JP2014180165A - Power cable connecting method and power cable connecting part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power cable connecting method and a power cable connecting part capable of reducing connection length required for connecting a power cable while securing a drawing resistance and a contact area.SOLUTION: An axial line direction center part 21A that is a predetermined portion on a center side of a sleeve (conductor connection pipe) 21 to the sleeve 21 from both ends of which a conductor 12 is inserted, and axial line direction side parts 21B that are both side portions in an axial line direction of the sleeve 21 to the axial line direction center part 21A are compressed, so that inner peripheries of the respective parts 21A, 21B contact the conductor 12 and a step 24 is formed at a boundary of the inner peripheries of the respective portions 21A, 21B after compression.

Description

  The present invention relates to a power cable connecting method and a power cable connecting portion for connecting a conductor exposed at an end portion of a power cable using a conductor connecting pipe.

  As a method of connecting the conductors of the power cable, a compression connection method using a sleeve which is a conductor connection pipe is mainly used. Conventionally, in order to increase the pull-out resistance of the compressed power cable, the outer shape of the sleeve is formed to have a small diameter at the central portion in the longitudinal direction, and both sides of the small diameter portion are formed into large diameter portions having a larger outer diameter than the small diameter portion. A technique for forming and setting the outer diameter of the small-diameter portion to a size that is not compressed by the die when the large-diameter portion is compressed by a die for conductor connection has been proposed (see, for example, Patent Document 1). .

JP 2007-27058 A

However, in the conventional device, in the portion of the small diameter portion of the sleeve, it is not possible to ensure sufficient contact with the conductor of the power cable, and accordingly, in order to secure a contact area that forms a sufficient electric conduction path Will increase the connection length.
In particular, when an aluminum conductor is used for a power cable, the aluminum conductor is more likely to be oxidized than a copper conductor, and more likely to creep, so the connection length must be made longer.
That is, since the contact resistance is increased by an oxide film formed on the surface of the aluminum conductor by oxidation, the connection length must be made longer.
In addition, the connection resistance can be lowered by strongly pressing the sleeve and the conductor, but if the contact pressure per unit area is too high, the conductor will creep later and the contact pressure will decrease. Contact resistance increases. Aluminum easily creeps (creep occurs even at a low pressure), and the contact pressure per unit area cannot be increased. Therefore, it is necessary to increase the connection length.
For these reasons, the connection length becomes longer when the conventional compression connection method for increasing the pull-out resistance is used for the power cable of the aluminum conductor.
When the connection length becomes long, it is necessary to lengthen other parts such as an insulator and a protective tube attached to the outside of the connection portion (conductor connection portion), leading to an increase in cost of the entire power cable connection portion.

  The present invention has been made in view of the above-described circumstances, and ensures a pull-out resistance and a contact area, and at the same time, a power cable connection method and a power cable connection portion capable of shortening the connection length required to connect the power cable. The purpose is to provide.

  In order to solve the above-described problems, the present invention provides a power cable connection method in which a conductor exposed at an end of a power cable is inserted from both ends of the conductor connection pipe, and the conductor connection pipe is compressed to connect the cables together. In addition, with respect to the conductor connection tube in which the conductor is inserted from both ends, a predetermined portion on the central portion side of the conductor connection tube, and both side portions in the axial direction of the conductor connection tube with respect to the predetermined portion, It compresses so that a level | step difference may be formed in the boundary part of the internal peripheral surface of each site | part after compression, and the internal peripheral surface of this contacts the said conductor.

The said structure WHEREIN: The said both sides site | part of the said conductor connection pipe | tube is compressed rather than the predetermined site | part of the said conductor connection pipe | tube.
Further, in the above configuration, a first compression step for compressing a region including the predetermined portion and the both side portions, and a second compression for further compressing the both side portions, with respect to the conductor connection pipe into which the conductor is inserted from both ends. It is characterized by performing a process.

In the above configuration, in the first compression step, the outer shape of the conductor connection tube is compressed into a square shape, and in the second compression step, the outer shape of the conductor connection tube is compressed into an arc shape. And
Moreover, the said structure WHEREIN: The said predetermined part is an axial direction center part of the said conductor connection pipe | tube, It is characterized by the above-mentioned.
The present invention relates to a method for connecting a power cable in which conductors exposed at the ends of a power cable are connected by compressing the conductor connection pipe, and the step of compressing the conductor connection pipe at a constant compression rate over substantially the entire length; And a step of compressing a portion other than the central portion in the longitudinal direction at a higher compression rate.

