JP2023020320A - Cable end terminal connection part - Google Patents

Abstract

To provide a cable end terminal connection part which is preferably as an air end terminal connection part of a power cable of an ultra high pressure.SOLUTION: A cable end terminal connection part comprises: a porcelain tube; an insulation unit that includes a small diameter part on a tip end side and a large diameter part on a rear end side, and is arranged in the porcelain tube; a magnetic field relaxation part that is attached to the outer peripheral surface of the small diameter part; a fixing metal fitting that is arranged on the rear end side of the porcelain tube; an insulation medium that is sealed between the porcelain tube and the insulation unit; and a cable terminal part that is connected to the rear end side of the large diameter part. The insulation unit includes: an inner conductor extended to a shaft direction; a hard type insulation cylinder arranged on the outer peripheral surface of the inner conductor; a shielding part that is formed on the outer peripheral surface of the insulation cylinder so that the tip end is connected to the conductive part of the magnetic field relaxation part. The inner conductor is electrically connected to a conductive leading rod projected to the outer part so as to penetrate an upper metal fitting of the porcelain tube. The shielding part is formed at an intermediate position of the small diameter part from the large diameter part of the insulation unit, and the large diameter part is projected from the end part on the rear end side of the porcelain tube.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable termination connection, and more particularly to a technology suitable for an aerial termination of an ultra-high voltage power cable.

Conventionally, as a cable termination connection provided at the end of a power cable, an air termination connection that performs air insulation with a porcelain pipe is known (see, for example, Patent Documents 1 to 4), and is mainly prefabricated as a configuration. , rubber block type, and direct mold type.

In the cable termination connection portion disclosed in Patent Document 1, the conductor pull-out rod exposed at the tip side of the insulator is connected to the end of the cable conductor of the power cable by compression in the insulator, and is exposed by step stripping. A stress cone (also known as a pre-molded insulator), which is prefabricated at the factory for electric field mitigation, is attached to the power cable at the construction site on top of the cable insulation, thereby reducing the edge of the cable outer semiconducting layer. Field relaxation in the vicinity is realized. The stress cone is press-fixed by a compressing device against an epoxy seat inserted and fixed downward in the porcelain pipe. Air terminations of such construction are referred to as prefabricated. In a prefabricated aerial termination connection, generally, an insulating medium such as insulating oil (eg, silicone oil) is enclosed in a porcelain tube.

In the cable termination connection portion disclosed in Patent Documents 2 and 3, a conductor pull-out rod exposed at the tip side of the insulator is compression-connected to the end of the cable conductor of the power cable inside the insulator. In addition, on the cable insulation exposed by step stripping, a cold-shrink rubber block manufactured in advance at the factory is attached to the power cable at the construction site, so that the end of the cable outer semi-conductive layer Field relaxation in the vicinity is realized. This type of aerial termination does not have a compressing device for pressing the epoxy seat and stress cone in the porcelain pipe as in the above-mentioned prefabricated aerial termination. It is called a rubber block type because it has a structure that relaxes the electric field when placed at a specific position. The insulator used for the rubber block-shaped aerial termination connection may be either a porcelain insulator (see Patent Document 3) or a polymer insulator (also called a composite insulator, see Patent Document 2). An insulating medium such as oil (eg, silicone oil) is enclosed.

In the cable termination connection disclosed in Patent Document 4, an inner conductor, an insulating tube, and a polymer coating are integrally formed, and like the prefabricated air termination and the rubber block air termination, Never use oil or gas for insulation. Such an aerial termination connection of a completely dry solid insulation structure is called a direct mold type. In the direct mold type aerial termination connection part described in Patent Document 4, a cable end part to which a connection material such as a conductor connection terminal is attached is attached to a cable receiving part at the rear end of an insulating cylinder by plug-in connection. It has a plugin structure.

JP-A-2000-261948 Japanese Patent No. 5804948 Japanese Patent No. 4685908 JP 2017-184458 A

In the above-mentioned air-insulated porcelain-pipe-insulated aerial termination connection, the effective insulation length (the length of the porcelain-pipe main body where the cap is formed) is required to ensure insulation performance such as lightning impulse withstand voltage. is set. Therefore, when dealing with ultra-high voltage power cables, it is necessary to increase the length of the insulator. For example, in the case of a 275 kV class ultra-high voltage cable, a porcelain tube with a length of 3500 mm or more is required.

