JPS6176005A - Method of connecting cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a branch connection between a shielded main power cable for intermediate voltage and one less (at least one) other shielded power cable. The invention relates to the termination of intermediate voltage power cables having two or more closely spaced shields.

BACKGROUND OF THE INVENTION 1 "Intermediate voltage" means a voltage ranging from about IKV to about 36 KV.

A branch where at least one main power cable is connected to at least one other cable
``5-1+I Bo1ge'', CI, In some parts and areas, this branch is a power line subdivided from the main distribution line, supplying power for example to retail or various industrial uses.Such a connection This connection is often a “Y” connection when the
It is called a connection or a two-way connection, and this connection is called a two-way connection.
When including two branch cables, this connection is referred to as an "H" connection or three-way connection.

For convenience, the words "Yll" and "H" are used herein to describe such connections. (In some cases, the main cable need not be disconnected and the connectors in the outer circumferential (2-brown) Sometimes it is desirable to terminate intermediate voltage cables with two or more closely spaced shields. ” and “H” connections and methods for forming terminal connections.

[Prior Art 1 A shielded intermediate voltage power cable typically includes at least one conductor, a conductive shield surrounding the conductor, and an insulating layer surrounding the conductive shield. Alternatively, it includes a dielectric layer, a conductive shield around the dielectric layer, a conductive metal shield, and optionally a protective sheath. When connected to a power cable for intermediate voltage with shielding or termination or other such power cable, the dielectric layer is removed or cut to expose a length of conductor, and a certain length of the dielectric layer is removed or cut away to expose a length of conductor. The shield is removed to expose the length.

The conductors are then connected to other cable conductors or terminal lugs. The connection may be made by any convenient method such as compression crimp or soldering. In most cases, this connection is made using a deformable ring.

One method of sealing, shielding, splicing and terminating cables is described in US Pat. No. 4,353,131.

In forming "Y" or "H" connections or termination connections involving adjacent cables, each of the cables is typically independently insulated or shielded. In this way, insulation and shielding is accomplished for three separate cables in the "YI!" connection and four separate cables in the 'H" connection. Individual insulation and shielding processes are bulky and require significant clearance around the assembled parts.

Furthermore, some techniques, such as wrapping insulation tape, require considerable skill. Installation of this connector is difficult in places where space is limited, for example in underground ditches.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a method for forming and sealing "Y" or "H" connections or terminal connections of closely spaced cables that provides a compact construction.

[Configuration and Effects of the Invention 1 According to one aspect of the present invention, a method for forming a branch connection between an intermediate voltage power cable having a shield and at least two other intermediate voltage power cables having a shield is provided. each of said cables has at least one conductor, a dielectric layer around said conductor, in turn a conductive shield on the outside thereof, and said connection. is accomplished by the following method. That is, a portion of the dielectric layer is removed to expose a certain length of conductor, and t
A portion of the shield is removed to expose a length of the z74 body layer, and this formation method connects the cable conductors and the two cables are placed relatively close to each other in a virtually parallel relationship. An electric field relaxation material having an open impedance of about 5 x 10" to 8 x 109 Ωcm is provided around the parallel conductor opening, and
providing an insulation material over the connection extending across the connection and overlapping each shield of the cable, and providing a semiconducting shielding layer over the insulation, the semiconducting shielding layer is electrically connected to the shield of each of the above cables.

Another aspect of the invention includes a branch connection between intermediate voltage power cables having at least three shields, each of said cables having at least #J1 conductor, and having a constant length of conductor. surrounded by a dielectric layer partially removed to expose a conductive shield and a conductive shield partially removed to expose a length of the dielectric layer, and at this location the Two conductor portions of the cable that are relatively close to each other and in a substantially parallel relationship are connected together.

and, at this connection location, an electric field softening material is located between the cables and surrounds each end of the conductive shield of the cables and extends along the exposed dielectric layer and is insulated. the material extends across the connection to overlap the shield of each cable, and a semiconducting shield layer is disposed over the insulation material, and
electrically connected to each of the cable shields.

