JPH0272517A - Lightning protecting insulator - Google Patents

Abstract

PURPOSE:To prevent the crack development to an insulator body and improve the bursting characteristic in the case of an abnormal overcurrent short circuit by adhering the outer circumferential parts of caps porcelain cylinder, a container of a to the upper and lower end parts of a lightning protecting element, respectively using an inorganic glass, and air-tightly holding the element. CONSTITUTION:A lightning protecting element 4 is disposed within a porcelain cylinder 3 through a reinforcing member, for example, consisting of a ceramic cylinder 5 made of alumina and a fire resisting inorganic fiber 6, and an upper cap 8-1 and a lower cap 8-2 are air-tightly sealed to the taper form upper end surface 7-1 and lower end surface 7-2 of the porcelain cylinder 3. Thus, a breakage position in the bursting can be localized on the caps for tightly receiving a ZnO element 4. Hence, the extension of cracks to an insulator body is prevented, and the bursting characteristic in the case of an abnormal excess current short circuit can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a lightning arrester having a built-in lightning arrester element, and particularly relates to a lightning arrester having good pressure relief characteristics in the event of an abnormal overcurrent short circuit.

(Prior Art) Conventionally, lightning arrester insulators have been used that reduce failures caused by direct lightning strikes while maintaining the power transmission line gripping function by adding a lightning protection function to the insulator.

- As an example, the applicant disclosed in Japanese Patent Application Laid-Open No. 57-160555 a lightning arrester in which a ZnO element is integrally fixed inside the insulator with inorganic glass as a means to protect the insulator itself from excessive current during a lightning strike. ing.

This lightning arrester had an excellent airtight insulation property because the ZnO element and the insulator were integrated with inorganic glass.

(Problem to be solved by the invention) However, in the lightning arrester having the above structure, Zr+0
There was a problem in which good explosion-proof characteristics could not be obtained in an explosion-proof (pressure release characteristic) test that simulates a case where the inside becomes conductive due to deterioration of the element and abnormally large currents such as those caused by lightning are applied to the same part. That is, when an abnormally large current is applied, an abnormal temperature rise or internal pressure increase in the ZnO element causes crank extension not only to the ZnO element housing but also to, for example, the cap or head of the insulator.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a lightning arrester that has good lightning arresting function and airtight insulation properties, and can prevent cracks from propagating to the insulator body even during explosion protection.

(Means for Solving the Problems) The lightning arrester of the present invention has a structure in which a lightning arrester is airtightly installed in a porcelain inner hole. The lightning arrester element is airtightly held within the porcelain inner hole by bonding the contact surfaces with inorganic glass.

(Function) In the above-mentioned configuration, the ZnO element is not directly sealed to the insulator body, but only the lids disposed above and below the ZnO element are hermetically sealed to the porcelain end using inorganic glass. The explosion-proof position is localized to the lid placed above and below the ZnO element, preventing crank extension to the insulator body and improving pressure relief characteristics in the event of an abnormal overcurrent short circuit.

(Example) FIG. 1 is a partial sectional view showing a suspension type lightning arrester as an example of the lightning arrester of the present invention. In this embodiment, the suspension insulator 1
A porcelain cylinder 3 is provided in the cylindrical part 2 and includes a porcelain inner hole, and a cylindrical lightning arrester element 4 whose main component is ZnO is installed inside the porcelain cylinder 3.
A lightning arrester is formed by providing a plurality of airtight lightning arresters in the cylindrical portion 2.

That is, the lightning arrester element 4 is arranged inside the porcelain cylinder 3 via a reinforcing member made of a ceramic cylinder 5 made of alumina and fire-resistant inorganic fiber 6, and the tapered upper end surface 7-1 of the porcelain cylinder 3 is Upper M8-1 and lower M on the lower end surface 7-2
8-2 is hermetically sealed with inorganic glass 9.

In this embodiment, conductive members 10-1 and 10-2 made of metal and the conductive plate 1 are provided on the outside of the upper lid 8-1 and the lower lid 8-2.
1-1.11-2 and the filler 12, the outer cover 13-1.13-2 made of a conductive material such as metal is connected to the outer cover 13-i.
, 13-2 are caulked into grooves 14-1 and 14-2 provided at the upper and lower ends of the outer periphery of the porcelain cylinder 3. In addition, a conductive spring member 15 is preferably provided between the upper cover 8-1 and the lightning arrester element 4 to ensure continuity between the upper cover 8-1 and the lightning arrester element 4 and to prevent rattling between the two. are doing. The material for the upper lid 8-1 and the lower lid 8-2 is preferably metal or conductive ceramics, but it is also possible to use ceramics by bonding metal or conductive ceramics to a part thereof to form conductive electrodes. Thereafter, the upper lid 8-1 and the cap 16 are electrically connected to each other using a lead wire (not shown), and the lower lid 8-2 and the bottle 17 are electrically connected.
By making it conductive, a suspended lightning arrester was finally obtained.

