JPH0970131A - Power cable connecting part and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the electrical deterioration and the decline of withstand voltage by a method wherein the boundaries between electrodes and an epoxy resin insulator are eliminated and gaps which are electrically harmful are eliminated. SOLUTION: An epoxy unit 1 of which a part of a prefabricated joint(PJ) is composed of electrodes 5 and an epoxy resin insulator 3. Liquid 7 whose electrical resistivity is not larger than 10<5> Ω.cm and whose dynamic viscosity is not larger than 10000cSt is provided in gaps between the electrodes 5 and the epoxy resin insulator 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power cable connecting part and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, tape type joints (TJ), tape type mold joints (TMJ), extrusion mold joints (EMJ) and prefabricated joints (PT) have been known as methods for connecting power cables. Among them, the prefabricated joint (PJ) is shown in FIG.
As shown in, left and right cables 31L, 31R
The ends of the cable are stripped off, and the cable conductors are exposed and brought into contact with each other to connect the cable conductors to each other.

An epoxy unit 37 made of an epoxy resin insulator 35 having an electrode 33 embedded inside is covered on the outer periphery of this connecting portion, and a conical rubber is engaged with the left and right conical tapered surfaces of the epoxy unit 37. The mold stress cones 39L and 39R are fitted from the left and right, and the interfaces of the cables 31L and 31R and the epoxy unit 37 are brought into close contact with each other for insulation.

As described above, the prefabricated joint (PJ) is roughly divided into the cables 31L and 31R, the epoxy unit 37, and the rubber mold stress cones 39L and 39.
It consists of three parts, R. Among them, the epoxy unit 37 is the epoxy resin insulator 3 having the electrode 33.
5, the electrode 33 is made of a metal such as aluminum (Al) or copper (Cu), and the epoxy resin insulator 35 is made of an epoxy cured material containing an inorganic filler.

As shown in FIG. 6, the epoxy unit 37 uses a mold 41 composed of a bottom plate 41D and a plurality of side plates 41S, and a core 43 in which the electrode 33 is previously mounted in the mold 41. The side plate 4 of the mold 41
The epoxy resin 45 is injected between the 1S and the core 43, the epoxy resin 45 is cured, and then the epoxy resin 45 is removed from the mold 41.

[0006]

By the way, the conventional epoxy unit 37 described above has an epoxy resin insulator 35 in which a metal electrode 33 made of copper, aluminum, iron and alloys thereof and an epoxy resin 45 are hardened. Since there is a heterogeneous interface, the metal electrode 33
Due to the difference in coefficient of thermal expansion between the epoxy resin insulator 35 and the epoxy resin insulator 35, there is a drawback that they do not adhere to each other and a void is formed at the interface, resulting in electrical deterioration of the cable component and reduction of withstand voltage.

The conventional epoxy unit 3 described above is also used.
In the manufacturing method of No. 7, the core 43 with the metal electrode 33 attached is set in the mold 41, and then the epoxy resin 45 is added.
Since it was injected, it was not possible to confirm whether or not the interface between the electrode 33 and the epoxy resin 45 was adhered to each unit.

An object of the present invention is to provide a power cable connecting part and an electric cable connecting part which have no interface with an epoxy resin insulator and are free from electrically harmful voids to prevent electrical deterioration and withstand voltage reduction. It is to provide the manufacturing method.

[0009]

In order to achieve the above object, a power cable connecting part of the present invention according to claim 1 is
The epoxy unit part which constitutes a part of the prefabricated joint is composed of an electrode and an epoxy resin insulator, and an electric resistance of 10 ⁵ Ω.
It is characterized by containing a liquid having a kinematic viscosity of 10000 cst or less and a cm or less.

According to a second aspect of the present invention, there is provided a method for manufacturing a power cable connecting part in which an electric resistance 10 is obtained from an injection hole formed in a mold with the mold embedded in an epoxy resin insulator.
A liquid having a kinematic viscosity of ⁵ Ω · cm or less and a kinematic viscosity of 10,000 cst or less is injected, and then pressure is applied so that the liquid is contained between the epoxy resin insulator and the mold.

In the above-mentioned structures of claims 1 and 2, since a liquid having an electric resistance of 10 ⁵ Ω · cm or less and a kinematic viscosity of 10000 cst or less is contained between the epoxy resin insulator and the electrode, a gap is formed. Is eliminated and electrical deterioration and withstand voltage reduction are prevented. Further, the electrode shape follows the thermal expansion and contraction of the material due to the thermal action such as heat cycle.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an explanatory view showing an example of the form of an embodiment of the epoxy unit 1 according to the present invention. This epoxy unit 1 has the same shape as a conventional epoxy unit, and is made of an epoxy resin insulator (cured product) 3 obtained by curing an epoxy resin. A metal electrode 5 is embedded in the epoxy resin insulator 3. An electric resistance of 10 ⁵ Ω is provided between the epoxy resin insulator 3 and the electrode 5.
The liquid 7 having a kinematic viscosity of 10,000 cst or less is contained.

The liquid 7 is made of, for example, liquid epoxy resin containing mercury or carbon. Moreover, the electric resistance is 10 ⁵ Ω · cm or less and the kinematic viscosity is 10,000 cs.
It has characteristics of t or less.