However, in the case of a prefabricated or rubber block type aerial termination connection, it is necessary to process the cable ends to approximately the same length as the porcelain pipe at the construction site. It will take longer and the construction time will be longer. In the case of a direct mold type aerial termination connection, the length of the insulation cylinder, which is a cast product, is increased in order to meet the effective insulation length required for ultra-high voltages. (Molding defects such as distortion and dents occurring on the surface) may occur, and the quality may deteriorate. As described above, it is difficult for the conventional aerial termination connection to cope with an ultra-high voltage power cable.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cable termination suitable as an aerial termination for ultra-high voltage power cables.

The cable termination connection part according to the present invention includes:
a porcelain pipe having a porcelain pipe main body having a cap portion formed on its outer peripheral surface, an upper metal fitting arranged on the front end side of the porcelain pipe main body, and a lower metal pipe arranged on the rear end side of the porcelain pipe main body;
A small diameter portion formed in a straight body shape on the tip side, an inclined portion whose diameter increases from the small diameter portion toward the rear end side, and a large diameter portion connected to the rear end side of the inclined portion and having an outer diameter larger than that of the small diameter portion. an insulation unit having a diameter portion and disposed within the insulator;
an electric field relaxation portion made of an elastic body attached to the outer peripheral surface of the small diameter portion and integrally formed with an insulating portion and a conductive portion connected to the rear end side of the insulating portion;
a fixing bracket disposed on the rear end side of the porcelain pipe;
an insulating medium enclosed between the insulator and the insulating unit;
a cable terminal portion connected to the rear end side of the large diameter portion,
The insulating unit includes an inner conductor extending in the axial direction, a hard insulating cylinder arranged on the outer peripheral surface of the inner conductor, and the insulating cylinder whose tip end is connected to the conductive part of the electric field relaxation part. and a shielding portion formed on the outer peripheral surface of the
The internal conductor is electrically connected to a conductor pull-out rod that penetrates the upper metal fitting and protrudes from the inside of the insulator tube to the outside,
the shielding portion is formed from the large-diameter portion of the insulating unit to an intermediate position of the small-diameter portion;
The large-diameter portion protrudes from the rear-end-side end portion of the insulator pipe.

ADVANTAGE OF THE INVENTION According to this invention, the cable termination connection part suitable as an air termination connection part of an ultra-high voltage power cable is provided.

FIG. 1 is a cross-sectional view showing a cable connecting portion according to an embodiment of the invention. FIG. 2 is an enlarged view of the periphery of the cable receiving portion. FIG. 3 is a diagram showing the relationship between the position of the electric field relaxation portion and the lightning impulse withstand voltage.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a cross-sectional view showing a cable terminal connector 1 according to an embodiment of the invention. FIG. 2 is an enlarged view of the periphery of the cable receiving portion 24 in the cable terminal connection portion 1. As shown in FIG.

As shown in FIGS. 1 and 2, the cable termination connection portion 1 includes a porcelain tube 10, an insulation unit 20, an electric field relaxation portion 30, a fixing bracket 41, a terminal fitting 42, an insulating medium 43, a conductor lead-out rod 44, and a cable. A terminal unit 50 and the like are provided. Hereinafter, the side from which the conductor pull-out rod 44 is pulled out will be referred to as the "front end side", and the side to which the cable terminal portion 50 is attached will be referred to as the "rear end side".

The insulator 10 includes a insulator main body 11 having a cap portion 11a formed on the outer peripheral surface, an upper metal fitting 12 arranged on the front end side of the insulator pipe main body 11, and a lower metal fitting 13 arranged on the rear end side of the insulator pipe main body 11. , has The porcelain insulator main body 11 may be, for example, a porcelain porcelain insulator, or may be a tubular body made of fiber reinforced plastics (FRP: Fiber Reinforced Plastics). It may also be a polymer insulator (also called a composite insulator). The length of the porcelain insulator main body 11, that is, the effective insulation length is set so as to satisfy the lightning impulse withstand voltage required for the cable end connection portion 1 .

