JP4659773B2 - Cable termination connection - Google Patents

Description

  The present invention relates to a cable termination connection portion, and more particularly to a cable termination connection portion in which a cable conductor connection end portion having a current-carrying portion is plug-in connected to a conductor insertion hole provided in a lower end portion of an internal conductor.

  Conventionally, as this kind of cable terminal connection portion, as shown in FIG. 2, a small-sized epoxy bushing 200 is airtightly attached to the opening 110 of the device case 100, and the cable is connected to the receiving port 210 of the epoxy bushing 200. A device that is equipped with a terminal 300 is known (see, for example, Patent Document 1).

  Here, the epoxy bushing 200 has a bullet-shaped head 220 at the tip, and an inner conductor 400 having a conductor insertion hole 410 at the lower end is embedded in the center of the head 220. The conductor insertion hole 410 is plug-in connected with a cable conductor connection end portion 500 having an energization portion 510 and a retaining portion 520.

By the way, in the cable termination connection portion having such a configuration, as a method of mounting a large-sized cable terminal portion 300, for example, a high-voltage CV cable end portion having a conductor size of 600 mm ² or more, (a) FIG. (B) a method of increasing the thickness of the inner conductor 400 as shown in FIG. 4, (c) a method of increasing the inner conductor 400 and the epoxy bushing as shown in FIG. A method of securing current carrying capacity and insulation thickness by making both 200 thick can be considered, but each has the following drawbacks.

That is, in the method (a) in which the conductor insertion hole 410 of the inner conductor 400 is enlarged, the thickness t ₁ of the inner conductor 400 corresponding to the energizing portion 510 is reduced, and the energizing capacity may be insufficient at the plug-in connecting portion. There is. For this reason, if a predetermined current is passed through the cable conductor connection end portion 500 in this state, heat is generated at the portion where the thickness t ₁ is thin, and the insulation characteristics of the epoxy bushing 200 may be deteriorated. In the method of thickening the inner conductor 400 of (b), the insulating thickness t ₂ of the epoxy bushing 200 is thinner, the electric field of the interface becomes uneven, consequently epoxy bushing 200 is liable to breakdown. Furthermore, in the method (C) in which both the inner conductor 400 and the epoxy bushing 200 are both thickened, the cable terminal connection portion is enlarged, and consequently the electric equipment is enlarged.

JP 2005-192283 A

The present invention has been made to solve the above-mentioned problems, and even if the conductor size of the cable terminal attached to the bushing is, for example, a large size cable of 600 mm ² or more, there is a possibility that heat is generated at the plug-in connection portion. Therefore, an object of the present invention is to provide a cable terminal connection portion that does not deteriorate the insulation characteristics of the bushing.

The cable termination connecting portion according to the first aspect of the present invention includes a bushing having an inner conductor at the center of the tip and a receiving end of the cable end at the lower end, and an insulating portion having rubber-like elasticity at the receiving end of the bushing. A conductor having a cable end fitted with a stress cone made of a semiconductive portion and having a current-carrying portion plug-in connected to a conductor insertion hole provided in a lower end portion of the internal conductor In the cable termination connection portion for a large cable having a size of 600 mm ² or more , the inner conductor is connected to the large diameter portion protruding from the top of the bushing and the rear end portion side of the large diameter portion via the neck portion. The tip has a small diameter part concentrically embedded with the bushing , the neck part exists at a position corresponding to the top part of the bushing, the outer diameter of the neck part is smaller than the outer diameter of the small diameter part, and the large diameter part The outer diameter of the small-diameter portion is larger than the outer diameter of the small-diameter portion, and a circular conductor insertion hole is provided in the inner conductor from the lower end portion of the small-diameter portion to the large-diameter portion. It is arrange | positioned in the position corresponding to a diameter part.

According to a second aspect of the present invention, in the cable termination connecting portion according to the first aspect, a cable conductor connecting end portion is provided with a retaining portion on a lower side than the energizing portion.

According to a third aspect of the present invention, in the cable termination connection portion according to the first aspect or the second aspect, the retaining portion includes a first retaining means and a second retaining means, and the conductor insertion hole is The first and second retaining means are provided with storage grooves at positions corresponding to the first and second retaining means, and the first and second retaining means are spaced apart from each other along the longitudinal direction of the conductor insertion hole. It is what.