Further, another aspect of the present invention includes a method for closing the terminal connections of medium voltage power cables having proximate shielding, each of the cables having at least one conductor; It has a dielectric layer around the conductor and, in turn, a conductive shield on the outside of this. Then, each terminal connection is made by the following method. That is, a portion of the dielectric layer is removed to expose a length of the conductor, a portion of the shield is removed to expose a length of the dielectric layer, and is securely attached to each terminal lug; In this sealing method, the cables are located relatively close to each other in a virtually parallel relationship, and an electric field relaxation material having an impedance of approximately 5 x 107 to 8 x 109 ohm-cm is provided between and around the conductors that are parallel to each other. An insulating material is provided on the terminal part so as to overlap the shield part of
A semiconducting shield layer is provided on the insulating material, and the rolled layer is electrically connected to the shield of each cable.

High field areas of adjacent cables at connections or terminations no longer need to be separately insulated and shielded;
It has been found that an ordinary shield can be used to achieve a satisfactory seal.

According to the invention, the connection can be made by an in-line (IN-LrNE) connection method between two main cables, similar to that described in U.S. Pat. No. 4,353,131. In effect, two cables are converted into a single equivalent cable.

The present invention can provide a method for forming and closing "Y" or "H" end connections of closely spaced cables resulting in a compact configuration. Furthermore, the method of the present invention is easily accomplished in the limited spaces encountered in various fields.

Preferably the impedance of the electric field softening material is approximately 3X1
It is between 06 and 5XIO' Ω·Cl1l.

Open voltage cables with shields used for splicing and splicing are prepared in the usual manner. That is, the sheath is cut away to expose a length of the lower layer shield, if any. Seal-
1 It is electrically conductive, but typically includes an external metal layer and a semiconducting layer in close proximity to the dielectric. This metal layer may include lead coating, spirally wound metal tape, shield wire, or the like. The semiconducting layer is generally
It includes a layer of polymeric material with conductive particles, such as carbon black, dispersed therein to provide a grounded smooth skin over the cable insulation layer. When preparing to connect cables,
The gold R layer of the shield is typically cut or removed to expose a length of the dielectric layer.

The semiconducting layer is removed to expose a dielectric layer surrounding the conductor, and the dielectric layer is removed to expose a length of the conductor.

The actual individual cable configuration may differ slightly from the general description above. The compositional changes depend on the degree of general description.

These configurational variations are dependent on the rated voltage being handled, the insulation grade of the material used in the cable, the configuration of the metal or semiconducting shield, and the like. For example, paper-insulated lead-clad cable (PILC) typically has no semiconductivity on the oil-impregnated paper, only a lead jacket and a metal shield on the back. This type of cable is equipped with a protective tube to change the paper insulation to polymeric insulation, and the polymeric cable and conductors are connected to form a Y-connection or an H-connection, possibly using any suitable connector. .

Such connectors typically consist of a metal layer that is compressively deformed by an externally applied compressive force, and the application of force causes the metal layer to come into direct contact with the conductors of the cable. do.

Other methods of connecting the cable conductors, such as soldering or welding, can be used if necessary.

As mentioned above, the connection of two cables, eg, a main cable and a branch cable, are placed in relatively close parallel relationship. When an H-connection is formed, each of the branch cables is preferably located parallel to the main cable. Close parallelism means that the cables are approximately 0.1 to 1.5 cm
It means to be located next to each other at an interval of .

The field softening material is provided on the parallel cables so that it overlaps the end of the semiconducting layer from which the insulating layer has been removed and extends along the adjacent insulating layer. The field softener applied and the configuration supplied will depend to some extent on the voltage of the electrical system. Generally, the field softener used is a polymeric material containing suitable fillers. Approximately 5X10” when measured at ~80 Hertz
It should have an impedance in the range of Ω·cm to approximately 8×10 Ω·cm.

If this connector is approximately 10KV or less, for example 5KV
Or for an 8 K V electrical system, the electric r! ￥The relaxing material is mastic or the like. The masticant is a malleable filler material and can take the form of a tape, sheet, or the like. Typical mitigants used in this class are epihalohydrins based on constructions such as those shown in U.S. Pat. No. 4,378,463. Such materials have a resistance of approximately 1×109Ω·Qln to approximately 5× when measured at 40-80 Hz.
It has an impedance in the range of 109Ω·can.