The insulating unit 20 has an inner conductor 21 extending in the axial direction, an insulating tube 22 arranged on the outer peripheral surface of the inner conductor 21, and a shielding portion 23 formed on the outer peripheral surface of the insulating tube 22, It functions as a reinforcing insulation part for the cable termination connection part 1 . The internal conductor 21 and the insulating tube 22 are integrally formed by molding. The shielding portion 23 is formed, for example, by coating the outer peripheral surface of the insulating cylinder 22 with a conductive paint. The shielding portion 23 formed of the conductive paint applied to the outer peripheral surface of the insulating cylinder 22 is indicated by a thick line in FIG. 1 and by a broken line in FIG. In FIG. 2, the dashed line representing the shielding portion 23 (conductive paint) is displayed inside the solid line representing the insulating cylinder 22 for convenience of explanation in order to avoid overlapping with other lines and making it difficult to see.

The insulation unit 20 includes a small-diameter portion 20A formed in a straight body shape on the front end side, an inclined portion 20B that expands in diameter from the small-diameter portion 20A toward the rear end side, and a straight portion connected to the rear end side of the inclined portion 20B. It is divided into a trunk-shaped large-diameter portion 20C. The large diameter portion 20C has a larger outer diameter than the small diameter portion 20A. The insulating unit 20 is arranged such that the small diameter portion 20A is inside the insulator 10 and the large diameter portion 20C is outside the insulator 10. As shown in FIG. In this embodiment, the insulating unit 20 is arranged so that the rear end side of the inclined portion 20B is positioned at the rear end portion of the insulator 10 . Further, in the present embodiment, the distal end side of the small diameter portion 20A has a shape that decreases in diameter toward the distal end side. This makes it easier to insert the electric field relaxation portion 30 formed of a cylindrical elastic body, which will be described later, into the insulating unit 20 .

The internal conductor 21 is made of a conductive material suitable for conducting electricity, such as copper, aluminum, a copper alloy, or an aluminum alloy. The inner peripheral surface on the rear end side of the inner conductor 21 arranged in the large diameter portion 20C of the insulating unit 20 is exposed from the insulating tube 22, and the conductor insertion portion 21a for electrically connecting the cable conductor 511 is provided. is provided. The tip end of the internal conductor 21 penetrates the insulating tube 22 and is connected to the conductor pull-out rod 44 .

The insulating cylinder 22 is made of a hard plastic resin material (for example, epoxy resin or FRP) having high mechanical strength. A cone-shaped end insertion portion 22a for receiving the cable end portion 50 is provided on the rear end side of the insulating cylinder 22 arranged in the large diameter portion 20C of the insulating unit 20. As shown in FIG. The terminal inserting portion 22a communicates with the conductor inserting portion 21a of the internal conductor 21 . The conductor insertion portion 21a and the terminal insertion portion 22a form the cable receiving portion 24 to which the cable terminal portion 50 is attached.

In the present embodiment, the outer diameter of the large-diameter portion 20C of the insulation unit 20 (since the thickness of the shielding portion 23 is less than 1 mm, substantially the outer diameter of the rear end side of the insulating cylinder 22 located in the large-diameter portion 20C ) is set to be substantially the same as the inner diameter of the porcelain pipe 10 , but may be larger than the inner diameter of the porcelain pipe 10 . The large-diameter portion 20C of the insulation unit 20 in which the cable receiving portion 24 is formed is advantageous in designing the electric field to have a large outer diameter. Since the large-diameter portion 20C of the insulating unit 20 is arranged outside the insulator 10, it can be designed to have an outer diameter suitable for electric field design without being restricted by the inner diameter of the insulator 10.

Further, the insulating cylinder 22 is formed in an R shape at the inclined portion 20B of the insulating unit 20 so as to gradually taper from the large diameter portion 20C toward the small diameter portion 20A. That is, the outer shape of the insulating cylinder 22 is a shape without electrical protrusions that induce electric field concentration. As a result, even when the shielding portion 23 is formed on the outer peripheral surface of the insulating tube 22 at the inclined portion 20B of the insulating unit 20, the electric field does not concentrate between the inner conductor 21 and the shielding portion 23, and the insulating tube 22 is The internal electric field can be made uniform.

The shielding portion 23 is formed on the outer peripheral surface of the insulating cylinder 22 from the rear end of the large-diameter portion 20C of the insulating unit 20 to the intermediate position of the small-diameter portion 20A. The position of the intermediate position is not particularly limited as long as it is in the middle of the small diameter portion 20A in the longitudinal direction. By providing the shielding portion 23, the electric field is not concentrated between the inner conductor 21 and the shielding portion 23, the electric field inside the insulating cylinder 22 is made uniform, and the electrical characteristics are stabilized.

