JPH0355803A - Manufacture of arrester - Google Patents

Abstract

PURPOSE:To obtain an arrester for power distribution satisfying various characteristics such as rigidity at low cost by manufacturing an element unit by unifying ZnO elements laminated in a required number and electrode terminals at both ends through diffused junction and molding a heat-shrinkable polymer insulator or an EP rubber molded insulator onto the outer circumferential surface of the unit as a skin. CONSTITUTION:An element unit is manufactured by unifying ZnO elements 1 laminated in a required number and electrode terminals 2, 3 at both ends through diffused junction, and a heat-shrinkable polymer insulator or an EP rubber molded insulator 4 are molded onto the outer circumferential surface of the element unit as a skin. Metallic foils are held among the ZnO elements 1 and the elements 1 and the electrode terminals 2, 3, these elements, terminals and foils are housed in a vacuum furnace, the inside of the furnace is evacuated, and the metallic foils are heated up to a temperature higher than the 80% or more of the melting point of the metallic foild used at least. When the inside of the furnace reaches a fixed temperature, the temperature is held for at least thirty min or more, a reducing gas such as N2 is blown into the vacuum furnace, and these elements, terminals and foils are cooled, thus acquiring a ZnO element unit in which the elements and the electrode terminals at both ends are unified through diffused junction in a contacting section S.

Description

[Detailed Description of the Invention] A. INDUSTRIAL APPLICATION FIELD The present invention relates to a method of manufacturing a lightning arrester used to protect a power system, particularly a power distribution system.

B. Summary of the Invention The present invention is a method for manufacturing a lightning arrester in which an insulator as an outer cover is molded from plastic, rubber, polymer, etc., in which a required number of ZnO elements are stacked together and electrode terminals at both ends are integrated by diffusion bonding. By forming a jacket on the outer circumferential surface of this element unit, the element unit has the rigidity of the lightning arrester, and by eliminating the need for FRP, we are trying to reduce man-hours and costs. be.

C. BACKGROUND OF THE INVENTION In recent years, composite insulators made of FRP (glass fiber reinforced plastic) and an organic sheath have come to be used for power surge arresters, especially surge arresters for protecting power distribution systems. This type of lightning arrester is (1) small and lightweight; (2) It has the advantage that fragments of the container do not fly away when the pressure is released, and especially for those installed on utility poles in urban areas, item (2) above is very effective in preventing accidents resulting in injury or death.

The lightning arrester using the above-mentioned composite insulator has a required number of ZnO (zinc oxide) elements 2I stacked as shown in FIG. The other electrode terminals 24 are placed in a pressurized state, and the resin-impregnated glass fiber 2 shown in FIG.
5 is wound to form the unit shown in FIG. 2C, and then a heat-shrinkable polymer insulator (or EP rubber molded insulator) 26 is molded around it as shown in FIG. As shown in A, ZnO element 2l
The laminate, the disc spring 22, one electrode terminal 23, and the other electrode terminal 24 are housed in the FRP cylinder 25' shown in FIG. 3B, and fixed by screws, adhesives, etc., and then as shown in FIG. 3C. It is manufactured by molding a heat-shrinkable polymer insulator (or EP rubber molded insulator) 26 as shown. As mentioned above, the electrode terminal 23 uses the resin-impregnated glass fiber (FRP material) 25 and the FRP cylinder 25'.
This is because it is difficult to provide rigidity to the element group including 24.

D. Problems to be Solved by the Invention However, in the former case, FR is added to the stack of ZnO elements 21, etc.
Wrap resin-impregnated glass fiber 25, which is the material of P,
Since a curing process is required, the number of steps increases, resulting in high costs. In addition, since the ZnO element 2l and FRP are bonded with resin, thermal stress is generated due to the difference in linear expansion coefficient between the two and changes in ambient temperature, resulting in serious problems such as peeling at the interface or mechanical destruction of the ZnO element. may occur.

On the other hand, in the latter case, it is necessary to firmly fix the element unit Ichiro and the FRP cylinder 25', which increases the number of steps and increases the cost. In addition, since there is a gap between the FRP cylinder 25' and the ZnO element 2l, it is possible that the element will shift due to vibration, and the metallicon that is the element electrode will wear out and its powder will fall inside the FRP cylinder 25'. Unfavorable for maintaining strength.

An object of the present invention is to provide a method of manufacturing a lightning arrester that can produce a lightning arrester for power distribution that satisfies various characteristics such as rigidity at a low cost.

