JP2000152456A - Connection method for cv cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a CV cable connection method which provides excellent assembling workability, to make a joint compact as well and to stabilize its electrical performance in addition, and moreover to form this kind of joints superior in heat resistance property too by forming a reinforcing insulator in an insulating joint for CV cables without heating the work. SOLUTION: Separation setting is performed by closely sticking and fixing semiconductive layer units 2 in the shape of a conical pipe to the external semiconducting layers of both CV cables 1 respectively on the sides of shrunk diameter ends, separating and facing them opposite to the extended diameter end sides of the layer units 2 to each other, and a metal mold 5 is set from outside these layer units 2 with a diaphragm in between, and the insides of the layer units 2 and the separation set part are filled with liquid-state room temperature setting silicon rubber. After that, the silicon rubber filled in them is set at room temperature, and a reinforcing insulator and a separating part are united into a body to constitute a joint. It is desirable that a two-component type whose setting time is short be used as the room temperature setting silicon rubber. In addition, it is desirable that bridged polyethelene insulator parts be surface-processed with a primer beforehand, to enhance the adhesive property of an interface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming an intermediate connecting portion for a CV cable, and more particularly to a method for connecting a CV cable which does not require a heating operation even in a molding method.

[0002]

2. Description of the Related Art A straight connection portion for a CV cable includes a normal connection portion (NJB) and an insulated connection portion (IJB). The normal connection is a type that simply connects the cables, the insulated connection insulates between the metal sheaths on both sides of the cable,
The purpose is to reduce the sheath potential rise and sheath loss.

For a CV cable of 66 kV to 77 kV class, an ethylene / propylene rubber (EPR) insulating tape winding connection (TJ) is applied, and for a 154 kV CV cable connection, a chemically cross-linked polyethylene tape winding molding method (TMJ) Has been developed and applied to actual railways. An extrusion molding method (EMJ) or a prefabricated method (PMJ or PJ) composed of a pre-mold insulator and an epoxy unit has been developed as a connecting portion for a CV cable of 275 kV to 500 kV.

[0004]

Each connection in the prior art described above has been developed to realize the purpose corresponding to each voltage class. However, each of the connections has the following advantages and disadvantages in terms of manufacturing and structure. Have.

[0005] TJ: Compact and relatively short working time, but not so high in human factors (abnormal tension, etc.) and heat resistance in tape winding work. TMJ: Compact but with heating work. PJ: The working time is short, but the outer diameter is relatively large. EMJ: Compact but long working time (with two heating operations of extrusion and crosslinking).

Therefore, the problems to be solved by the present invention (objects)
Is to form a reinforced insulator at the insulated connection part for CV cable without heating work to make it excellent in assembling workability. Moreover, it is possible to make compact and stable electric performance, and furthermore to make it heat resistant. It is an object of the present invention to provide a method of connecting a CV cable, which can form such a connection portion having excellent performance.

[0007]

The C provided by the present invention
The connection method of the V cable is C
Each of the V cables is pre-inserted with a semiconducting layer unit having a conical tubular shape, and these semiconducting layer units are fixed to the outer semiconducting layer of the CV cable in close contact with the reduced diameter end side. Of the semiconductive layer unit, a die is set via a diaphragm from outside the semiconductive layer unit, and a liquid room temperature-curable silicone rubber is placed in the semiconductive layer unit and in the edge setting section. After the filling, the filled silicon rubber is cured at room temperature to form the reinforcing insulator and the rim portion integrally to form a connecting portion.

The above-mentioned room-temperature-curable (RTV) silicone rubber has excellent heat resistance, stable properties over a wide temperature range, and excellent electrical insulation. In addition, elastic recovery such as compression recovery and tension recovery is good, and gas equivalence is good. There are also flowable and non-flowable types, which are suitable for diversification.

In this case, the RTV silicone rubber is classified into a one-component type and a two-component type as product forms. this house,
The two-component type is a deep curing type in which curing proceeds uniformly on both the surface and the inner surface, and the curing time is shorter than that of the one-component type.