The electric field relaxation portion 30 is formed of a cylindrical elastic body having an insulating portion 31 on the front end side and a conductive portion 32 on the rear end side. The insulating portion 31 is concentrically connected to the conductive portion 32 at its rear end side, and is formed in a cylindrical shape from an insulating rubber material such as ethylene propylene rubber (EP rubber), for example. The conductive portion 32 has a bellmouth-like curved shape at the distal end, which gradually expands in diameter from the inner peripheral portion near the distal end toward the distal end. The conductive portion 32 is formed in a cylindrical shape from a semi-conductive rubber material such as semi-conductive EP rubber. It is connected to the insulating portion 31 at a portion extending to the vicinity thereof. The inner peripheral portion of the conductive portion 32 is exposed as the inner peripheral surface of the electric field relaxation portion 30 except for the tip end portion integrated with the insulating portion 31 , and communicates with the inner peripheral surface of the insulating portion 31 . The insulating portion 31 and the conductive portion 32 are integrally formed by molding. In the embodiment of FIG. 1, the outer shape of the electric field relaxation portion 30 is a cylindrical shape in which the rear end side of the conductive portion 32 is exposed, but the shape of the outer shape is not particularly limited.

The electric field relaxation portion 30 is arranged on the outer peripheral surface of the small diameter portion 20A of the insulation unit 20 . Specifically, the electric field relaxation portion 30 overlaps the inner peripheral surface of the conductive portion 32 and the shielding portion 23 so as to be electrically connected, and the tip of the shielding portion 23 does not protrude from the inner peripheral surface of the conductive portion 32. placed. The electric field relaxation portion 30 suppresses electric field concentration at the tip of the shielding portion 23 and relieves electrical stress applied to the insulating cylinder 22 .

Here, when the tip position of the conductive portion 32 in the axial direction changes, the electric field appearing on the surface of the insulator 10 changes and affects the surface flashover. need to be In the present embodiment, the tip position of the conductive portion 32 is set so that the distance from the rear end of the insulator main body 11 is 10 to 27% of the insulation effective length of the insulator main body 11 . As shown in FIG. 3, the lightning impulse withstand voltage varies depending on the tip position of the conductive portion 32 . Specifically, based on the lightning impulse withstand voltage when the distance from the rear end of the insulator main body 11 to the tip position of the conductive portion 32 is about 21% of the length of the insulator main body 11, the insulator As the distance from the rear end of the main body 11 to the tip position of the conductive portion 32 increases or decreases, the lightning impulse withstand voltage decreases. 3, when the distance from the rear end of the insulator main body 11 to the tip position of the conductive part 32 is 10 to 27% of the insulation effective length of the insulator main body 11, the reduction rate of the lightning impulse withstand voltage is can be suppressed to 10% or less. Further, when the distance from the rear end of the insulator main body 11 to the tip position of the conductive part 32 is 11 to 18% or 20 to 24% of the effective insulation length of the insulator main body 11, the lightning impulse withstand voltage It can be seen that the reduction rate can be suppressed to 5% or less, which is more preferable. Specifically, when the distance from the rear end of the insulator main body 11 to the tip position of the conductive portion 32 is 11 to 18% of the effective insulation length of the insulator main body 11, the reduction rate of the lightning impulse withstand voltage is It can be seen that the reduction rate of the lightning impulse withstand voltage can be suppressed between 1 and 5%, and when it is 20 to 24% of the insulation effective length of the porcelain tube main body 11, the reduction rate of the lightning impulse withstand voltage can be suppressed between 0 and 5%. In this embodiment, the best lightning impulse withstand voltage performance is obtained when the distance from the rear end of the insulator main body 11 to the tip position of the conductive portion 32 is about 21% of the effective insulation length of the insulator main body 11. Most preferred. The position of the tip side of the shielding portion 23 is appropriately set within the above range while maintaining the overlap with the conductive portion 32 of the electric field relaxation portion 30 .

The fixture 41 is a flange-like member having an opening equivalent to the large diameter portion 20C of the insulation unit 20. As shown in FIG. The fixing metal fitting 41 is arranged on the rear end side of the insulator pipe 10 and is fastened to the lower metal fitting 13 of the insulator pipe 10 by, for example, bolting. A support insulator 45 is arranged on the rear end side of the fixing bracket 41 and is fastened by, for example, bolting.