E. Means for Solving the Problems The present invention integrates a required number of ZnO elements stacked together and electrode terminals at both ends by diffusion bonding to form an element unit, and a heat-shrinkable polymer insulator is attached to the outer peripheral surface of this element unit as an outer cover. Alternatively, it is characterized by molding an EP rubber mold insulator.

F. Function Metal foil is sandwiched between the ZnO elements and between the ZnO element and the electrode terminal, and when these are heated in a vacuum furnace, the metal foil is melted. After melting and cooling after a certain period of time, the ZnO elements and the electrode terminals are integrated by diffusion bonding. This is used as an element unit, and it has the rigidity of a lightning arrester.

Next, a heat-shrinkable polymer insulator or the like is molded as a jacket on the outer circumferential surface of the element unit, thereby completing the manufacture of a lightning arrester mainly used for protecting power distribution systems.

G. EXAMPLES Hereinafter, the present invention will be explained in detail based on examples shown in the drawings.

1A and 1B show an embodiment of the present invention. First, as shown in FIG. 1A, a required number of ZnO elements 1 and electrode terminals 2 and 3 at both ends are integrated, and then A heat-shrinkable polymer insulator (or an EP rubber mold insulator or an epoxy resin mold insulator) 4 is molded into the outer cover of the insulator shown in B). ZnO element! The electrode terminals 2 and 3 are integrated using the diffusion bonding method (Japanese Patent Application No. 63-27-4.0).
(Refer to Publication No. 02).

That is, metal foil is sandwiched between the ZnO cords and between the element 1 and the electrode terminals 2 and 3, and these are housed in a vacuum furnace. At this time, pressure may be applied to the element using a weight or the like. After housing, the furnace is evacuated (to 1 x 10 -3 Torr or less) and the inside of the furnace is heated. Heating shall be performed to a temperature that is at least 80% or more of the melting point of the metal foil used. However, the temperature is set so as not to exceed the upper limit of the firing temperature of the ZnO element.

Once the inside of the vacuum furnace reaches a certain temperature by heating in the vacuum furnace, maintain that temperature for at least 30 minutes. This is to make the bonding strength uniform when the metal foil is melted and the ZnO elements are bonded.

Thereafter, by blowing a reducing gas such as N gas into the vacuum furnace and cooling, a ZnO element unit in which the elements and the electrode terminals at both ends are integrated by diffusion bonding at the contact portion S is obtained.

Note that the cooling may be natural cooling.

Next, a heat-shrinkable polymer insulator (insulator!) 4 is molded on the outer peripheral surface of the ZnO element unit. As the heat-shrinkable polymer insulator, for example, HVTM manufactured by Raychem Co., Ltd. is used. A sealing material is applied to the inner surface of the insulator, and the sealing between the element and the electrode terminal is performed by this sealing material.

The surge arrester manufactured in this way has its rigidity reduced to ZnO.
This is carried out by the element unit, and the outer cover is directly formed on the outer peripheral surface of the element unit.・H. Effects of the Invention The present invention described above has the following effects.

(1) The elements and the elements and electrode terminals are integrated by diffusion bonding to form an element unit, and this element unit has rigidity, so there is no need to use FRP, and its winding is easy. It is possible to reduce costs and man-hours, such as by eliminating the need for the process of assembling.

(2) Since the element unit has an integrated structure, it is easy to carry and handle, and it is expected that the number of assembly steps will be reduced and the manufacturing process will be automated.

(3) The number of parts can be reduced and parts management becomes easier.

(4) Since the outer sheath is formed directly on the element unit with an integrated structure, problems such as peeling of the element and FRP due to temperature changes and falling of metallic contact powder due to vibration can be resolved, greatly contributing to improving the reliability of the surge arrester. It is possible.

(5) There is almost no need to adjust the manufacturing equipment when the number of elements increases or decreases due to changes in the rated voltage.

[Brief explanation of drawings]

Figure lA. B is a manufacturing process explanatory diagram showing an example of the method for manufacturing a lightning arrester according to the present invention, FIGS. 2A-D and 3A-
C is a manufacturing process explanatory diagram showing a conventional example. 1... ZnO element, 2 and 3... electrode terminal, 4...
・Heat-shrinkable polymer insulator. 2 other people Figure 1 A B Figure 3 A B C

Claims (1)

[Claims] (1) The required number of ZnO elements stacked together and the electrode terminals at both ends are integrated by diffusion bonding to form an element unit,
A method for manufacturing a lightning arrester, which comprises molding a heat-shrinkable polymer insulator or an EP rubber molded insulator as an outer covering on the outer peripheral surface of the element unit.