However, while the one-component RTV silicone rubber exhibits good adhesion to most different materials at the time of curing, the two-component RTV silicone rubber often exhibits no adhesion. In this case, if the adherend of the RTV silicone rubber is subjected to a surface treatment with a primer, the adhesiveness can be imparted.

The present invention uses the above RTV silicone rubber as a reinforcing insulator. In this case, the physical properties of the RTV silicone rubber, such as elasticity, tension, and elongation, effectively act as a connection part material.

By applying the two-component type having a shorter curing time as the RTV silicone rubber, the work time for forming the connection portion can be reduced. The curing time is 24 hours at room temperature (20 ° C.), which is promising from the viewpoint of shortening the work.

On the other hand, when looking at the electrical characteristics in the case where RTV silicon rubber is used as the connection portion material, a dielectric breakdown strength of about 20 to 30 kV / mm can be expected, and the CV cable can be provided by providing an appropriate thickness of the reinforcing insulator. It can be sufficiently applied as a connection part.

[0014] RT is used as a reinforcing insulator for the connecting portion for the CV cable.
When V silicone rubber is applied, there is an interface between crosslinked polyethylene (XLPE) and RTV silicone rubber on the CV cable side due to its configuration. By improving the adhesiveness of the interface by using a primer at the interface, the electrical properties of the interface can be expected to be equal to or higher than the performance of the interface between XLPE and rubber stress cone in PJ. The use of a primer as described above allows the application of a two-component RTV silicone rubber.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of a method for connecting a CV cable according to the present invention in the order of steps. First,
In (a), the uncontracted semiconductive layer units 2 and 2 are inserted in advance into each of the CV cables 1 to which the conductors are connected.
One end of each of the semiconductive layer units 2 and 2 is chamfered with a large thickness, so that the edge cut setting described later serves to suppress an increase in electric field, and the other end has a structure capable of thermally contracting. . Therefore, one end of the heating means, for example, a hot air blower 3
By heating in the above, the CV cable is fixedly adhered to the outer semiconductive layer of the CV cable.

(B) shows a state after the semiconductive layer units 2 ', 2' which have been heat-treated as described above are attached. As is clear from this figure, the semiconductive layer unit 2 'has a conical tubular shape, and the reduced-diameter end of the unit 2' is a CV cable 1
The semi-conductive layer unit 2 ′ is tightly fixed on the outer semi-conductive layer, and the chamfered thick portions on the enlarged-diameter end side of the semi-conductive layer unit 2 ′ are opposed to each other, and the edge cut portion is set here.

After the semiconductive layer unit 2 'has been inserted as described above, the RTV silicon rubber is injected as shown in FIG. In this case, due to the configuration of the connection portion of the CV cable, the cross-linked polyethylene insulator stepped off portion of the CV cable which forms the interface with the RTV silicone rubber is surface-treated with a primer. This is preferably performed before the step (A).

In the RTV silicon rubber injection operation, (c)
As shown in the figure, a mold 5 is set from the outside of the semiconductive layer unit 2 ′ via a diaphragm 6, and a resin tank 10 is connected to a resin injection port 8 of the mold 5 via a flexible hose 9. The RTV silicone rubber 11 is stored in a liquid state in the tank 10. A two-component type is used as the RTV silicone rubber.

Then, the inside of the mold 5 is depressurized through the degassing port 6 and the inside of the resin tank 10 is degassed or evacuated from the pressurizing port 12 to remove voids in the RTV silicone rubber 11. After the voids in the RTV silicone rubber 11 have been sufficiently removed, the valves 13 on the resin tank side and the mold side are opened, and pressure is applied from the pressurizing port 12 of the resin tank 10 so that the RTV silicone rubber 11 is removed from the mold. 5, the RTV silicone rubber is filled from the edge setting portions of the semiconductive layer units 2 ', 2' as shown in the figure, and is filled into the semiconductive layer unit through the space between the edge setting portions. Go being.