The terminal fitting 42 is a bottomed cylindrical member having an inner diameter equal to that of the large-diameter portion 20C of the insulating unit 20 . A bottom portion 42a of the terminal fitting 42 is provided with an opening 42b into which the cable terminal portion 50 is inserted. The terminal mounting bracket 42 is arranged on the rear end side of the fixing bracket 41 and is fastened to the fixing bracket 41 and the insulating unit 20 by, for example, bolting.

The inner diameters of the fixing bracket 41 and the terminal mounting bracket 42 are formed to have substantially the same diameter as the outer diameter of the large-diameter portion 20C of the insulating unit 20, and a sealing member such as an O-ring is provided between the fixing bracket 41 and the insulating unit 20. 46 are arranged. A plurality of sealing members 46 are preferably provided at predetermined intervals in the axial direction. As a result, the inside of the insulator 10 can be kept airtight or liquid-tight to prevent the insulating medium 43 from leaking, and the bending stress generated in the insulator 10 can be alleviated.

The insulating medium 43 is enclosed in the space between the porcelain tube 10 and the insulating unit 20 and functions as the main insulation of the cable termination 1 . The insulating medium 43 is made of a liquid insulating medium such as silicone oil. The insulating medium 43 may be an insulating material such as silicone gel or silicone rubber that hardens after being injected.

The insulating medium 43 is injected into the insulator 10 through, for example, a channel 41 a provided in the fixture 41 . In this case, it is preferable that the fixture 41 is provided with a counterbore 41b around the outlet of the flow path 41a. Moreover, it is preferable that the outer diameter of the insulating unit 20 near the outlet of the flow path 41 a is sufficiently smaller than the inner diameter of the insulator 10 . As a result, the insulating medium 43 can be injected into the insulator 10 at a sufficient flow rate without obstructing the flow of the insulating medium 43 injected through the flow path 41a.

The rear end of the conductor pull-out rod 44 is connected to the inner conductor 21 of the insulating unit 20, and the front end thereof penetrates the upper metal fitting 12 of the insulator 10 and is drawn out. In other words, the inner conductor 21 is electrically connected to the conductor lead-out rod 44 that penetrates the upper metal fitting 12 and protrudes from the inside of the insulator 10 to the outside. The conductor pull-out bar 44 is connected with the inner conductor 21 of the insulating unit 20 via, for example, a suitable conductor connecting member. Also, the portion of the conductor pull-out rod 44 that is disposed inside the insulator tube 10 may be a flexible conductor such as a cable. In this case, the leading end of the cable is connected to the rear end of the conductor rod that passes through the upper metal fitting 12 and is pulled out to the outside. is formed. By constructing the portion of the conductor pull-out rod 44 that is placed inside the insulator 10 with a cable, the flexible cable absorbs the bending stress that occurs in the insulator 10, causing excessive stress to the internal insulation unit 20. You can prevent it from happening. Also, by applying a cable covered with an insulating coating, the electric field generated on the surface of the conductor pull-out rod 44 can be suppressed.

Here, "the internal conductor is electrically connected to the conductor pull-out rod that penetrates the upper metal fitting and protrudes from the inside of the porcelain insulator to the outside" means that the conductor pull-out rod 44 and the internal conductor 21 It includes not only the case where the inner conductor is formed from a separate member, but also the case where the conductor pull-out bar is formed from the same member by lengthening the inner conductor. In other words, the internal conductor 21 may be elongated so that the internal conductor 21 is pulled out from the upper metal fitting 12 . In this case, the inner conductor 21 and the conductor lead-out bar 44 are formed of the same member, and the conductor lead-out bar 44 as a separate member from the inner conductor 21 is not required, but the inner conductor also functions as a conductor lead-out bar. do.

The cable terminal portion 50 is configured by attaching connection materials such as a conductor connection terminal 52 , a stress cone 53 , and a compression device 54 to the tip portion of a power cable 51 .

The power cable 51 is, for example, a 275 kV class extra-high voltage power cable insulated with rubber or plastic. The power cable 51 has, in order from the center, a cable conductor 511, a cable insulator 512, a cable outer semi-conductive layer 513, a cable shielding layer 514, a cable sheath 515, and the like. At the cable end portion 50, each layer is exposed by step-stripping from the tip portion of the power cable 51 by a predetermined length.

A conductor connection terminal 52 is connected to the tip of the cable conductor 511 by compression. The conductor connection terminal 52 is made of a conductive material suitable for conducting electricity, such as copper, aluminum, a copper alloy, or an aluminum alloy. A stress cone 53 is attached to the outer peripheral surface extending from the cable insulator 512 to the tip of the cable outer semiconductive layer 513 .