In another form of application, the field softening material is used as a tubular article. This tubular article can be used as a dimensionally recoverable article, like a heat shrink tube. This form is approximately IOK\1 or more, for example, 15KV
system. The electric field mitigation material and dimensional recovery article prepared here are described in British Patent No. 1+470,501,
No. 1,470.502, No. 1,470,503, No. 1147o, s 04 and U.S. Patent No. 4,363,84
It is stated in No. 2. Such substances are generally
It includes a polymeric material, such as polyethylene, with carbon black dispersed therein to give the material the desired impedance. The electrosurgical relaxation tube used in this invention has a resistance of 5 x 107 to 5 x 109 ohm'' cm, preferably 3 x 10a to 1 x 1 ohm when measured at 40 to 80 hertz
It should take the form of a material with an impedance in the range of 09Ω·C.

In yet another form of application, the field softening material is used as a porous article. The porous article may include two holes extending therein to allow parallel cables to fit therein. The length of the article is sufficient to ensure that it overlaps the semi-conducting layer of the cable shield and extends into the adjacent portion of the insulating layer. The article is dimensionally recoverable and preferably heat shrinkable.

The holes in this article should thus be provided with a larger size to facilitate installation.

Once in place, deflating the article causes it to recover and come into direct contact with both parallel cables.

All areas between parallel cables should be free of air gaps. This region may be completely filled with an electric field relaxation material.

In embodiments where the field softening material does not completely fill the space between the parallel cables, a void filler may be used to fill the remaining space. The void filler is about 2 to about 6, preferably about 2.5 to about 3.2
It should be an insulating material with a dielectric constant of This void filler can be used in any form. This can be in the form of a malleable filler or an extruded thermoplastic.

In a more preferred embodiment of the invention, the void-filling insulation is in the form of an extrusion of thermoplastic material. This configuration is particularly suitable when used as a sleeve.The heat applied to shrink each layer simultaneously causes the void filler to flow, thus
Fill all spaces effectively. To ensure filling of the voids, the filler preferably has a viscosity of approximately 104 voids.

After the Y or H connections are processed as indicated above, they should be insulated and shielded, and the connector shield is connected to the cable shield to provide continuous shielding. One method of sealing a connector is described in the previously mentioned US Pat. No. 4,383.135. According to this method, the Y-connection or the H-connection is sealed by a protective sleeve comprising an inner insulating layer and an outer conductive layer.

The insulating layer overlies the semiconducting layer of the conductive cable shield. The sleeve is preferably provided as a dimensionally recoverable, particularly heat shrinkable, polymeric tubular article.

The insulating layer and the conductive layer may be used as separate articles or may be a composite article as described in US Pat. No. 4,390,745. The description will be explained using the description as a reference. If it is desired to reduce the electric field, additional field softening material can be provided over the connector.

The outer conductive layer is electrically connected to the semiconductive layer of the cable shield. The metal layer of the cable shield is connected to the metal shield of each cable by a braided wire or similar metal member bridging the connectors.

A protective sheath surrounding the entire connector can be utilized. Preferably, the protective sheath is a polymeric tubular article. The tubular article is also preferably provided as a dimensionally shrinkable, in particular heat shrinkable, tubular article or a circumferentially wrapped sleeve. Conventional molded openings may be used to seal around the ends of the protective sheath surrounding the parallel cables. Such openings are generally molded articles with one port at one end and two ports (or more if desired) at the other end.

There are other branch protection methods, such as those described in U.S. Pat. No. 4,298,415, in which during sleeve recovery,
As a closure, clips are used to guide and support the ends of the heat recovery sleeve.

A heat-shrinkable two-hole tube of insulating material can be used to close parallel cables.

A restorable article is a resilient article that is constructed so that it can undergo a significant change in size and configuration when a certain procedure is performed.

Heat recoverable articles, which recover upon heating, are particularly preferred. This is because they are easy to manufacture and a wide range of means for recovery are available.

Typically these articles recover toward the original shape from which they were previously deformed.

However, the term "resilient" as used herein also includes articles that take on new forms even if they have not been previously transformed.