As described above, the operation of injecting the RTV silicone rubber is continued, and when the RTV silicone rubber is injected to the upper part of the mold 5, the injection operation is completed. The completion of the injection may be confirmed through the observation window 7 provided in the pipe portion of the deaeration port on the upper part of the mold.

When the filling of the RTV silicone rubber is completed as described above, it is left as it is at room temperature to wait for the RTV silicone rubber to harden.

FIG. 2 is a cross-sectional view showing the CV cable connecting portion obtained as described above. As can be seen from this figure, the RT filled and cured as described above.
V silicon rubber is formed as the reinforcing insulator 14. In this case, since the interface between the reinforcing insulator 14 and the crosslinked polyethylene on the CV cable side is treated with a primer, the interface between the RTV silicone rubber (two-component type) and the crosslinked polyethylene has good adhesiveness, and the electrical contact at the interface is good. A characteristic having a certain level or more was obtained, and it was confirmed that it was sufficiently practicable as a connection part for a CV cable.

According to this embodiment, since the formation of the reinforcing insulator does not involve a heating operation, the connecting portion assembling operation can be simplified as compared with the conventional heat treatment method. Since the reinforcing insulator of the connection part is formed by hardening this, it can be perfectly matched to the surface shape of the cable insulator and the inner and outer semiconductive layers, and the structure that can suppress the generation of the minute gap at the interface by itself And the electric performance can be stabilized. In addition, by using RTV silicone rubber having excellent electrical and physical characteristics, it is possible to stabilize electrical performance in addition to providing compactness, and to form this kind of connection portion having excellent heat resistance. it can.

[0024]

According to the present invention as described above, C
The reinforcing insulator in the insulated connecting part for V cable is formed without the heating work, and the assembling workability is excellent.
In addition, the intended problem (objective) of providing a method of connecting a CV cable that can be made compact, stabilize the electrical performance, and form this kind of connection part excellent in heat resistance can be formed. Can be achieved.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a method for connecting a CV cable according to the present invention in each step, (a) is an explanatory view showing a heat shrinking operation of a semiconductive layer unit, and (b) is a semiconductive layer unit after a heat treatment. (C) is an explanatory view showing a state in which a mold is installed and RTV silicone rubber is injected.

FIG. 2 is an explanatory longitudinal sectional view of a CV cable connecting portion obtained by the method of FIG. 1 and using RTV silicone rubber as a reinforcing insulator.

[Explanation of symbols]

 Reference Signs List 1 CV cable 2 Semi-conductive layer unit (not shrunk) 2 'Semi-conductive layer unit (after heat shrinkage) 3 Hot air blower 4 Diaphragm 5 Mold 6 Deaeration port 7 Observation window 8 Inlet 9 Flexible hose 10 Resin tank 11 RTV silicon Rubber (liquid) 12 Pressure port 13 Valve 14 RTV silicone rubber after curing; Reinforced insulator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5G355 AA03 BA02 BA04 BA12 BA14 CA19 CA22 5G375 AA02 BA26 BB48 CB10 DB11 DB32 DB44

Claims (3)

[Claims] 1. A semi-conductive layer unit having a conical tubular shape is previously inserted into each of two CV cables to which conductors are connected, and these semi-conductive layer units are tightly fixed to the outer semi-conductive layer of the CV cable at the reduced diameter end side. Then, the semi-conductive layer units are separated from each other on the enlarged end side so as to face each other, and the trimming is set. A mold is set from the outside of these semi-conductive layer units via a diaphragm, and the liquid room-temperature-curable silicon is set. A method of connecting a CV cable, comprising: filling a rubber inside a semiconductive layer unit and an edge setting portion, and then curing the filled silicone rubber at room temperature to integrally form a reinforcing insulator and an edge portion to form a connection portion. 2. The method of connecting a CV cable according to claim 1, wherein a two-component room temperature-curable silicone rubber is used. 3. The CV cable connection method according to claim 1, wherein the crosslinked polyethylene insulator portions of both CV cables via the conductor connection portion are surface-treated with a primer.