As described above, the liquid 7 is contained between the epoxy insulator 3 and the electrode 5 so that no gap is generated between the epoxy resin insulator 3 and the electrode 5. Therefore, it is possible to prevent electrical deterioration and prevent a decrease in withstand voltage.

As a method of manufacturing the epoxy unit 1, as shown in FIG. 2, a metal mold 11A of a metal electrode portion is jointed in a mold 9 composed of a bottom plate 9D and a plurality of side plates 9S. The core 13 is set, the electrode part mold 11B is set on the bottom plate 9D, the electrode part mold 11c is set on the upper part, and the side plate 9S of the mold 9 and the core 1 are set.
Epoxy resin 15 is injected between 3 and 3, and the epoxy resin 15 is hardened when a certain time has elapsed. Next, by removing the mold 9 and the core 13, the epoxy resin insulator 3 (epoxy resin cured product) as the epoxy unit 1 is obtained as shown in FIG.

After the electrode 5 is embedded in the epoxy resin insulator 3 as the epoxy unit 1 as shown in FIG. 3, the liquid epoxy containing mercury or carbon is injected through the injection hole 17 formed in the electrode 5. By injecting a liquid such as resin 7 and then applying pressure, the resin insulator 3
The liquid 7 is contained between the electrode 5 and the electrode 5. Gas is vented from the hole 19 formed in the electrode 5.

In this way, by containing the liquid 7 between the epoxy resin insulation 3 and the electrode 5, the above-mentioned effect is exhibited.

[Embodiment] For example, as shown in FIG. 4A, metal electrodes 23 and 25 are vertically opposed to a cubic epoxy resin insulator 21 of 100 mm, and as shown in FIG. As shown in FIG. 2B), the electrodes 23, 25 have opposite voids (200 μm) 23A, 2
5A was made to contain a liquid epoxy resin containing mercury or carbon (resistivity 10 ⁵ Ω · cm). As a comparative example, the AC withstand voltage (KV / mm) was measured when nothing was provided in the void (200 μm) and when the electrodes 23 and 25 were opposed to each other without providing the void. I got the result.

[0020]

[Table 1] As can be seen from the results shown in Table 1, the withstand voltage (KV / mm) of Examples 1 to 5 is 135 to 150, while
50 to 80, in which nothing is provided in the voids of Comparative Examples 1 to 3,
The usual manufacturing method was 100-150.

Therefore, by inserting the liquid 7 such as mercury or carbon-containing epoxy resin between the epoxy resin insulator 3 and the electrode 5 of this embodiment, an AC withstand voltage equivalent to that of the usual manufacturing method was obtained. Therefore, since the liquid 7 is contained in the gap between the epoxy resin insulator 3 and the electrode 5, there is no void, so that electrical deterioration can be eliminated and reduction in withstand voltage can be prevented. The electrode 5 having no void is formed for a component having a complicated electrode shape. Moreover, the electrode type can follow the thermal expansion and contraction of the material due to the thermal action such as heat cycle.

The present invention is not limited to the above-described embodiment, but can be embodied in other forms by making appropriate changes.

[0023]

As can be understood from the examples of the embodiments described above, according to the inventions of claims 1 and 2, the electrical resistance between the epoxy resin insulator and the electrode is 10 ⁵ Ω · cm or less. In addition, since a liquid having a kinematic viscosity of 10,000 cst or less is contained, voids can be eliminated, and electrical deterioration and withstand voltage reduction can be prevented. Further, the electrode shape can be made to follow the thermal expansion and contraction of the material due to the thermal action such as heat cycle.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an epoxy unit of the present invention.

FIG. 2 is an explanatory view illustrating a manufacturing method of the present invention.

FIG. 3 is an explanatory view illustrating a manufacturing method of the present invention.

FIG. 4 is an explanatory diagram for experimentally measuring AC withstand voltage of the epoxy unit of the present invention.

FIG. 5 is an explanatory view showing a conventional prefabricated joint.

FIG. 6 is an explanatory diagram illustrating a method for manufacturing an epoxy unit that constitutes a part of a conventional prefabricated joint.

[Explanation of Codes] 1 Epoxy unit 3 Epoxy resin insulator (cured epoxy product) 5 Electrode 7 Electric resistance 10 ⁵ Ω · cm or less, kinematic viscosity 10000
Liquid below cst

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroaki Okuyama 42-1, Shintomicho, Futtsu City, Chiba Prefecture Fujikura Futtsu Factory

Claims (2)

[Claims] 1. An epoxy unit part constituting a part of a prefabricated joint is composed of an electrode and an epoxy resin insulator, and an electric resistance of 10 ⁵ Ω · cm or less is provided between the electrode and the epoxy resin insulator. And kinematic viscosity 10,000 cst
A power cable connecting part characterized by containing the following liquid. 2. An electric resistance of 10 ⁵ Ω from an injection hole formed in a mold with the mold embedded in an epoxy resin insulator.
A method for producing a power connecting part, which comprises injecting a liquid having a kinematic viscosity of 10000 cst or less and then applying pressure so that the liquid is contained between the epoxy resin insulator and the mold.