  According to the cable termination connecting portion of the present invention, since the energizing portion is located above the top of the bushing, the plug-in connecting portion can be obtained by increasing the outer diameter of the inner conductor at a position corresponding to the energizing portion. Can provide a desired current carrying capacity, and thus can provide a cable termination connection portion that does not deteriorate the insulation characteristics of the bushing, and can increase the diameter of the inner conductor protruding from the top of the bushing. Since the electric field does not wrap around the triple junction (triple junction) where the bushing (insulator such as epoxy resin) and the gas insulation in the equipment case and the internal conductor are in contact, partial discharge may occur at the triple junction. Disappear. Further, when the cable conductor connecting end portion uses the retaining portion having the first and second retaining means, the cable conductor can be reliably gripped even with a large size cable.

  Hereinafter, a preferred embodiment to which the cable termination connecting portion of the present invention is applied will be described with reference to the drawings. In the following description, the “tip portion” of the bushing, the internal conductor, the energizing portion, the retaining portion, and the cable conductor connecting end portion refers to the upward direction in the figure, and the bushing, the inner conductor, the energizing portion, the retaining portion The “rear end” of the cable conductor connection end and the cable conductor connection end means the end opposite to the front end and corresponds to the downward direction in the drawing.

FIG. 1 shows a longitudinal cross-sectional view of a terminal termination part in gas of a 66 to 77 kV class CV cable (single core 2000 mm ² ) to which the cable termination connection part of the present invention is applied.

  In the figure, the end-of-gas connecting portion in the present invention includes a device case 1 for airtightly storing power devices (not shown) such as switches and transformers, and a tip portion in the device case 1. A bushing 2 that is positioned and hermetically attached to the peripheral edge of the opening 11 of the device case 1 so as to close the opening 11, a cable terminal 3 mounted in the bushing 2, and a cable terminal And an annular pressing device 5 that presses the stress cone 4 inserted and inserted in the axial direction toward the distal end side of the bushing 2.

  The bushing 2 includes a bullet-shaped head portion 21 provided at the front end portion, a cylindrical portion 23 connected to the rear end portion side of the head portion 21 via an electric field relaxation portion 22, an electric field relaxation portion 22 and a cylindrical portion. And a flange portion 24 provided so as to protrude in the radial direction on the outer periphery of the head portion 23, and the head portion 21 is successively reduced in diameter from the tip portion of the cylindrical portion 23 toward the top portion 21 a of the head portion 21. A tapered receiving port 25 is provided so as to be concentric with the cylindrical portion 23 and communicate with the cylindrical portion 23.

  Here, the bushing 2 is made of an insulator such as an epoxy resin and is integrally molded together with an internal conductor 6 described later. The outer diameter of the cylindrical portion 23 of the bushing 2 is substantially the same as or slightly smaller than the diameter of the opening 11 of the device case 1, and the outer diameter of the flange portion 24 is the diameter of the opening 11 of the device case 1. The diameter is larger. Note that a conductive paint is applied to the outer surface of the electric field relaxation portion 22 as indicated by a dotted line in the figure.

  The inner conductor 6 is connected to the large-diameter portion 61 having a horizontally long oval shape protruding from the top portion 21 a of the head portion 21 of the bushing 2 and the rear end side of the large-diameter portion 61 via the neck portion 62. A small diameter portion 63 concentrically embedded with the bushing 2 is provided at the distal end portion of the head portion 21, and a circular conductor insertion hole extends from the lower end portion of the small diameter portion 63 to the large diameter portion 61 in the small diameter portion 63. 64 is provided. The inner conductor 6 is formed of a metal rod suitable for energization such as copper or copper alloy, or aluminum or aluminum alloy.

  Here, the neck portion 62 is present at a position corresponding to the top portion 21a of the bushing 2, the outer diameter of the neck portion 62 is smaller than the outer diameter of the small diameter portion 63, and the outer diameter of the large diameter portion 61 is the small diameter portion. The outer diameter of 63 is larger.