Further, according to the present invention, in the connection portion of the power cable in which the conductor exposed at the end of the power cable is inserted from both ends of the conductor connection tube and the conductor connection tube is compressed to connect the cables, the conductor is connected from both ends. The inserted conductor connection tube includes a first compression portion in which a predetermined portion on the central side of the conductor connection tube is compressed and contacts the conductor, and both side portions in the axial direction of the conductor connection tube with respect to the predetermined portion. And a second compression part having a step at a boundary with the inner peripheral surface of the predetermined part.
The present invention relates to a power cable connecting portion in which conductors exposed at the ends of a power cable are connected by compressing the conductor connecting tube, and the central portion of the conductor connecting tube is compressed at a constant compression rate, The other portions are compressed at a higher compression rate and have a step between the central portion and the portions other than the central portion.
In this case, the conductor of the power cable may be an aluminum conductor.

  According to the present invention, it is possible to secure the pull-out resistance and the contact area, and to shorten the connection length required for connecting the power cable.

It is the figure which showed the power cable connection part which concerns on embodiment of this invention. (A) is the figure which showed the connection part of the conductor of the electric power cable just before a 1st compression process, (B) is sectional drawing which looked at FIG. 2 (A) from the surface orthogonal to a cable axis line. (A) is the figure which showed the connection part of the conductor of the electric power cable after a 1st compression process, (B) is sectional drawing which looked at FIG. 3 (A) from the surface orthogonal to a cable axis line. (A) is the figure which showed the connection part of the conductor of the power cable just before a 2nd compression process, (B) is sectional drawing which looked at FIG. 4 (A) from the surface orthogonal to a cable axis line. (A) is the figure which showed the connection part of the conductor of the electric power cable after a 2nd compression process, (B) is sectional drawing which looked at FIG. 5 (A) from the surface orthogonal to a cable axis line. It is a figure where it uses for description of a modification.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a power cable connection unit according to an embodiment of the present invention.
The power cable connecting portion 10 shown in FIG. 1 has a structure in which a pair of power cables 11 are connected via a sleeve (conductor connection pipe) 21. The sleeve 21 is inserted with the conductors 12 of the pair of power cables 11 from both ends, and the sleeves 21 are compressed from the outside in the radial direction so that the conductors 12 are mechanically and electrically connected to each other.
This power cable connection portion 10 is applied to an intermediate connection portion of a power cable for underground transmission line, and around this power cable connection portion 10 is a reinforcing insulating layer, a shielding layer, and a shielding layer that control the electric field distribution in the periphery. Surrounding parts such as a water layer and a protective tube for protecting them are arranged. For this reason, when the power cable connecting portion 10 becomes longer in the axial direction, the surrounding parts become longer.

An aluminum electric wire is used for the power cable 11, and the conductor 12 is composed of a stranded wire in which aluminum or aluminum alloy wires are twisted and bundled. Note that the power cable 11 is not limited to an aluminum electric wire, and an electric wire using copper or a copper alloy can also be applied. The conductor 12 is covered with a coating such as an internal semiconductive layer, an insulating layer, an external semiconductive layer, or a shielding layer.
The end portion of each power cable 11 is subjected to a terminal treatment to peel off the coating and expose the conductor 12, and each exposed conductor 12 is inserted from both ends of the sleeve 21. Note that only the conductor 12 is inserted into the sleeve 21.

The sleeve 21 is a metal cylinder member having conductivity such as copper, and functions as a conductor connection tube that connects the pair of power cables 11. The sleeve 21 is a cylindrical member having a constant inner diameter and outer diameter before compression.
1 shows the sleeve 21 after the compression stroke, the inner diameter and the outer diameter of the sleeve 21 are not constant. Further, as shown in FIG. 1, the inner diameter and the outer diameter are reduced by the compression, so that the shape before the compression of the sleep 21 is a cylindrical shape with a constant inner diameter and outer diameter within the range that can be compressed to the shape of FIG. Not limited to this, other cylindrical shapes may be used.

  As shown in FIG. 1, in this embodiment, the sleeve 21 after the compression stroke includes a first compression portion 22A obtained by compressing the axial center portion 21A of the sleeve 21, and the sleeve 21 with respect to the first compression portion 22A. A second compression portion 22B is formed by compressing the axial direction side portion 21B. Each of the first compression portion 22A and the second compression portion 22B is such that the inner peripheral surface of the sleeve 21 is in contact with the outer peripheral surface of the conductor 12 in each portion 22A, 22B, and the inner portion of the sleeve 21 in each portion 22A, 22B. A step 24 is formed at the boundary portion of the peripheral surface (also corresponding to the boundary portion of the outer peripheral surface of the conductor 12).