The stress cone 53 is formed in a fusiform shape and, like the electric field relaxation section 30, has an insulating portion (reference numerals omitted) on the front end side and a conductive portion (reference numerals omitted) on the rear end side. The insulating portion is formed in a cylindrical shape from an insulating rubber material such as EP rubber, and the conductive portion is formed in a cylindrical shape from a semi-conductive rubber material such as semi-conductive EP rubber. The insulating portion and the conductive portion are integrally formed by molding.

A rear end portion (semiconductive portion) of the stress cone 53 is connected to the cable outer semiconductive layer 513 of the power cable 51 . "Connected to the cable outer semi-conductive layer 513 of the power cable 51" means that the cable outer semi-conductive layer 513 is directly connected to the cable outer semi-conductive layer 513 as long as it has a predetermined performance as a cable termination connection. is connected to the end of the external semiconducting layer through a mold or an end of the outer semiconducting layer reproduced with conductive paint. The tip (insulating portion) of the stress cone 53 has a shape corresponding to the cable receiving portion 24 of the insulating unit 20 . A compressing device 54 and a protective fitting 55 are attached to the rear end side of the stress cone 53 .

The compression device 54 includes a pressing metal fitting (reference numerals omitted) that abuts on the stress cone 53, a coil spring (reference numerals omitted) that biases the pressing metal fittings toward the stress cone 53, and a pressing metal fitting flange that supports the pressing metal fittings and the coil springs. (reference numerals omitted).

After stripping the tip of the power cable 51 , the protective fitting 55 , the compressing device 54 and the stress cone 53 are inserted into the power cable 51 , and the conductor connection terminal 52 is attached to the cable conductor 511 . Then, the tip of the cable end portion 50 is inserted into the cable receiving portion 24 of the insulation unit 20, and while compressing the coil spring of the compression device 54, the pressing metal flange is bolted to the bottom portion 42a of the terminal mounting metal 42 for protection. The cable end 50 is attached to the cable receiving portion 24 by bolting the fitting 55 to the push fitting flange.
The tip of the stress cone 53 is pressed against the inner surface of the insulating cylinder 22 , and the conductor connection terminal 52 is electrically connected to the conductor insertion portion 21 a of the internal conductor 21 . A corrosion-resistant layer (reference numerals omitted) for waterproofing is arranged at the rear end portion of the protective fitting 55 . In this way, the cable termination connection portion 1 can be assembled with relatively simple work by plug-in connection.

In this manner, the cable termination connection portion 1 includes the insulator main body 11 having the cap portion 11a formed on the outer peripheral surface, the upper metal fitting 12 arranged on the front end side of the insulator pipe main body 11, and the insulator pipe main body 11 arranged on the rear end side of the insulator pipe main body 11. A porcelain pipe 10 having a lower metal fitting 13, a small diameter portion 20A formed in a straight barrel shape on the front end side, an inclined portion 20B expanding in diameter from the small diameter portion 20A toward the rear end side, and a rear end side of the inclined portion 20B The insulating unit 20, which has a large diameter portion 20C which is connected and has an outer diameter larger than that of the small diameter portion 20A, is arranged in the insulator 10, and the insulating portion 31 and the insulating portion 31 are attached to the outer peripheral surface of the small diameter portion 20A. An electric field relaxation part 30 made of an elastic body integrally formed with a conductive part 32 continuously provided on the rear end side, a fixing metal fitting 41 arranged on the rear end side of the insulator 10, the insulator 10 and the insulation unit 20. and a cable end portion 50 connected to the rear end side of the large diameter portion 20C. The insulating unit 20 includes an inner conductor 21 extending in the axial direction, a hard insulating cylinder 22 arranged on the outer peripheral surface of the inner conductor 21, and an insulating end connected to the conductive portion 32 of the electric field relaxation portion 30. and a shielding portion 23 formed on the outer peripheral surface of the tube 22 . The inner conductor 21 is electrically connected to a conductor lead-out rod 44 that penetrates the upper metal fitting 12 and protrudes from the inside of the insulator 10 to the outside. The shielding portion 23 is formed from the large-diameter portion 20C of the insulation unit 20 to the intermediate position of the small-diameter portion 20A, and the large-diameter portion 20C protrudes from the rear end of the insulator 10 .

