JPH0520947A - Polymer insulator type lightning arrester - Google Patents

Abstract

PURPOSE:To provide a polymer insulator type lightning arrester excellent in mechanical strength in lightning arrester provided with a pressure relief function for relieving pressure laterally by devising a discharging hole through which gas can be discharged. CONSTITUTION:Ring-like ZnO elements 2 are stacked in the outer periphery of a FRP insulating core member 1. Similar ring-like electrodes 4 each with a gas discharging hole 4' formed on the side wall thereof are disposed in the upper and lower parts of the ZnO elements 2 or interposed between the predetermined ZnO elements 2. They are fixed by metal fittings 3, 3' from above and below, and covered with a sheath 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester using a non-linear resistor, and more particularly to a polymer insulator type lightning arrester applied to power lines and the like.

[0002]

2. Description of the Related Art Since most surge arresters have a sealed structure, if internal elements are destroyed and a short-circuit arc is generated, the internal pressure of the arrester may rise rapidly and the insulator tube may explode. Therefore, a pressure release device is generally provided to prevent this.

In this pressure relief device, pressure relief devices are provided above and below the lightning arrester so that when the internal pressure reaches a predetermined value, the pressure relief film or the like is broken and gas is ejected from the upper and lower ejection holes to the outside. Some of them have a discharge port provided on the side surface of the container of the arrester as shown in FIG.

FIG. 3 is a vertical sectional front view of a conventional polymer insulator type lightning arrester in which a discharge port is provided on the side surface of the container, and 31 is an FRP made of a fiber reinforced plastic (hereinafter abbreviated as FRP) and an insulating cylinder. Outer cylinder member, 32 is this F
A non-linear resistor ZnO element stacked and accommodated inside the RP outer cylinder member 31, 33 is a metallic lid that holds the ZnO element in the FRP outer cylinder member 31 from above and below, and 34 is a side surface of the FRP outer cylinder member 31. A gas discharge hole is formed in a predetermined number at a predetermined number, and a numeral 35 is a weatherproof, insulating member jacket. Assembling is performed by accommodating the ZnO element 32 in the FRP outer cylinder member 31, pressing the ZnO element 32 with the metal lid 33 from above and below via the spring 36, and fixing the upper and lower lids to the FRP outer cylinder member 31. A main body is formed, and the outer cover 5 is attached to the outer surface of the main body by molding or heat shrinkage. In the case of molding, the space between the FRP outer cylinder member and the ZnO element 32 may be simultaneously molded through the gas discharge hole 34.

When gas is generated in the FRP outer cylinder member, the gas G breaks the jacket 35 from the discharge hole 34 and is discharged to the outside of the arrester, as shown by the arrow in the figure.

[0006]

As described above, since the conventional structure is such that the discharge hole is provided in the FRP outer cylinder member, (1) the FRP outer cylinder member is required to have mechanical strength.
Since the discharge hole is provided, when internal pressure load, tensile load, and bending load occur, stress concentration is caused in the vicinity of the discharge hole.
It is necessary to reduce the nominal stress (average stress in the area without stress concentration). As a result, it is necessary to increase the wall thickness of the FRP outer cylinder member, which causes the FRP outer cylinder member, the jacket, and other parts to become large (size, mass).

(2) When a hole is formed in the FRP outer cylinder member, its strength is reduced, so that the shape of the hole and the number of holes to be installed are limited, and as a result, the improvement of pressure release characteristics is limited.

(3) The FRP itself has poor workability, and in order to prevent the strength from being lowered, it is necessary to precisely process the holes, which takes time to process and leads to an increase in the cost of the product.

There is a problem.

In view of the above points, the present invention has an object to provide a lightning arrester of this kind having excellent strength.

[0011]

Means for solving the above-mentioned problems in the present invention is a Z having an insertion hole at the center thereof.
An nO element, a ring-shaped electrode having a similar insertion hole in the center and provided with radial gas discharge holes on the side wall, and a linear FRP insulating core member made of reinforced plastic are prepared. ZnO elements are stacked on the outer circumference of the electrode, and the electrodes are arranged above and below the ZnO elements or between predetermined ZnO elements.
The lightning protection section main body is formed by fixing metal fittings from both ends of the P insulating core member, and the outer peripheral surface of the lightning protection section main body is covered with a jacket.

[0012]

[Function] When a gas is generated due to a short-circuit accident or the like inside the lightning arrester, the gas is generated on the inner diameter side (insertion hole side) of the ZnO element.
In this case, the generated gas passes through the gap between the insertion hole and the FRP insulating core member and is squirted to the outside through the gas discharge hole of the electrode 4 by breaking the envelope. An arc is generated by the ejection of the ionized gas, short-circuiting the upper metal fitting and the lower metal fitting, and transferring the internal short-circuit of the lightning arrester to the outside to prevent the lightning arrester from exploding.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the embodiments shown in FIGS. FIG. 1 is a vertical sectional front view of an embodiment of the present invention, FIG. 2 is a perspective view of an electrode, and 1 is an FRP insulating core member made of reinforced plastic (FRP), which has a cylindrical shape. A ZnO element 2 has an insertion hole 2'for inserting the core member 1 in the center thereof. Reference numerals 3 and 3'indicate upper and lower metal fittings made of a metal material, and reference numeral 4 denotes electrodes, which have a ring shape, have substantially the same outer diameter and inner diameter as the ZnO element 2, and are provided on the side walls in the radial direction as shown in FIG. It has a gas discharge hole 4 '. 5 is a disc spring,
Reference numeral 6 indicates a weather resistant, outer cover made of an insulating member.