  The conductor insertion hole 64 is provided at a position corresponding to the large-diameter portion 61 and is a circular conductor insertion hole (hereinafter referred to as “first conductor insertion hole”) into which a current-carrying portion 7a of the cable conductor connection end portion 7 described later can be inserted. 64a and a circular conductor insertion hole (hereinafter referred to as a “second conductor insertion hole”) 64b provided at a position corresponding to the neck 62 and the small diameter portion 63 and into which the cable conductor connection end portion 7b of the cable conductor connection end 7 can be inserted. These first and second conductor insertion holes 64 a and 64 b are provided so as to be concentric with the receiving port 25 and communicate with the receiving port 25.

  Here, the diameter of the second conductor insertion hole 64b is slightly larger than the diameter of the first conductor insertion hole 64a, and two annular ball storage grooves are formed on the inner peripheral wall of the second conductor insertion hole 64b. 641 and 642 are spaced apart in the longitudinal direction.

  The cable terminal 3 includes a cable insulator 31 and a cable conductor 32 that are exposed by stepping off a terminal of a CV cable. A spindle-shaped outer periphery of the cable insulator 31 spans an outer semiconductive layer 33. A stress cone 4 is attached. Here, the stress cone 4 includes an insulating portion 41 having a rubber-like elasticity such as ethylene propylene rubber (EP rubber) and a semiconductive portion 42, and the outer periphery of the insulating portion 41 corresponds to the inner peripheral wall of the receiving port 25. A tapered portion is provided.

  A bottomed cylindrical inner plug 71 is compression-connected to the tip of the cable conductor 32, and a bottomed cylindrical outer plug 72 is attached to the outer periphery of the inner plug 71 so as to surround the inner plug 71. . An annular concave groove for mounting a tape-like conductor connector, which will be described later, is provided on the outer periphery of the inner end of each of the inner plug 71 and the outer plug 72, and an annular ball is provided on the rear end side of the outer plug 72. A perforation hole is provided at a position corresponding to the storage grooves 641 and 642, and a metal ball b1 for locking the outer plug 72 to the inner wall of the second conductor insertion hole 64b is provided in the perforation hole. Each b2 is mounted so as to be able to appear and disappear in the radial direction. A cylindrical pressing fitting 74 is movably disposed in the axial direction between the outer periphery on the rear end portion side of the inner plug 71 and the outer periphery on the rear end portion side of the outer plug 72. A coiled spring c is disposed between the stepped walls provided on the inner periphery of the intermediate portion of the outer plug 72.

  In the cable conductor connection end 7 having such a configuration, the inner plug 71 is electrically connected to the outer plug 72 by the first conductor connector disposed on the outer periphery of the inner plug 71 on the distal end side, The plug 72 is electrically connected to the large diameter portion 61 of the inner conductor 6 by the second conductor connector disposed on the outer periphery of the outer plug 72 on the distal end side. Here, the inner plug 71, the outer plug 72, and the first and second conductor connectors constitute the energizing portion 7a in the present invention. Further, as will be described later, the locking mechanism between the cable conductor connecting end 7 and the inner conductor 6 due to the movement of the first ball b1 with respect to the first ball housing groove 641 constitutes the first drawing means in the present invention, Similarly, the locking mechanism between the cable conductor connecting end 7 and the inner conductor 6 by the movement of the second ball b2 with respect to the second ball housing groove 642 constitutes the second drawing means in the present invention. The first and second conductors are electrically conductive tapes that expand and contract in the radial direction by being mounted along the circumferential direction in annular grooves provided in the inner plug and the outer plug, respectively. Lamb band).

  The pressing device 5 is disposed on the outer periphery of the pressing metal body 51 having an annular pressing metal body 51 having a trumpet-shaped opening that comes into contact with the tapered outer peripheral surface of the semiconductive portion 42 of the stress cone 4. An annular outer pressing metal 52 is provided, and a spring insertion hole 53 is equally distributed on the lower end side of the pressing metal main body 51 along the circumferential direction. Each of the spring insertion holes 53 has a coiled spring. 54 is attached. The outer pressing metal fitting 52 includes a cylindrical member 52a and an annular pressing member 52b projecting radially inward from the rear end side of the cylindrical member 52a. The pressing metal main body 51, the outer pressing metal 52, and the spring 54 having such a configuration are assembled together in advance.