According to the cable termination connection section 1, the insulating medium 43, which is the main insulation section, and the insulation unit 20, which is the reinforcement insulation section, are configured to ensure the insulation performance at the cable termination. Since the insulator tube 10 can be lengthened without modification, the quality of the insulating cylinder 22, which is a casting product, does not deteriorate with the lengthening of the insulator tube 10.例文帳に追加In addition, since the insulation unit 20 is manufactured in a factory, construction time on site can be shortened. Furthermore, since the connection position between the cable terminal portion 50 and the insulation unit 20 is provided at a position protruding from the rear end portion of the insulator 10, the length of the terminal processing of the power cable 51 can be increased even if the insulator 10 is lengthened. No need. Therefore, the cable termination connection portion 1 can easily cope with the ultra-high voltage of the power cable 51, and is suitable as an aerial termination connection portion for ultra-high voltage power cables.

Further, in the cable terminal connection portion 1, the cable terminal portion 50 is attached by plug-in connection to the cable receiving portion 24 provided on the rear end side of the large diameter portion 20C.
By adopting a structure in which the cable end portion 50 is connected to the insulation unit 20 by plug-in connection, the insulating medium 43 can be injected in advance into the insulator 10 at the factory, and the amount of the insulating medium 43 can be adjusted to a predetermined amount at the site. , there is no need to inject the insulating medium 43 from scratch at the site, and the construction time at the site can be greatly shortened.

In the cable termination connection portion 1 , the electric field relaxation portion 30 has a distance of 10 times the length of the insulator main body 11 (insulation effective length) from the rear end of the insulator main body 11 to the tip position of the conductive portion 32 . It is arranged at a position of ~27%. Preferably, the electric field relaxation part 30 is positioned such that the distance from the rear end of the insulator main body 11 to the tip position of the conductive part 32 is 11 to 18% or 20 to 24% of the length of the insulator main body 11. placed in
As a result, when the length of the porcelain pipe 10 is designed so as to satisfy the lightning impulse withstand voltage required for the cable end connection portion 1, the lightning impulse withstand voltage characteristic varies depending on the tip position of the conductive portion 32 of the electric field relaxation portion 30. Remarkable deterioration can be suppressed, and desired insulation performance can be secured.

In addition, in the cable terminal connection portion 1, a sealing member 46 is interposed between the fixing bracket 41 and the large diameter portion 20C. Specifically, a plurality of sealing members 46 are arranged along the axial direction.
As a result, the inside of the insulator 10 can be kept airtight or liquid-tight to prevent the insulating medium 43 from leaking, and the bending stress generated in the insulator 10 can be absorbed.

Moreover, in the cable terminal connection portion 1, at least a portion of the portion of the conductor pull-out rod 44 disposed inside the porcelain tube 10 is formed of a cable.
As a result, the bending stress generated in the porcelain pipe 10 can be absorbed by the flexible cable, and excessive stress can be prevented from being generated in the internal insulation unit 20 . Also, by applying a cable covered with an insulating coating, the electric field generated on the surface of the conductor pull-out rod 44 can be suppressed.

Moreover, in the cable terminal connection portion 1 , the fixture 41 has a channel 41 a through which an insulating medium 43 can be injected into the insulator 10 . Specifically, the flow path 41a has an outlet port communicating with the inside of the insulator 10 at a position corresponding to the inclined portion 20B of the insulating unit 20. , in other words, near the transition portion from the large diameter portion 20C toward the small diameter portion 20A.
As a result, the insulating medium 43 can be injected into the porcelain pipe 10 through the flow path 41a, and the insulating medium 43 is injected in advance at the factory, and the appropriate amount is removed at the construction site to set the predetermined amount. can also If the flow path 41a is not provided in the fixture 41, the insulating medium 43 is injected from the upper portion of the porcelain pipe 10, so a member is required to secure a foothold during high-place work at the construction site. Problems arise in terms of safety. By providing the flow path 41a in the fixture 41, the insulating medium 43 can be easily and safely set to an appropriate amount while the cable termination portion 1 is installed at the construction site.

In addition, in the cable termination connection portion 1, a counterbore 41b is formed around the lead-out port of the fixture 41. As shown in FIG.
As a result, the insulating medium 43 can be injected into the insulator 10 at a sufficient flow rate without obstructing the flow of the insulating medium 43 injected through the flow path 41a.

Although the invention made by the inventor of the present invention has been specifically described above based on the embodiments, the present invention is not limited to the above embodiments, and can be changed without departing from the scope of the invention.