For assembly, one end of the FRP insulating core member 1 is screwed into the lower metal fitting 3, the disc spring 5, the electrode 4, and the ZnO element 2 are sequentially inserted from the upper end of the FRP insulating core member 1, and the ZnO element 2 is set in a predetermined manner. After stacking the layers, the electrode 4 is inserted, and the ZnO element 2 is stacked on the electrode 4. If necessary, this is repeated and finally the electrode 4 and the disc spring 5 are inserted, and the upper metal fitting 3'is screwed onto the upper end of the FRP insulating core member 1 to form the lightning protection body. The outer peripheral side of this lightning protection unit main body is covered with a jacket 6 formed by a molding or heat shrinking means as in the conventional case.
As the material of the outer cover 6, epoxy resin or EP rubber is used as the mold type, and heat shrinkable polymer or the like is used as the heat shrinkable material.

Next, the operation will be described. When the lightning arrester fails and gas is generated on the side of the insertion hole of the ZnO element 2, the generated gas is FRP insulating core member 1 and ZnO element 2 as shown by the arrow in FIG. Through the gap between the insertion hole and the inner diameter side of the electrode 4, and the outer cover 6 is ruptured through the emission hole 4'and discharged (jetted) to the outside. Outside the lightning arrester, an arc is generated by this ionized gas, short-circuiting the upper and lower fittings. Therefore, the explosion of the lightning arrester is prevented by transferring the internal short circuit to the outside. When gas is generated on the outer diameter side of the ZnO element, the gas breaks the jacket and is released to the outside.

In the embodiment shown in FIG. 1, since the FRP insulating core member is a cylinder, internal pressure does not occur in the member, so it is sufficient to design it so as to withstand only bending strength and tensile strength.

The FRP insulating core member may be formed as a cylinder. When a cylinder is used, bending rigidity (second moment of area) increases, but internal pressure is generated, so it is necessary to consider strength. On the other hand, in the case of a cylinder, the bending rigidity is lower than that of a cylinder, and the displacement becomes large when a bending moment occurs, but by interposing disc springs on the top and bottom,
It is possible to prevent an excessive force from being generated in the ZnO element by absorbing the displacement.

Further, the electrode having the gas discharge hole is mainly formed of a metal or the like by penetrating holes of arbitrary shape and number from the inner diameter side to the outer diameter side, and this hole is also used as a manufacturing space. The outer cover member may be enclosed.

[0019]

As described above, according to the present invention, since the FRP insulating core member is arranged at the center of the ZnO element and the gas is released through the gas release holes of the electrodes separately provided,
Since it is not necessary to form any holes in the FRP insulating core member that is a strength member, strength defects or the above-mentioned problems caused by the strength defects are all solved by providing gas discharge holes in the conventional FRP outer cylinder member. .

Further, since the gas discharge hole is provided in the metal electrode, the workability is good, and therefore, any shape and number can be appropriately selected and provided in consideration of the pressure release characteristic, and the pressure release characteristic is improved. , As well as the cost of processing the emission holes is reduced.

Further, as compared with the conventional one in which the ZnO element is housed in the FRP outer cylinder member, the size in the radial direction can be made smaller, the lightning arrester as a whole can be made smaller and lighter, and the cost can be reduced. And so on, it is extremely effective.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of an embodiment of the present invention.

FIG. 2 is a perspective view of an embodiment of the electrode of the present invention.

FIG. 3 is a vertical sectional front view of a conventional example.

[Explanation of symbols]

1 ... FRP insulating core member, 2 ... ZnO element, 3 ... lower metal fitting, 3 '... upper metal fitting, 4 ... electrode, 4' ... gas release hole, 5
… Belleville springs, 6… Coats.

Claims (1)

Claim: What is claimed is: 1. A ZnO element having an insertion hole in the center thereof,
A ring-shaped electrode having a similar insertion hole in the center and a radial gas discharge hole provided on the side wall, and a linear FRP insulating core member made of reinforced plastic were prepared.
ZnO elements are stacked on the outer periphery of the insulating core member, and
The electrodes are arranged above and below the O element or between predetermined ZnO elements, and the ZnO element and the electrodes are fixed from both ends of the FRP insulating core member with metal fittings to form a lightning protection body, and an outer peripheral surface of the lightning protection body. A polymer insulator type lightning arrester, which is characterized by covering the inside with an outer cover.