In the compression process of the present embodiment, the first compression stroke and the second compression stroke are executed.
FIG. 2A is a diagram illustrating a connection portion of the conductor 12 of the power cable 11 immediately before the first compression stroke, and FIG. 2B is a diagram illustrating the cable axis (the length of the power cable 11) in FIG. It is sectional drawing seen from the surface orthogonal to the direction.
As shown in FIGS. 2A and 2B, in the power cable 11, the conductor 12 has a perfect circular cross section, and the sleeve 21 has a through hole 25 into which the conductor 12 can be inserted.
As shown in FIG. 2 (A), the conductors 12 of the power cable 11 are inserted until they substantially come into contact with each other in the axial center portion 21A of the sleeve 21, and then the sleeve 21 is compressed by a pair of dies 31 and 32. By compressing into a square shape at a rate, each conductor 12 and the sleeve 21 are compressed and connected over the entire length of the sleeve.

  The pair of dies 31 and 32 are rectangular compression dies that are longer in the axial direction than the sleeve 21, and the inner surfaces form compression recesses 31 </ b> A and 32 </ b> A each having a half shape of a regular hexagon. By the pair of dies 31 and 32, the entire sleeve 21 is compressed into a substantially hexagonal outer shape. As the dies 31 and 32, known square compression dies can be applied.

As shown in FIG. 3, the connection portion of the conductors 12, 12 after the first compression stroke has a hexagonal outer shape of the sleeve 21.
As shown in FIGS. 3A and 3B, in the first compression process, the entire sleeve 21 made of metal is compressed into the same cross section, so that the compression rate is constant in the axial direction of the sleeve 21. In this way, in the first compression process, the entire sleeve 21 is compressed and deformed so as to have a diameter smaller than the original diameter, and the entire inner peripheral surface of the sleeve 21 is brought into substantially uniform contact with the outer peripheral surface of the conductor 12. In other words, in the first compression stroke, the entire inner peripheral surface of the sleeve 21 is compressed so as to contact the outer peripheral surface of the conductor 12 substantially evenly.

By this first compression stroke, a first compression portion 22A that is in contact with the conductor 12 is formed in the axial center portion 21A that is away from both ends of the sleeve 21.
Further, in this configuration, as shown in FIG. 3A, both the sleeve 21 and the conductor 12 are made smaller by reducing both the metal sleeve 21 and the conductor 12 of the power cable 11 than the original diameter. Contact widely. In this way, it is possible to easily secure an electric conduction path by ensuring a wide contact area.
In the first compression process, the case where both the sleeve 21 and the conductor 12 are reduced in diameter compared to the original diameter is described, but not limited thereto, the sleeve 21 and the conductor 12 are in close contact with each other. What is necessary is just to compress, and the diameter reduction of the conductor 12 is not essential.

Next, the second compression process performed after the first compression process will be described.
FIG. 4 is a diagram immediately before the second compression stroke.
As shown in FIG. 4 (A), in the second compression stroke, the axial side portion 21B avoiding the axial central portion 21A compressed in the first compression stroke with respect to the sleeve 21 is changed in the first compression stroke. It compresses with the dice | dies 35 and 36 with a compression rate higher than a fixed compression rate. In this case, the high compression rate is defined based on the diameter of the sleeve 21 before being compressed in the first compression stroke. Two sets of dies 35 and 36 are prepared, and one set is arranged on each side of the central portion 21A in the axial direction.

The dies 35, 36 are round compression dies that are shorter in the axial direction than the sleeve 21, and the inner surfaces form semicircular compression recesses 35A, 36A. The dies 35 and 36 further compress the axial side portion 21B compressed in the first compression stroke, and compress the axial side portion 21B into a round outer shape along a substantially circular arc. .
Further, the two sets of dies 35 and 35 and the dies 36 and 36 may be formed integrally or separately. Moreover, you may comprise so that a pair of dice | dies 35 and 36 may be moved and the axial direction side part 21B of both sides may be compressed separately.

FIG. 5 shows the connection portion of the conductor 12 of the power cable 11 after the second compression stroke.
As shown in FIGS. 5 (A) and 5 (B), in the second compression stroke, the axial side portions 21B of the metal sleeve 21 are compressed, so that a part of the inner peripheral surface of the sleeve 21 is further compressed. Reduce diameter by compressive deformation. Due to this diameter reduction, the central portion side of the conductor 12 becomes higher than the both end portions at the boundary portion between the inner peripheral surface of the axial direction side portion 21B and the inner peripheral surface of the axial direction central portion 21A. A step 24 is formed.
In addition, this boundary part can also be called the boundary part of the outer peripheral surface of the conductor 12 corresponding to the axial direction side part 21B and the axial direction center part 21A, and forming the level | step difference 24 in the outer peripheral surface of this conductor 12. It is synonymous.