  In the figure, reference numeral 23a designates a cylindrical shielding fitting embedded concentrically with the cylindrical portion 23 on the rear end side of the cylindrical portion 23, 34 a cable shielding layer, 35 a cable sheath, and A a rear of the shielding fitting. An annular adapter screwed to the outer periphery on the end side, H denotes an annular protective metal fitting attached to the lower surface side of the outer pressing metal 52, and R1, R2, and R3 denote O-rings, respectively.

  Next, a method for assembling the in-gas terminal connection portion of the present invention configured as described above will be described.

  First, the head portion 21 of the bushing 2 is positioned in the device case 1, and the cylindrical portion 23 is disposed so as to protrude from the outer wall of the device case 1 through the opening 11 of the device case 1. The two flange portions 24 are brought into contact with the inner wall of the device case 1 and are hermetically attached by the first bolt B1.

  Next, the cable terminal 3 is inserted into the bushing 2, and the cable conductor connection end 7 having the current-carrying portion 7 a and the drawing portion 7 b is plug-in connected to the conductor insertion hole 64 of the internal conductor 6. The press fitting main body 51 fitted on the 3 side is brought into contact with the semiconductive portion 42 of the stress cone 4, and the second bolt B2 is inserted into the bolt through hole provided in the cylindrical member 52a, and the tip end portion thereof is inserted. Screw into the screw hole of the adapter A. Then, when the second bolt B2 is rotated, the pushing member 52b enters toward the bushing 2 due to the screwing of the second bolt, and as a result, the springs 54 are pressed, and the springs 54 are pressed in the axial direction. Power is granted. As a result, the tapered outer peripheral portion of the insulating portion 41 of the stress cone 4 is pressed against the inner wall surface of the receiving port 25, and as a result, the insulating performance of the interface between the inner wall surface of the receiving port 25 and the outer peripheral surface of the insulating portion 41 is ensured. Is done.

  Thus, when the stress cone 4 is pressed against the inner wall surface of the receiving port 25, the pressing metal piece 74 is pushed upward through the annular stopper 73 disposed at the tip of the stress cone 4, and the pressing metal piece 74 is moved together therewith. The balls b1 and b2 supported on the inclined surfaces of the projecting members 75 and 76 provided on the outer peripheral side in the longitudinal direction are pushed up to the top of the projecting member 75 by the inclined surfaces, respectively, and some of them are balls. Projecting into the storage grooves 641, 642 and the movement of the balls b 1, b 2 in the radial direction are prevented by the projecting member 75. As a result, the inner conductor 6 and the outer plug 72 are locked, and the closure portion 77 of the outer plug 72 is disposed on the closure portion 77 of the inner plug 71 and the closure portion 77 of the outer plug 72. Since the inner plug 71 is fixed to the cable conductor 32, the CV cable is prevented from falling off.

  Next, the cable protection fitting H made of an aluminum alloy metal fitting or the like that has been inserted in advance on the cable terminal 3 side is returned to a predetermined position, and the flange Ha formed on the end face of the cable protection fitting H is pushed by the pressing member of the outer pressing fitting 52. 52b is attached to the end face, and both are fastened by the third bolt B3.

  In addition, in the figure, the code | symbol S shows the winding layer of the waterproofing tape wound between the CV cable and the cable protection metal fitting H, and E has each shown the grounding wire.

As described above, according to the cable termination connecting portion of the present invention, since the energizing portion 7a exists at a position higher than the top portion 21a of the bushing 2, the outer conductor 6 outside the position corresponding to the energizing portion 7a. By increasing the diameter, that is, by increasing the outer diameter of the large-diameter portion 61, a desired energization capacity can be ensured in the plug-in connection portion, and as a result, there is no possibility of reducing the insulation characteristics of the bushing 2. A termination connection can be provided. Further, by increasing the diameter of the inner conductor 6 protruding from the top portion 21a of the bushing 2, that is, by forming the large diameter portion 61 in an oblong shape when viewed from the side, the bushing (epoxy insulating resin) 2 and the device case 1 are formed. Since the electric field does not wrap around the triple junction (triple junction) P where the inner gas insulation and the inner conductor 6 are in contact, there is no possibility of partial discharge occurring at the triple junction P. Further, when the cable conductor connection end portion 7 uses the retaining portion 7b having the first and second retaining means, the cable conductor can be connected even when the cable terminal attached to the bushing 2 is large. It can be securely gripped.