In their most common form, such articles are described, for example, in U.S. Pat.
No. 242 and No. 3,597,372, the invention includes a heat-shrinkable sleeve of a plastic material exhibiting suitable elasticity or soft memory. For example, U.S. Patent No.
．． No. 027,962, the initial dimensional thermostable form is a temporary form in a continuous process that is expanded into a dimensional thermostable form, e.g. by extrusion or into a tube while hot. Might happen. However, in other applications, a preformed dimensionally thermostable article is transformed in separate steps into a dimensionally thermostable form.

In the fabrication of heat recoverable articles, polymeric materials are used to increase the recovery of preferred dimensions. , cross-linking the polymeric material, and
heating the article to a temperature above the melting point of crystalline materials and above the softening point for amorphous materials, in this case likely polymers;
The article is then deformed and cooled in the deformed state so that the deformed state of the article is maintained.

In other articles, for example, British Patent $1,440.5
As described in No. 24, an elastomeric member, such as an outer tubular member, is held in a stretched state as a second member, such as an inner tubular member;
This portion is weakened by applying heat, and the elastic member is thus deformed.

Dimensionally recoverable articles without the use of heat are disclosed in U.S. Pat.
No. 38,970. Such items are
As a retaining member, the elastomeric member in the stretched state is held in the stretched state until the retaining member is removed by dissolving the retaining member or by mechanically breaking or removing it. Typically, such articles include an elastomeric member that is supported in a stretched state by an external tube section that is adhered thereto.

The invention also provides connections and terminal connections made according to each inventive method.

Example 1 Referring to the drawings, like parts are designated by like numbers in each figure.

Cables 1, 2, 3 and 4 in FIG. 1 are spliced together. Cables 1 and 3 constitute a main power circuit, and cables 2 and 4 are branch cables that lead power from the main circuit to the auxiliary circuit. Cable 1゜2,:14 conductors 5,6.7
and 8 are connected together by connectors 9, respectively. Prior to connecting the conductors, the cable is removed by removing the insulation or dielectric layers 10, 11, 12 and 13 of the cable to expose the conductors, as well as half the cable to expose a length of the dielectric layer. Conductivity/114, 15°16 and 17
are removed and the metal shields 18, 19, 20 and 21 are removed to expose a length of the semi-conducting layer of the shield.
is prepared by removing it. The length of each layer to be cut is determined in part by the actual voltages being handled and the type of cable used.

In FIG. 1, the connected cables are shown as 15KV plastic insulated cables.

Cables 1, 2, 3 and 4 are in parallel relationship due to the special connectors used to connect cables 1, 2, 3 and 4. If the cables are not in a parallel relationship during the connection stage, this arrangement of the cables is necessary to take advantage of the compact assembly obtained by utilizing the present invention. In the three-prong connection (H connection) shown in FIG.
This is controlled by providing electric field relaxation tubes 22, 23, 24 and 25 at locations overlapping the peripheries of the cut ends of 16 and 17. The electric field mitigation article is carbon black or
It consists of a conductive polymer comprising a polymer matrix containing dispersed conductive particles such as silicon carbide. Tube articles 14, 15 in this example.
16 and 17 are used as heat-shrinkable tube articles. This interesting item is from Cal 7 Ornia, Menlo Park.

It is commercially available as SCTM, a registered trademark of Raychem Corporation.

The spaces between and around the cables are filled with void-filling insulation 26. As mentioned above, the filler material can be utilized in any specific form. In a preferred embodiment, the filler material is used as an extruded shape shaped to fit between the parallel cables. This is illustrated in FIG. The extruded shape 50 of the filler material in FIG. 5 has a cross-sectional configuration such that the void-fill insulation material can be easily applied between parallel cables.

The connector further includes a synthetic heat-shrinkable tubing article 8. It is protected by Hairi Nishikine Ebi 97 and Tsukuda 1's road bud order 9R. The conductive layer 28 is connected to the cable 1 by a braided wire 29.
The i-wire 29 is spirally wound on the conductive layer 28 to bridge this connector, and is connected to the metal layers 18 and 19 of cables 3 and 4. 20 and 21. A protective sheath 30 is provided over the entire connector and connects the cables 1, 2.3 and 4.
are in contact with the respective protective armor.

Prior to being equipped with a protective sheath, the parallel cables are provided with two-hole tubes or openings 31 and 32. Exterior 30
and openings 31 and 32 are both used in heat-shrinkable articles.