Thus, the second compression step forms the second compression portion 22B in the axial direction side portion 21B in contact with the conductor 12 and having the step 24 at the boundary with the inner peripheral surface of the axial central portion 21A. The
In this case, due to the step 24, the conductor 12 bites into the sleeve 21 at the axial center portion 21A, and the sleeve 21 bites into the conductor 12 at the axial side portion 21B. In the axial center portion 21A, a step 24 is formed in which the central portion side of the conductor 12 protrudes to the outer peripheral side from both end portions, so that a wedge effect is generated on the tapered surface of the step 24. This wedge effect makes it difficult for the conductor 12 of the power cable 11 to come out of the sleeve 21 and improves the pull-out resistance.
As described above, the power cable connecting portion 10 in which the pair of power cables 11 are connected via the sleeve 21 is configured.

  As described above, according to the power cable connecting portion 10, the step 24 between the first compression portion 22A and the second compression portion 22B is formed as shown in FIG. The pull-out resistance of the power cable 11 can be improved. Further, since the first compression portion 22A and the second compression portion 22B are in contact with the conductor 12, the entire inner peripheral surface of the sleeve 21 can be brought into contact with the conductor 12, ensuring a wide contact area and an electric conduction path. can do.

As described above, in the present embodiment, as shown in FIGS. 1 and 5, the sleeve (conductor connection tube) 21 into which the conductor 12 is inserted from both ends is separated from at least the both ends of the sleeve 21. The axial center portion 21A that is a portion, and the axial side portions 21B that are both side portions in the axial direction of the sleeve 21 with respect to the axial center portion 21A, and the inner peripheral surfaces of the portions 21A and 21B are in contact with the conductor 12 In addition, by compressing so that a step 24 is formed at the boundary between the inner peripheral surfaces of the portions 21A and 21B after compression, the pulling resistance of the power cable 11 is improved, and the sleeve 21 and the conductor 12 A wide contact area was secured.
Since the contact area is thus secured widely, an electric conduction path can be secured, and even if the contact pressure per unit area between the aluminum conductor 12 and the sleeve 21 is lowered, a strong pressure contact state can be achieved as a whole. The connection resistance between them can be lowered.

In addition, it is possible to shorten the connection length of the power cable 11 necessary for securing the pull-out resistance and the contact area, and it is possible to provide a connection method of the power cable 11 and the power cable connection portion 10 that can realize this. become.
In addition, since a special method or structure other than compression is not required, the connection method of the power cable 11 is simple, and the complexity of the structure of the power cable connection unit 10 can be avoided.
Thus, since the connection length of the power cable 11 can be shortened, the sleeve 21 can be shortened, and the peripheral parts of the power cable connection portion 10 can be shortened. Thereby, it is easy to reduce the size of the power cable connecting portion 10 and its peripheral structure.

  Further, in this configuration, the axial side portions 21B that are both side portions of the sleeve 21 are compressed rather than the axial central portion 21A of the sleeve 21, so that the conductor 12A is a sleeve as shown in FIGS. 1 and 5A. The diameter of the power cable 11 is the largest at a position corresponding to the central portion 21 </ b> A in the axial direction of 21. As a result, the pull-out resistance can be improved efficiently.

In this configuration, the first compression step of compressing the region including the axial center portion 21A and the axial side portion 21B and the second compression step of further compressing the axial center portion 21A are performed. It becomes easy to ensure a contact area over the entire length. Moreover, the existing compression die | dye can be applied to the compression die | dye used for each process.
Further, according to the first and second compression strokes, the axial direction side portion 21B is compressed in two times, it is easy to ensure a large amount of compression rather than compressing in one time, and Compression is also easy.

Further, in the first compression step, the outer shape of the sleeve 21 is compressed into a square shape, and in the second compression step, the outer shape of the sleeve 21 is compressed into an arc shape, so that it is easier than the case where the same shape is compressed twice. Can be compressed and deformed.
Furthermore, the compression of the central portion 21A in the axial direction enables the tips of the conductors 12 of the pair of power cables 11 and the sleeve 21 to be brought into contact together, and the tips of the conductors 12 and the sleeve 21 are separately compressed. Is unnecessary. Moreover, about the axial direction side part 21B compressed more largely than the axial direction center part 21A, a compression area becomes narrower than a 1st compression process, and a small compressor can be utilized.

