JP2001045624A - Method of terminating semiconductor layer of electric cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of partial discharge, at terminal connection time or middle connection of an electric cable, having a semiconductor layer. SOLUTION: The figure shows the vicinity of the terminal of a cable semiconductor layer 5, in the enlarged sectional view of one part of the terminal connection of a power cable 2. A conductive or semiconductive ring 20, consisting of soft material, is fitted around the exposed insulator 4 of a power cable 2 (figure a), and a connector is slid onto the power cable 2, together with a semiconductor layer 13 on an apparatus side (figure b). A void 19 at the terminal of the cable semiconductor layer 5 is filled with a flexible conductive or semiconductive ring 20, and partial discharge phenomena, which were occurring due to the existence of this void 19, can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a terminal of a semiconductive layer of an electric cable, which is suitable for application to a terminal connection or an intermediate connection of a power cable.

[0002]

2. Description of the Related Art For example, when a connection device is attached to a power cable at a connection portion such as a terminal connection portion or an intermediate connection portion of the power cable, a method of simply inserting the connection device into the power cable is employed. FIG. 2 shows an example of an object to which the present invention is applied, and is a partial cross-sectional view of a terminal connecting portion 1 of a power cable, which is common to the present invention and the conventional example. In the figure, reference numeral 2 denotes a power cable. The power cable 2 is made of an EP rubber (ethylene propylene rubber) or the like mixed with an insulator 4 such as cross-linked polyethylene, carbon, and the like in this order from the inside to the outer periphery of a central conductor 3. A semiconductive layer (cable semiconductive layer) 5 and a shielding layer 6 are covered, and a sheath 7 of, for example, PVC or the like is further covered. In addition, the illustrated terminal connection unit 1
Reference numeral 11 denotes a conductor connecting rod, 12 is a conductor lead rod, 12 is an insulator made of EP rubber or the like, 13 is a semiconductive layer made of EP rubber or the like mixed with carbon or the like, 14 is a bracket, and 15 is an insulator. A push fitting, 16 is a cable holding fitting, and 17 is an epoxy pipe. Note that a portion other than the power cable 2 and the cable holding bracket 16 in the above-described terminal connection portion 1 is referred to as a connection device 18.

FIG. 3 shows a conventional method for treating a semiconductive layer terminal, and is an enlarged view of a portion corresponding to a portion A in FIG. On the inner surface of the semiconductive layer (device-side semiconductive layer) 13 on the connection device 18 side, a recess 13a is formed corresponding to the terminal portion of the semiconductive layer (cable semiconductive layer) 5 on the power cable 2 side. When the connecting device 18 is inserted into the power cable 2 together with the device-side semiconductive layer 13, the device-side semiconductive layer 13 is inserted into the recess 13a so that the device-side semiconductive layer 13 is insulated from the insulator 4 and the cable semiconductive layer. It contacts the outer peripheral surface of the layer 5.

[0004]

As described above, when a connection device such as a terminal connection portion is attached to the power cable 2, a method of simply inserting the connection device 18 into the power cable 2 is employed. Due to the rubber elasticity of the semiconductive layers 5 and 13, there is a problem that voids (gaps) 19 are likely to be generated at the terminal end surfaces of the device-side semiconductive layer 13 and the cable semiconductive layer 5 as shown in the figure. . When such a void 19 exists, partial discharge may occur, which may cause breakage of the power cable 2 and the connection device 18. Conventionally, when the connecting device 18 is inserted, the surface of the insulator 4 of the power cable 2 is coated with silicone oil to improve the dielectric strength, but this is not always effective. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional disadvantages, and an object of the present invention is to provide a method for treating a semiconductive layer terminal that does not generate a partial discharge at the time of terminal connection or intermediate connection of an electric cable having a semiconductive layer. And

[0005]

According to the present invention, there is provided an electric cable provided with a semiconductive layer on the outer periphery of an insulator on the outer periphery of a conductor. A semiconductive layer terminal treatment method for attaching a connection device having a conductive layer, comprising a flexible material at a position of a terminal end surface of the semiconductive layer on the electric cable side on an exposed outer periphery of the insulator. The connection device is attached to the electric cable by fitting a conductive or semiconductive ring.

A second aspect of the present invention is to attach a connection device having a semiconductive layer in contact with the exposed insulator and the semiconductive layer to an electric cable having a semiconductive layer on the outer periphery of the insulator around the conductor. A semi-conductive layer terminal treatment method, wherein a conductive or semi-conductive paint is applied to a portion near the end of the semi-conductive layer on the side of the electric cable on the outer periphery of the exposed insulator, to thereby form a connection device. It is characterized by being attached to an electric cable.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The connection part of the electric cable targeted by this embodiment is a terminal connection part shown in FIG.
That is, the terminal connection part 1 is of an epoxy tube type. FIG.
1 is not described again, but FIG.
A terminal of the semiconductive layer (cable semiconductive layer) 5 on the side of the power cable (electric cable) 2 is provided on the inner surface of the semiconductive layer (device-side semiconductive layer) 13 on the connected device 18 side. When the connecting device 18 is inserted into the power cable 2 together with the device-side semiconductive layer 13, the device-side semiconductive layer 13 forms the outer peripheral surface of the insulator 4 and the cable semiconductive layer 5. Contact