FIG. 2 is a longitudinal cross-sectional view of a lid connection (Y-connection) protected according to a second aspect of the invention. In FIG. 2, cables 1, 2 and 3 are connected together.

Each of the cables has a 5KV extruded dielectric
It's a cable. The cables 1 and 3 constitute a main electric circuit, and the branch cable 2 associated therewith constitutes an auxiliary circuit. The cables are prepared as described above. The water conduction, dielectric layer, semiconducting layer shields and metal shields of cables 1, 2 and 3 are numbered as in FIG. cable 1
．． 2 and 3 are connected by a connector 40. cable 1
and 2 are in close parallel arrangement. Field mitigating material 41 is provided around or between the cuts or edges of semiconducting shields 14 , 15 and 16 and around connector 40 .

It is noted that the field softening material 41 surrounds the ends of the semiconducting layers 14 and 15 of the parallel cables and fills the openings at these ends. The electric field softening material used is shrimp halohydrin, which is based on a component containing trihydrate as a filler. This component has an impedance of 3×109 Ω・am, is a malleable solid at room temperature, and is
It has a viscosity of approximately 105 voids at °C. The remaining space around the connection part, including the space between cables 1 and 2, is filled with void-filling Mi green material 42. Insulating layer 27
and conductive layer 28 are provided across the connector and in contact with the metal shield of each of the cables, as shown in FIG. The braided wires 25 are helically wound onto the conductive layer 28 and each connected to the metal shield of the cable. The connector is then sealed with a protective sheath 30, and the opening 31 is used for the peripheral seal between cables 1 and 2.

FIG. 3 shows a three-prong connection (H) according to another aspect of the invention.
FIG. In Figure 3, cables 1, 2.
3 and 4 are connected together using a connector 9 as shown in FIG.

The electric field relaxation material has two fillings 43 and 44 of this electric field relaxation material.
semiconducting shields 14, 15 . for each of the cables.
It is provided across the ends of 16 and 17. As illustrated in the cross-sectional view of FIG. 4, each plug-type filling 43 and 44 has two holes 46.4 in which the cables are located.
7 is provided. The filler used in this example is heat shrinkable. After the conductors of the cable have been connected by the connector 9, the field-relaxing fillings 43, 44 are placed in the desired locations. Upon heating, the filling shrinks and comes into direct contact with the cables extending through the filling. The filling extends between the parallel cables at the ends of the conductive layer and completely fills the opening and surrounds the ends of the semiconducting layer.

During assembly, a void-free intermediate surface is formed between the filling and the cable extending through the filling.

The periphery of the connector block and the end of the electric field relaxation block are filled with a void-filling insulating material 45 as in the previous embodiment.

The insulation and conductive layers, the braided wire and the outer insulation sheath are provided as described in the previous embodiment.

The invention has been described in terms of preferred embodiments.

It will be readily apparent to those skilled in the art that other modifications are possible within the scope of this invention. For example, each pair of parallel cables in an H-connection can be protected according to different embodiments of the invention.

The present invention utilizes a heat-recoverable member, for example, a dimensionally-recoverable member that does not require extrusion or heating.

In the case of a Y-connection, the diameter of only one cable is enlarged by adding insulation around this single cable to more closely approximate the dimensions of the connector and the combined parallel cables. You can also do that. If necessary, this insulation material is applied as heat shrink tubing.

The invention can also be used in polyphase systems, for example three-phase systems using three-core cables. In this case, the in-phase three or four conductors of the main and branch cables are formed according to the invention.

The connectors for each of the three phases can be shielded independently and a protective sheath can be installed over the entire connector.

