JP2000208307A - Surge arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightning arrester using fewer number of part items. SOLUTION: In a lightning arrester, in which a plurality of zinc oxide elements 4 is laminated in series via metallic plates 14, recessed sections 16B for putting-in the elements 4 are formed on both surfaces of the metallic plates 16 by surrounding the metallic plates 16 with metallic rings 16A having rounded cross sections. In this way, since the recessed sections 16B, in which the nonlinear elements are put, are formed on both surface of the metallic plates 16 and the elements are fit in the recessed sections 16B, the number of part items used in the lighting arrester and accordingly, the manufacturing cost of the arrester can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester having non-linear elements such as zinc oxide elements stacked in series.
In particular, it relates to an arrester having a small number of parts.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view showing the structure of a conventional lightning arrester. Metal fittings 2 and 3 are attached to the upper and lower portions of the insulator 1, and an insulating gas such as nitrogen gas or SF ₆ gas is sealed inside the insulator 1 and a plurality of columnar zinc oxide elements 4 are formed of metal. They are stacked in series via a plate 5. The laminated zinc oxide element 4 is interposed between the upper metal press 6 and the lower metal press 7, and an insulating rod 8 is passed through the metal presses 6, 7, and the end of the insulating rod 8 is The zinc oxide element 4 is clamped by screwing. A metal gap member 11 is interposed between the lower part of the metal holder 7 and the metal fitting 3. On the other hand, a metal gap member 10 is disposed above the metal holder 6, a compressive spring 9 is interposed between the metal gap member 10 and the metal fitting 2, and the laminated zinc oxide element 4 is attached to the metal holder 6. , 7 are fixed inside the insulator 1.

In FIG. 4, a zinc oxide element 4 is a non-linear element, and has a characteristic that its resistance value changes with applied voltage. That is, when an overvoltage is applied to the zinc oxide element 4, the resistance value of the zinc oxide element 4 itself decreases and a discharge current flows inside the zinc oxide element 4. Thereby, the overvoltage applied to the zinc oxide element 4 is suppressed to be low, and the electric devices connected in parallel to the zinc oxide element 4 can be protected from the overvoltage. The number of series stacked zinc elements 4 is determined by the system voltage. As the system voltage increases, the number of series stacked zinc oxide elements 4 increases. The metal retainers 6 and 7 and the insulating rod 8 are for fixing the zinc oxide elements 4 stacked in series, and the spring 9 is for pressing the metal retainer 6 downward through the metal gap member 10. belongs to.

In the structure of the lightning arrester as shown in FIG. 4, there is a case where the metal plate 5 is not interposed between each of the stacked zinc oxide elements 4. It is known that a configuration in which a metal plate is interposed between each of the four has the following three effects.

First, according to Japanese Patent Application Laid-Open No. 8-45708, the adhesion between the zinc oxide elements is achieved by interposing a metal plate with a conductive adhesive on the joint surface between the zinc oxide elements. It is disclosed that the property is improved.

Secondly, according to JP-A-8-279402 and JP-A-9-63809, the heat dissipation of heat generated when a discharge current flows through a zinc oxide element due to the interposition of a metal plate is improved. Is disclosed. That is, if the metal plate is formed of a material having excellent thermal conductivity such as copper, the heat of the zinc oxide element can be radiated to the outer periphery via the metal plate, and the life of the zinc oxide element is prolonged.

Third, according to Japanese Patent Application Laid-Open No. Hei 5-13142, in a pollution-resistant lightning arrester having a configuration in which an insulator is lengthened to increase the surface leakage distance, a laminate of zinc oxide elements is used. In contrast, the insulator becomes very long, so the potential difference between the lower end of the laminate and the insulator increases. However, the laminate of the zinc oxide element extends in the lamination direction due to the interposition of the metal plate. The potential difference between the lower end of the arrester and the insulator is reduced, the electric field stress inside the surge arrester is remarkably reduced, and the deterioration of the insulation is suppressed by the generation of an internal corona.

Although not shown as a conventional example,
The zinc oxide element 4 is SF
It may be stored in a metal tank filled with ₆ gases. In this case, the insulator 1 shown in FIG. 4 is replaced with an insulated cylinder without folds, and the configuration in which the zinc oxide element 4 is sandwiched via the insulating rod 8 is exactly the same as that in FIG.