In the present invention, before the connecting device 18 is inserted into the power cable 2, as shown in FIG. 1 (b), a conductive or semiconductive ring 20 is placed around the insulator 4 of the power cable 2. Fit it in. In this case, the ring 20 is fitted at a position in contact with the terminal end face of the cable semiconductive layer 5 as shown in the figure. As a material of the ring 20, for example, EP rubber (ethylene propylene rubber) mixed with carbon can be used. Next, when the connecting device 18 is further inserted together with the device-side semiconductive layer 13 as shown by the arrow in FIG. 1B, the recess 13a of the device-side semiconductive layer 13 becomes the cable semiconductive layer as shown in FIG. The void 19 between the cable semi-conductive layer 5 and the terminal end face of the cable semi-conductive layer 5 is almost completely filled with the layer 5 and is filled with the crushed flexible ring 20. Since the ring 20 has conductivity or semi-conductivity, it is possible to eliminate a partial discharge phenomenon occurring in a portion where the void 19 was present.

In place of the ring 20, a conductive or semiconductive paint can be applied to the outer periphery of the insulator 4 of the power cable 2. In this case, the cable semiconductive layer 5
Is applied to the surface of the insulator 4 in the vicinity of the terminal. Then
The connection device 18 is inserted into the power cable 2 together with the device-side semiconductive layer 13. As a result, the surface of the insulator 4 in the void portion of the power cable 2 becomes conductive, and the inner surface of the void becomes the same potential, so that the partial discharge phenomenon in the void can be prevented.

Although the above embodiment is applied to the terminal connection, the present invention can also be applied to the intermediate connection and other connection of the power cable. In addition, the present invention can be applied to an electric cable other than the power cable as long as the electric cable has a semiconductive layer on the outer periphery of the insulator around the conductor.

[0011]

According to the present invention, a conductive or semiconductive ring 20 made of a flexible material is provided on the exposed outer periphery of the insulator 4 of the electric cable 2 at the terminal end surface of the cable semiconductive layer 5. So that the cable semi-conductive layer 5
The void (gap) 19 of the terminal is filled with the conductive or semi-conductive ring 20, and the partial discharge phenomenon caused by the existence of the void 19 can be eliminated. Also, by applying a conductive or semiconductive paint to the outer peripheral surface of the cable insulator 4 in the vicinity of the terminal of the cable semiconductive layer 5, the occurrence of the partial discharge phenomenon can be similarly prevented.

[Brief description of the drawings]

FIG. 1 shows a method for treating a semiconductive layer terminal of an electric cable according to an embodiment of the present invention, wherein (A) corresponds to a part A of a terminal connection part in FIG. It is a figure in the middle stage at the time of inserting in a cable.

FIG. 2 is a partial cross-sectional view showing an example of an object to which the present invention is applied, which is a partial cross-sectional view of an epoxy tube type terminal connection portion, which is common to the present invention and the conventional example.

FIG. 3 is a diagram for explaining a problem of a conventional method for treating a semiconductive layer terminal, and corresponds to a portion A in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Termination connection part 2 Power cable (Electrical cable) 3 Conductor 4 Insulator (Cable insulator) 5 Semiconductive layer (Cable semiconductive layer) 6 Shielding layer 7 Sheath 11 Conductor lead-out rod 12 Insulator (insulator on device side) 13 Semi-conductive layer (device-side semi-conductive layer) 16 Cable holding bracket 18 Connection device 19 Void 20 Conductive or semi-conductive ring

Claims (2)

[Claims] An electric cable (2) provided with a semiconductive layer (5) on the outer periphery of an insulator (4) on the outer periphery of a conductor (3) is exposed to the insulator (4) and the semiconductive layer (5). ), Wherein the connecting device (18) provided with the semiconductive layer (13) that comes into contact with the electrical cable (2) is mounted on the outer periphery of the exposed insulator (4). A conductive or semiconductive ring (21) made of a flexible material is fitted to the position of the terminal end face of the semiconductive layer (5) on the side of ()), and the connection device (18) is attached to the electric cable (2). A method for treating a semiconductive layer of an electric cable. 2. An electric cable (2) provided with a semiconductive layer (5) on the outer periphery of an insulator (4) on the outer periphery of a conductor (3), the insulator (4) and the semiconductive layer (5) being exposed. ), Wherein the connecting device (18) provided with the semiconductive layer (13) that comes into contact with the electrical cable (2) is mounted on the outer periphery of the exposed insulator (4). )) Near the terminal of the semiconductive layer (5),
Applying conductive or semiconductive paint to connect equipment (8)
Is attached to an electric cable (2).