For example, in the present embodiment, the insulating medium 43 is made of a liquid insulating medium, but may be made of an insulating gas. In this case also, the same effect as described above can be obtained.
In addition, in the present embodiment, the case of plug-in connecting the cable end portion with an inner cone type having a stress cone, a compression device, etc. was explained, but the cable end portion and the insulation unit are connected with a rubber block with an outer cone type. may be connected. In this case, a large-diameter portion 20C is formed at a position corresponding to the fixing bracket 41 of the insulating unit 20 as in the present embodiment, but a rubber block is connected to the rear end side of the insulating cylinder. Therefore, the rear end portion of the insulating tube is not a cable receiving opening like an inner cone type, but a shape in which the insulating tube protrudes, and the inner conductor protrudes from the rear end portion of the insulating tube.

It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the meaning and range of equivalents of the scope of the claims.

Reference Signs List 1 cable termination connection portion 10 porcelain pipe 11 porcelain pipe main body 12 upper metal fitting 13 lower metal fitting 20 insulation unit 20A small diameter portion 20B inclined portion 20C large diameter portion 21 inner conductor 22 insulating tube 23 shielding portion 24 cable receiving portion 30 electric field relaxation portion 31 insulating portion 32 Electrically Conducting Part 41 Fixing Bracket 42 Terminal Mounting Bracket 43 Insulating Medium 44 Conductor Drawing Rod 50 Cable Terminal Part

Claims (10)

a porcelain pipe having a porcelain pipe main body having a cap portion formed on its outer peripheral surface, an upper metal fitting arranged on the front end side of the porcelain pipe main body, and a lower metal pipe arranged on the rear end side of the porcelain pipe main body;
A small diameter portion formed in a straight body shape on the tip side, an inclined portion whose diameter increases from the small diameter portion toward the rear end side, and a large diameter portion connected to the rear end side of the inclined portion and having an outer diameter larger than that of the small diameter portion. an insulation unit having a diameter portion and disposed within the insulator;
an electric field relaxation portion made of an elastic body attached to the outer peripheral surface of the small diameter portion and integrally formed with an insulating portion and a conductive portion connected to the rear end side of the insulating portion;
a fixing bracket disposed on the rear end side of the porcelain pipe;
an insulating medium enclosed between the insulator and the insulating unit;
a cable terminal portion connected to the rear end side of the large diameter portion,
The insulating unit includes an inner conductor extending in the axial direction, a hard insulating cylinder arranged on the outer peripheral surface of the inner conductor, and the insulating cylinder whose tip end is connected to the conductive part of the electric field relaxation part. and a shielding portion formed on the outer peripheral surface of the
The internal conductor is electrically connected to a conductor pull-out rod that penetrates the upper metal fitting and protrudes from the inside of the insulator tube to the outside,
the shielding portion is formed from the large-diameter portion of the insulating unit to an intermediate position of the small-diameter portion;
The large-diameter portion protrudes from the rear end of the porcelain insulator,
Cable termination connection. The cable end portion is attached to a cable receiving portion provided on the rear end side of the large diameter portion by plug-in connection.
2. A cable termination connection as claimed in claim 1. A sealing member is interposed between the fixing bracket and the large-diameter portion,
3. Cable terminating connection according to claim 1 or 2. The electric field relaxation part is arranged at a position where the distance from the end on the rear end side of the insulator main body to the tip position of the conductive part is 10 to 27% of the length of the insulator main body,
Cable termination according to any one of claims 1-3. The electric field relaxation part is arranged at a position where the distance from the end on the rear end side of the insulator main body to the tip position of the conductive part is 11 to 18% or 20 to 24% of the length of the insulator main body. ing,
5. A cable termination connection according to claim 4. At least a portion of the portion of the conductor pull-out rod disposed within the insulator tube is formed of a cable,
Cable termination according to any one of claims 1 to 5. The fixture has a channel into which the insulating medium can be injected into the insulator,
Cable termination according to any one of claims 1-6. The flow path is provided such that an outlet to the inside of the insulator is located on the outer periphery of the inclined portion.
8. A cable termination connection according to claim 7. A counterbore is formed around the outlet of the fixture,
9. A cable termination connection according to claim 8. The insulating unit is formed in an R shape at the inclined portion so as to gradually taper from the large diameter portion toward the small diameter portion.
Cable termination according to any one of claims 1-9.

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