The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied without departing from the gist of the present invention.
For example, contrary to the above-described embodiment, the axial center portion 21A of the sleeve 21 may be compressed rather than the axial side portion 21B of the sleeve 21. Even in this case, a wide contact area between the sleeve 21 and the conductor 12 can be secured.
In the above-described embodiment, the case where the compression process is performed in the first compression process and the second compression process has been described. However, the present invention is not limited to this, and the compression process is performed in one compression process or three or more compression processes. You may do it. The point is that the inner peripheral surface of each part 21A, 21B is in contact with the conductor 12 and the inner peripheral surface of each part 21A, 21B is compressed after the axial center part 21A and the axial side part 21B of the sleeve 21 are compressed. The compression may be arbitrarily performed within a range in which the step 24 is compressed so that the step 24 is formed at the boundary.

Moreover, although the case where the axial direction center part 21A and the axial direction side part 21B of the sleeve 21 are compressed was demonstrated, it does not restrict to this. For example, as illustrated in FIG. 6, the axially central portion 21A is compressed as a region not compressed at the center and the compressed portions 21A1, 21A1 on both sides thereof by the first compression stroke. The axial side portions 21B and 21B may be compressed by the second compression stroke so as to sandwich 21A1 and 21A1. Accordingly, the inner peripheral surfaces of the predetermined portions (parts 21A1, 21A1) separated from at least both ends of the sleeve 21 and the both side portions (axial direction side portions 21B, 21B) in the axial direction of the sleeve 21 with respect to the predetermined portions are formed. A connecting portion in contact with the aluminum conductor 12 can be formed.
Moreover, although the above-mentioned embodiment demonstrated the case where this invention was applied to the power cable connection part 10 which connects the power cable 11 for underground cables, the power cable connection part which connects power cables other than an underground cable The present invention may be applied to.

DESCRIPTION OF SYMBOLS 10 Power cable connection part 11 Power cable 12 Conductor 21 Sleeve (conductor connection pipe)
21A Axis direction center part 21B Axial direction side part 22A 1st compression part 22B 2nd compression part

Claims (9)

In the connection method of the power cable, the conductor exposed at the end of the power cable is inserted from both ends of the conductor connection tube, and the conductor connection tube is compressed to connect the cables.
With respect to the conductor connection tube into which the conductor is inserted from both ends, a predetermined portion on the central side of the conductor connection tube and both side portions in the axial direction of the conductor connection tube with respect to the predetermined portion A method for connecting a power cable, wherein compression is performed such that a step is formed at a boundary portion of the inner peripheral surface of each part after compression, and the inner peripheral surface is in contact with the conductor.   The method for connecting power cables according to claim 1, wherein the both side portions of the conductor connection tube are compressed rather than a predetermined portion of the conductor connection tube.   A first compression stroke for compressing a region including the predetermined portion and the both side portions and a second compression stroke for further compressing the both side portions are performed on the conductor connection pipe in which the conductor is inserted from both ends. The power cable connection method according to claim 2, wherein the power cable is connected to the power cable. In the first compression step, the outer shape of the conductor connection tube is compressed into a square shape,
The power cable connection method according to claim 3, wherein in the second compression step, the outer shape of the conductor connection tube is compressed into an arc shape.   5. The power cable connection method according to claim 1, wherein the predetermined portion is a central portion in an axial direction of the conductor connection pipe.   In the method of connecting a power cable in which conductors exposed at the ends of the power cable are connected by compressing the conductor connection tube, the step of compressing the conductor connection tube over a substantially entire length at a constant compression rate, and the center in the longitudinal direction And a step of compressing a portion other than the portion at a higher compression rate. In the power cable connection part that inserts the conductor exposed at the end of the power cable from both ends of the conductor connection pipe, compresses the conductor connection pipe and connects the cables,
The conductor connecting pipe into which the conductor is inserted from both ends is
A first compression portion in which a predetermined portion on the central side of the conductor connection tube is compressed and contacts the conductor;
A second compression portion having both sides in the axial direction of the conductor connecting pipe compressed with respect to the predetermined portion, contacting the conductor, and having a step at a boundary portion with an inner peripheral surface of the predetermined portion. Power cable connection characterized by.   In the power cable connecting part in which the conductors exposed at the ends of the power cable are connected by compressing the conductor connecting pipe, the central part of the conductor connecting pipe is compressed at a constant compression rate, and the parts other than the central part in the longitudinal direction are compressed. A power cable connecting portion, characterized in that the power cable connecting portion is compressed at a higher compression rate and has a step between the central portion and a portion other than the central portion.   The power cable connecting portion according to claim 7 or 8, wherein the conductor of the power cable is an aluminum conductor.