 25b, 25c, 25d Interface 26a, 26b, 26c Interface 27a, 27b, 27c Interface 30 Bolt 40 Nut 100 Power cable 101 End portion 120 Conductor 130 Internal semiconductive layer 140 Insulating layer 150 External semiconductive layer 170 Shielding layer 171 Wire 180 Pressing tape layer 181 Pressing tape 190 C Layer 200 insulator portion 200a body portion 200b cap portion 200c diameter difference fitting portion 201 housing

Claims (3)

A polymer main body having a cylindrical main body portion through which a power cable can be inserted and a cap portion provided around the main body portion,
The polymer pipe is composed of a first insulator portion and a second insulator portion arranged along the insertion direction of the power cable,
A diameter difference fitting portion into which an end of the power cable is inserted is formed in the second insulator portion,
The diameter difference fitting portion has the same or smaller inner diameter than the outer diameter of the end of the power cable before the end of the power cable is inserted,
The second insulator part is made of a polymer material having an elastic modulus of 2 MPa or less,
The first insulator part is made of a polymer material having a higher elastic modulus than the material constituting the second insulator part,
The natural frequency of the cap portion formed in the first insulator portion is 200 Hz or more,
The interface between the first insulator part and the second insulator part is formed in a region where the electric field strength is 5 kV / mm or less when a high voltage of 6.6 kV to 500 kV is transmitted by the power cable. The termination connection. In the terminal connection part according to claim 1,
The interface includes a termination connection including a surface along an equipotential surface. In the termination | terminus connection part of Claim 1,
The terminal interface includes a plane perpendicular to the axial direction of the polymer soot tube.

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