[0009]

However, the conventional lightning arrester as described above has a problem that the number of parts is large. In other words, since the zinc oxide element is fixed via the insulating rod, many parts such as upper and lower metal retainers, a plurality of insulating rods, and a plurality of screws for screwing the ends of the insulating rod are required. It is used. Therefore, it takes time to assemble the zinc oxide element, and the manufacturing cost is increased. An object of the present invention is to provide an arrester having a small number of components.

[0010]

According to the present invention, there is provided a lightning arrester comprising a plurality of non-linear elements laminated in series via a metal plate. It is preferable that a concave portion to be fitted with the linear element is formed, and the non-linear element be fitted into the concave portion. Thereby, the non-linear elements need only be fixed to the recesses of the metal plate, and many parts such as insulating rods are not required unlike the conventional case.

In this configuration, a metal ring having a round cross section may be provided on the outer periphery of the metal plate.
Thereby, the electric field at the outer peripheral end of the metal plate is reduced, and the heat radiation characteristics of the nonlinear element are improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a sectional view showing a configuration of a lightning arrester according to an embodiment of the present invention. A metal plate 16 is interposed between the columnar zinc oxide elements 4, and the zinc oxide element 4 is fitted into recesses 16 </ b> B formed on both surfaces of the metal plate 16. A metal ring 16 </ b> A having a round cross section is provided on the outer periphery of the metal plate 16.

FIG. 2 is an enlarged sectional view of a main part of FIG. On both surfaces of the metal plate 16, recesses 16B to be fitted with the zinc oxide element 4 are formed. 1 and 2 are the same as the conventional configuration in FIG. 4, and the same parts as those in the conventional art are denoted by the same reference numerals and detailed description thereof will be omitted.

In FIG. 2, the inner diameter of the recess 16B is formed to be equal to or slightly smaller than the outer diameter D of the zinc oxide element 4, so that the recess 16B and the zinc oxide element 4 are fitted. ing. Also, by securing the depth F of the concave portion 16B, the zinc oxide element 4 is formed in the concave portion 16B.
Is fitted.

In FIG. 1, the zinc oxide element 4 is
Since the zinc oxide element 4 is fixed to the metal plate 16 by being fitted into the metal plate 6B, there is no need to use upper and lower metal retainers or insulating bars as in the related art. Since the number of parts is reduced, the time for assembling the zinc oxide element 4 is also reduced, and the manufacturing cost can be reduced. Also, the metal ring 16A
Reduces the electric field around the metal plate 16. Thereby, the withstand voltage of the outer peripheral surface of the zinc oxide element 4 increases, and the reliability of the zinc oxide element 4 improves. In addition, metal ring 1
6A, if a material having excellent thermal conductivity such as copper is used integrally with the metal plate 16, the cooling effect of the zinc oxide element 4 can be reduced.
Of the conventional device. That is, the heat radiation area into the gas is increased as compared with the case of FIG. 4 by the amount of the metal ring 16A protruding from the zinc oxide element 4 to the outer peripheral side, and the cooling efficiency is improved. Thereby, the life of the zinc oxide element 4 is increased.

In FIG. 2, the depth F of the recess 16B may be zero. In this case, if the zinc oxide element 4 is fitted into the recess 16B, the relative position between the zinc oxide element 4 and the metal plate 16 is determined. Thereafter, as shown in FIG. By tightening the entire laminated body composed of the metal plate 16 and the metal plate 16, the zinc oxide element 4 can be fixed.

FIG. 3 is a sectional view showing the structure of a lightning arrester according to another embodiment of the present invention. Metal ring 12A
From the opening of the recess 12B of the metal plate 12 to the ring 1
It is provided via 2C. The rest is the same as the configuration of FIG. When the metal plate 12 is manufactured with a mold, casting can be performed with the same mold by replacing only the core for molding the recess 12B even if the outer diameter of the zinc oxide element 4 changes.