To obtain the lightning arrester having the above-described structure, a hole is made at a predetermined position in the suspension insulator 1 and the porcelain cylinder 3 is joined to form a porcelain inner hole, or the porcelain cylinder 3 and the suspension insulator 1 are integrally molded. After forming a porcelain inner hole, a lightning arrester element 4, a ceramic cylinder 5, an inorganic fiber 6, and a spring member 15 are provided at predetermined positions within the porcelain cylinder 3 between the upper cover 8-1 and the lower cover 8-2. At this time, it is necessary to apply inorganic glass 9 to the contact surfaces between the upper end surface 7-1 and lower end surface 7-2 of the porcelain cylinder 3 and the upper lid 8-1 and lower lid 8-2 using various methods. As a method of application, conventionally known methods such as directly applying glass powder, applying by spraying, applying in the form of a paste or tape, etc. can be used. Thereafter, the upper lid 8-1 and the lower lid 8-2 are heated while being pressed from both sides to melt the inorganic glass 9. and the porcelain lower end surface 7-2 are hermetically sealed. In addition, in the above-mentioned manufacturing method, the temperature is 800 to 1000°C in an oxidizing atmosphere in advance.
It is more preferable to use a metal lid that has been heated at a temperature of Particularly preferred is its use.

Hereinafter, the results of actually investigating the pressure release characteristics of the suspension type lightning arrester of the present invention will be explained.

In the suspension insulator 1 shown in FIG.
By changing the arrival structure of the lightning arrester stored in the cylindrical part 2,
Samples Nα1 to Nα9 of the present invention shown in Table 1 and a conventional sample in which the entire circumference of the lightning arrester element 4 was sealed with inorganic glass were prepared.

15 for the prepared suspension insulators of the present invention and the conventional example.
KA x O, 2 seconds, 30KA x□, 2 seconds and 50
KAXO, a 2 second pressure release test was conducted and the results were investigated. The results are shown in Table 1. In Table 1, × is 15KAX
In the 0.2 second pressure release test, the cap was chipped and a crack appeared on the head, and Δ was 15^×0.2 seconds, and only the sealed end was destroyed. 30KAX0,
In the 2 second pressure release test, only a part of the cylindrical part had a cap chipped, and the O was set to 50 AXo, and in the 2 second pressure release test, only the sealed end was broken and there was no damage on the cylindrical part. Each shows something.

From the results in Table 1, it can be seen that when the lid and porcelain are sealed at both ends of the lightning arrester of the present invention using inorganic glass, it is 50KA
There was no damage to the cylindrical part even in a pressure release test of 0.2 seconds, whereas when the entire surface of the conventional lightning arrester was sealed with glass, the cap was chipped in a pressure release test of 15KA x □, 2 seconds. A crack may develop and extend to the head.

The present invention is not limited only to the embodiments described above, and numerous modifications and changes are possible. For example, in the above-described embodiment, the adhesive end surfaces of the upper and lower lids and the porcelain cylinder were tapered, but it goes without saying that other shapes may be used.

Further, the reinforcing member may of course have a structure other than the above-described structure as long as it has a reinforcing effect. Furthermore, it is clear that the present invention can be applied not only to suspended lightning arrester insulators but also to insulators of other shapes.

(Effects of the Invention) As is clear from the above description, according to the lightning arrester of the present invention, only the outer periphery of the lid disposed above and below the ZnO element is hermetically sealed with the insulator body using inorganic glass. , the fracture location can be localized on the lid that airtightly houses the ZnO element during pressure release, and as a result, cracks can be prevented from extending to the insulator body.
It is possible to improve the pressure release characteristics at the time of abnormal overcurrent short circuit.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing a suspension type lightning arrester as an example of the lightning arrester of the present invention. 1... Suspension insulator 2... Cylindrical portion 3... Porcelain cylinder 4... Lightning arrester element 5... Ceramic cylinder 6... Inorganic fiber? -1...Top end surface
7-2...Lower end surface 8-1...Top lid 8-
2... Lower lid 9... Inorganic glass 10-1.10-2... Metal member 11-1.11-2... Conductive plate 13-1.13-2... Outer cover 15. ...Spring member 17...Pin 12...Filler 14-1.14-2...Groove 16...Cap

Claims (1)

[Claims] 1. In a lightning arrester having a structure in which a lightning arrester is airtightly installed in a porcelain inner hole, the contact surface between the outer periphery of a lid disposed at the top and bottom of the lightning arrester and the porcelain is bonded by inorganic glass. A lightning arrester characterized in that a lightning arrester element is airtightly held within a porcelain inner hole. 2. The lightning arrester according to claim 1, further comprising a reinforcing member provided between the side portion of the lightning arrester element and the porcelain inner hole.