  In the above-described embodiments, the present invention is described with specific embodiments shown in the drawings. However, the present invention is not limited to these embodiments, and as long as the effects of the present invention are exhibited, You may comprise as follows.

  1stly, in the above-mentioned Example, although the case where it applied to the termination | terminus part in gas was described, you may apply to the termination | terminus connection part in oil.

Second, the conductor size of the cable to be attached to the bushing 2 is not limited to the 2000mm ^2, those exceeding 2000mm ^2, or 2000mm may be of less than ^2. Even when a small cable of less than 600 mm ² is used, there is an effect that heat is not generated in the bushing (insulator such as epoxy resin) 2.

  Thirdly, the cable mounted in the bushing 2 is not limited to a rated voltage of 66 to 77 kV, and may be applied to a rated voltage of less than 66 kV or a rated voltage exceeding 77 kV.

  Fourth, the structure of the current-carrying portion 7a at the cable conductor connection end 7 is not limited to the tape-shaped conductor connector (multi-lamb band) type, but the coil spring contact type, tulip contact type, or wedge. Tightening type may be used.

  Fifth, the retaining portion 7b at the cable conductor connecting end portion 7 is not limited to the one where the first and second retaining means are disposed, and may be one where any one retaining means is disposed. Sixth, in the above-described embodiment, the retaining portion 7 b is located in the bushing 2, but it may be located above the top portion 21 a of the bushing 2.

  Seventh, the shape of the balls b1 and b2 in the lock mechanism as the retaining means is not limited to a true spherical shape, and may be, for example, a rectangular parallelepiped shape.

  Eighth, in the above-described embodiment, the cable conductor connecting end portion 7 having the energizing portion 7a and the retaining portion 7b is described. However, in any one of the first to third embodiments of the present invention. May not be provided with the retaining portion 7b.

The longitudinal cross-sectional view which shows an example of the cable termination | terminus connection part of this invention. The partial sectional view of the conventional cable termination connection part. The partial sectional view of the conventional cable termination connection part. The partial sectional view of the conventional cable termination connection part. The partial sectional view of the conventional cable termination connection part.

DESCRIPTION OF SYMBOLS 1 ... Equipment case 11 ... Opening part 2 ... Bushing 22 ... Receiving port 4 ... Cable terminal 6 ... Internal conductor 64 ... Conductor insertion hole 7 ... Cable conductor connection end Part 7a ... Current-carrying part 7b ... Retention part

Claims (3)

A bushing having an inner conductor at the center of the tip and a cable terminal receiving port at the lower end, and a stress cone made of a rubber-like insulating portion and a semiconductive portion inserted into the bushing receiving port. A cable terminal for a large-sized cable having a conductor size of 600 mm ² or more in which a cable conductor connecting end having a current-carrying portion is plug-in connected to a conductor insertion hole provided in a lower end portion of the internal conductor. At the connection,
The inner conductor includes a large-diameter portion protruding from the top of the bushing, and a small-diameter contiguously embedded in the front end portion of the bushing concentrically with the bushing through a neck portion on the rear end side of the large-diameter portion. With
The neck portion is present at a position corresponding to the top of the bushing, the outer diameter of the neck portion is smaller than the outer diameter of the small diameter portion, and the outer diameter of the large diameter portion is larger than the outer diameter of the small diameter portion. The diameter,
In the inner conductor, a circular conductor insertion hole is provided from the lower end portion of the small diameter portion to the large diameter portion,
The cable terminal connection part, wherein the energization part is arranged at a position corresponding to the large diameter part of the inner conductor. Wherein the cable conductor connection end, the cable sealing end according to claim 1, wherein the anchor portion is provided on the lower side of the conducting portion. The retaining portion includes first retaining means and second retaining means, and the conductor insertion hole includes a storage groove at a position corresponding to the first and second retaining means. The cable terminal connecting portion according to claim 1 or 2 , wherein the first and second drawing means are spaced apart along the longitudinal direction of the conductor insertion hole.

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