As mentioned above, the method of the invention can also be used for terminating two closely spaced cables. In this case, the field mitigation system is the same as when used for parallel cables with two-way or three-way connections. !
,hZ,-! J, /fa%Z, I'ff1na+-
: A common shield can be applied to parallel cables with FrJm. A protective sheath or opening can be used to seal around the terminal.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional view of a three-prong connection, Fig. 2 is a longitudinal cross-sectional view of a two-prong connection, Fig. 3 is a longitudinal cross-sectional view of another embodiment of the three-prong connection, and Fig. 4 is an implementation of Fig. 3. FIG. 5 shows a cross-sectional view of an article of porous field softening material used in the example; FIG. 5 shows a cross-sectional view of an article formed of insulating material located between parallel cables to fill the air gap between the cables. 1.2, 3.4...Cable, 516171 Death. 4 pieces, 9.40...connector, 10, 11.12゜1
3... dielectric layer, 14. f5, 16.17...Semiconducting layer, 18,19,20.21...Metal shield, 2
2.23, 24.25... Electric field relaxation tube, 26.
42.45... Void filling insulating material, 27... Insulating layer,
28... Conductive layer, 2... Braided wire, 30... Exterior, 31.32... Opening, 41... Electric field relaxation material, 4
3゜44...Electric field, relaxation filler.

Claims (9)

[Claims] (1) A method of configuring a branch connection between a shielded intermediate voltage power cable and at least two other shielded intermediate voltage power cables, each of the cables having at least one conductor. a dielectric layer around the conductor, a conductive shield outside the conductor, a dielectric layer around the conductor, and a dielectric layer around the conductor;
A conductive shield is provided on the outside, and the above connection is made by the following method. That is, removing a portion of the dielectric layer to expose a certain length of the conductor, removing a portion of the shield to expose a certain length of the dielectric layer, and removing a portion of the dielectric layer to expose a certain length of the dielectric layer. and this forming method connects the cable conductors, and the two cables are located relatively close to each other in a virtually parallel relationship, and the formation method connects the cable conductors, with the two cables located relatively close to each other in a virtually parallel relationship, and between the parallel conductors and the Around 5 x 10^7 to 8 x 10^9 Ω・c
m and filling the connection with an insulating material extending across the connection and overlapping each shield of the cable; A method for branching and connecting cables, characterized in that a semiconductive shield layer is provided on the cable, and the semiconductive shield layer is electrically connected to each shield of the cable. (2) The method according to claim 1, wherein the electric field relaxation material completely fills the space between the cables. (3) A method according to any one of claims 1 to 2, wherein the electric field moderating material is utilized in the form of a malleable filler component. (4) The method according to any one of claims 1 to 3, wherein the electric field relaxation material is used in the form of a tape. (5) The field moderating material is used in each cable in the form of a dimensionally recoverable tubular article positioned over the cable shield and extending over the dielectric in close proximity to it, with the void filler Claim 1 arranged to fill any remaining space between the parallel cables.
The method described in section. (6) The method according to claim 5, wherein the dimensionally recoverable tubular article is recovered by applying heat thereto. (7) The method according to any one of claims 5 to 6, wherein the void filler is used in an extruded shape. (8) A method for sealing the terminal connections of intermediate voltage power cables with closely spaced shields, each cable having at least one conductor, and a dielectric layer surrounding the conductor. and, in turn, an electrically conductive shield on the outside. Then, each terminal connection is made by the following method. That is, a portion of the dielectric layer is removed to expose a length of the conductor, a portion of the shield is removed to expose a length of the dielectric layer, and is securely attached to each terminal lug; This method of closure allows the cables to be located relatively close to each other in a virtually parallel relationship, with approximately 5 x 10^7 to 8 x 10^9 ohms between and around the parallel conductors.
・Provide an electric field relaxation material having an impedance of between cm, provide an insulating material on the terminal part so as to overlap each shield part of the cable, provide a semiconducting shield layer on this insulating material, and provide the above-mentioned shield layer. is a method of sealing terminal connections, which is characterized in that the cables are electrically connected to the shield of each cable. (9) A branch connection between intermediate voltage power cables having at least three shields, each of said cables having at least one conductor, with a section to expose a length of the conductor. is surrounded by a dielectric layer that has been removed and a conductive shield that has been partially removed to expose a length of the dielectric layer, and at this location relatively close to each other. Two conductor portions of the cable that are in a virtually parallel relationship are connected together. and, at this connection location, an electric field softening material is located between the cables and surrounds each end of the conductive shield of the cables and extends along the exposed dielectric layer and is insulated. the material extends across the connection to overlap the shield of each cable, and a semiconducting shield layer is disposed over the insulation material, and
A cable branch connection characterized in that it is electrically connected to each of the cable shields.