JPH04200218A - Recessed electrodes in prefabricated connections - 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 embedded electrodes for prefabricated connections of plastic power cables.

[Prior Art] A conventional prefabricated connection part will be explained with reference to the drawings. Figure 3 is a sectional view showing an example of the configuration of a prefabricated connection part.
This figure shows the assembled state of the connection part. That is, the ends of the left and right connecting cables 1゜1' are subjected to step stripping, and the cable conductors are exposed and abutted, and the conductor connecting pipe 2 is placed on top of these.
Cover, compress and connect. An epoxy unit 4 having an embedded electrode 3 inside is placed over the outer periphery of this connection part, and a conical pre-molded stress cone 5 that engages with the left and right conical tapered surfaces of this epoxy unit 4 is fitted from the left and right sides. The interface between the cable 1.1' and the epoxy unit 4 is brought into close contact with each other to provide insulation. The embedded electrode 3 is connected to the conductor connecting tube 2 and contributes to alleviating the electric field at the tip of the pre-molded stress cone 5.

[Problems to be Solved by the Invention] By the way, as shown in FIG. 4, which is an enlarged cross-sectional view of FIG. Each conductor is connected by a tube 2, and as a result, the epoxy unit 4 becomes large, the shield electrode 3 embedded therein also becomes large, and a large amount of epoxy resin is required. And about 1 at the time of manufacturing the epoxy unit 4
Due to the difference in thermal expansion coefficient between the epoxy resin and the metal that is the material of the embedded shield electrode, large strains occur in the epoxy resin near the embedded shield electrode 3 due to temperature changes from 50°C to room temperature, resulting in cracks or cracks. Layer peeling occurs on the surface of the buried shield electrode 3, which has the drawback of significantly reducing electrical insulation performance.

The present invention has been made in view of these points, and it is an object of the present invention to provide a novel prefabricated connection part for a plastic power cable that can eliminate the above-mentioned drawbacks and improve quality.

[Means for Solving the Problems 1] According to the present invention, a shield embedded electrode in a prefabricated cable connecting epoxy unit has a structure in which a fixing part and a shield electrode part are combined, and the material of the fixing part is aluminum or stainless steel.

The hard metal is made of copper or copper alloy, and the material of the shield electrode is aluminum or stainless steel.

It is made of porous conductive material such as sintered metal made of non-magnetic metal such as copper or copper alloy, or conductive material such as carbon fiber or carbon powder molded with epoxy resin, and is insulated after the connection is assembled. This is an embedded electrode of a prefabricated connection part that is characterized by being made to allow gas to permeate therein.

Embedded electrodes are made of a porous conductive material such as sintered metal made of non-magnetic metal that can permeate insulating gas, or a conductive material such as carbon fiber or carbon powder molded with epoxy resin. , when impregnating with insulating gas after assembling the connection part,
The insulating gas penetrates well, improving the interface between the epoxy unit and the embedded electrode and the insulation properties of the epoxy unit. Furthermore, since the coefficient of thermal expansion of the material of the buried electrode is similar to that of the epoxy resin, it is possible to prevent strain cracking and layer peeling at the buried electrode interface during manufacture of the epoxy unit.

[Example] The present invention will be described in detail below with reference to the drawings. 1st
The figure is a cross-sectional view showing the assembled state of a prefabricated connection part of a plastic cable for power cables, and FIG. be. That is, cables 1, 1'
The ends on the connection side are subjected to step stripping treatment to expose the cable conductors, and the cable conductors are inserted into the conductor connection tube 2 and pressed from the outer periphery to be compressed and connected. An epoxy unit 4 with an embedded shield electrode 6 embedded therein is placed on the outer periphery of this connection part, and the embedded shield electrode 6 and the conductor connection tube 2 are connected by a non-magnetic hard fixing part 7. connected. This buried shield electrode 6 has an inner surface 6a.
is exposed on the conductor connecting tube 2 side.

The material of the embedded shield electrode 6 is a porous conductive material such as sintered metal made of non-magnetic metal such as aluminum, stainless steel, copper or copper alloy, or a conductive material such as carbon fiber or carbon powder made of epoxy. It is made of resin.

Next, the entire connection part assembled in this way is sealed in a tank, and after degassing the inside of the tank, for example, N2 gas, SF,
By filling in an insulating gas such as gas and pressurizing it, the insulating gas permeates from the exposed part of the inner surface 6a of the embedded shield electrode 6 to the outer surface 6b of the embedded shield electrode 6. By penetrating the resin, the electrical insulation performance of the connection area is significantly improved.

The embedded shield electrode 6 is formed by molding a sintered metal or a conductive material (carbon fiber, carbon powder, etc.) so that the insulating gas can penetrate. penetrates better than the inner surface 6a of the embedded shield electrode 6, and even if peeling occurs on the outer surface 6b from the embedded shield electrode 6 during fabrication of the epoxy unit 4, the insulating gas will penetrate into this peeled part. It is expected that the insulation will improve. In addition, the outer surface 6b of the embedded shield electrode 6
Since the electric field is high, the insulating gas is impregnated into the epoxy resin of the epoxy unit 4 from this outer surface 6b, and the insulation performance is greatly improved.

Furthermore, since the coefficient of thermal expansion of the embedded shield electrode 6 is close to that of the epoxy resin of the epoxy unit 4, even in the case of a large electrode, the epoxy resin and the embedded shield electrode at the time of manufacturing the epoxy unit 4 are different. Another advantage is that it can be manufactured without cracking or delamination at the interface.

[Effects of the invention] As explained above, according to the embedded electrode of the prefabricated connection part of the present invention, after the connection part is assembled, it is inserted into a tank to perform vacuum degassing, and then filled with insulating gas. By applying pressure, the insulating gas permeates through the exposed inner surface of the embedded shield electrode and further permeates into the epoxy resin of the epoxy unit, so that the insulation performance of the connection part is significantly improved. In addition, because the coefficient of thermal expansion of the material of the embedded shield electrode is similar to that of epoxy resin, it is possible to form an epoxy unit without cracking or delamination, even in the case of large electrodes, resulting in a connection with good insulation performance. It becomes possible to form a section.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the configuration of a prefabricated connection part, Figure 2 is an enlarged cross-sectional view of the embedded electrode part in Figure 1, and Figure 3 is a cross-sectional view showing the configuration of a conventional prefabricated connection part. FIG. 4 is an enlarged sectional view of the buried electrode portion of FIG. 3. 1.1'...Cable 2...Conductor connection tube 3.6...Embedded shield electrode 4...Epoxy unit 5...Pre-molded stress cone 7...Fixing bracket Fig. 1 Fig. 2 Figure 3 Figure 4

Claims (1)

[Claims] The shield embedded electrode in the prefabricated cable connection epoxy unit has a combination of a fixing part and a shield electrode part, and the material of the fixing part is aluminum,
Hard metal such as stainless steel, copper or copper alloy is used, and the material of the shield electrode part is aluminum, stainless steel,
It is made of porous conductive material such as sintered metal made of non-magnetic metal such as copper or copper alloy, or conductive material such as carbon fiber or carbon powder molded with epoxy resin, and is insulated after the connection is assembled. An embedded electrode in a prefabricated connection part characterized by allowing gas to penetrate.