FIG. 5 is a sectional view of a main part showing a configuration of a different conventional lightning arrester, which is disclosed in Japanese Patent Application Laid-Open No. 8-279402. Metal plate 14 between zinc oxide elements 4
And a metal ring 14 </ b> A having a round cross section is provided on the outer periphery of the metal plate 14. The rest of FIG. 5 is the same as the configuration of FIG. This metal plate 14
The shape of the recess 14B is different from the embodiment of FIG. That is, the rounded shape of the metal ring 14A is the same as that of the metal ring 16A of FIG. 2, but the concave portion 14B does not have a fitting structure with the zinc oxide element 4. Therefore, the metal plate 14 alone cannot support the zinc oxide element 4, and the zinc oxide element 4 needs to be fixed with the insulating rod 8 shown in FIG.

FIG. 6 is a sectional view of a principal part showing the structure of a further different conventional lightning arrester, which is disclosed in Japanese Patent Application Laid-Open No. Hei 5-13142. A metal plate 5 is interposed between each of the stacked zinc oxide elements 4. The metal plate 5 interposed for extending the laminate of the zinc oxide element 4 in the laminating direction is formed in the same shape as the zinc oxide element 4. The configuration is different from that of the metal plate 16 of the embodiment of FIG. 2 in which the concave portion 16B to be fitted with the element 4 is formed. The stacked body in which the zinc oxide elements 4 and the metal plates 5 are alternately stacked is separated by a metal partition plate 15 every predetermined number. Depressed portions 15B for receiving the zinc oxide element 4 and the metal plate 5, respectively, are formed on both surfaces of the partition plate 15. Insulating rods 8 for tightening and fixing the stacked body of the zinc oxide elements 4 in the stacking direction extend through the plurality of through holes on the outer peripheral side of the partition plate 15. The rest of FIG.
This is the same as the configuration in FIG.

The partition plate 15 has recesses formed on both sides thereof, similarly to the metal plate 16 of the embodiment shown in FIG. 2, but has a different structure. That is, the concave portion 15B of the partition plate 15 is formed for positioning for positioning the zinc oxide element 4 at the center of the insulator, and is formed by the concave portion 16B of the metal plate 16 in the embodiment of FIG. Unlike the concave portion formed for fixing the zinc oxide element 4 as described above, it is not fitted with the zinc oxide element 4. Further, since the partition plate 15 in FIG. 6 is not for fixing each of the plurality of zinc oxide elements 4, it is not necessary to interpose the same between all the zinc oxide elements 4. 4 is different from the configuration interposed between all the zinc oxide elements 4 such as the metal plate 16 in the embodiment of FIG. ing. The outer peripheral portion 1 of the partition plate 15 shown in FIG.
The cross-sectional shape of 5A is different from the outer peripheral portion of the metal plate 16 in the embodiment of FIG. 2 and is not rounded, so that the electric field at the outer peripheral end is not reduced.

[0021]

As described above, according to the present invention, the number of parts can be reduced by forming a concave portion on both surfaces of a metal plate to be fitted with a non-linear element and fitting the non-linear element into the concave portion. Manufacturing cost can be reduced.

In this configuration, by providing a metal ring having a round cross section on the outer periphery of the metal plate, the reliability of the non-linear element is improved and the life of the non-linear element is prolonged.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a lightning arrester according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of FIG. 1;

FIG. 3 is an enlarged sectional view of a main part showing a structure of a lightning arrester according to another embodiment of the present invention;

FIG. 4 is a sectional view showing a configuration of a conventional lightning arrester.

FIG. 5 is a sectional view of a main part showing a configuration of a different conventional lightning arrester.

FIG. 6 is a sectional view of a main part showing a configuration of a further different lightning arrester according to the related art.

[Explanation of symbols]

4: zinc oxide element, 12, 16: metal plate, 12A, 16
A: metal ring, 12B, 16B: recess

Claims (2)

[Claims] 1. A lightning arrester comprising a plurality of non-linear elements stacked in series via a metal plate, wherein a concave portion is formed on both surfaces of the metal plate so as to be fitted with the non-linear element, and the concave portion is formed in the concave portion. A lightning arrester characterized by fitting a linear element. 2. The lightning arrester according to claim 1, wherein a metal ring having a round cross section is provided on an outer periphery of said metal plate.