JP2503339Y2 - Lightning arrester with reduced local electric field concentration - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester which prevents a power failure due to a ground fault by discharging a lightning surge current to the ground and suppressing a rise in a lightning surge potential of a transmission line.

[0002]

2. Description of the Related Art Conventionally, in order to improve the lightning surge discharge withstanding capability of a lightning arrester, a device in which local electric field concentration inside the lightning arrester is relaxed is disclosed in Japanese Utility Model Laid-Open No. 2-116702. In this conventional lightning arrester, as shown in FIG. 4, a plurality of lightning arrester elements 12 that are laminated and joined to each other are provided inside an insulating cylinder 11, and an intermediate electrode 18 having a disc spring 23 built in at one end thereof. Both upper and lower sealing electrodes 1 that are inserted and form a cup shape between both ends thereof.
It is sandwiched and connected between 3. The intermediate electrode 18 has a role of absorbing thermal expansion of the lightning protection element 12 and the like, and exerts a pressing force on the element by the disc spring 23 in order to increase the contact area between the end surface of the element and the sealing electrode 13. The sealing electrode 13
The peripheral edge portion of is fixed to the outer end portion of the insulating cylindrical body 11 by crimping. Then, with respect to the entire length L of the lightning protection element 12, the peripheral edge portion of the sealing electrode 13, the intermediate electrode 18, and the lightning protection element 12 are provided.
The distance Δl from the interface of

[0003]

## EQU1 ## The equipotential lines E are arranged so that the relationship of 0 ≦ Δl / L ≦ 10% is satisfied and the intermediate electrode 1
The local electric field concentration in the vicinity A of the interface between the intermediate electrode 18 and the lightning arrester element 12, which is caused by wrapping around the thickness of 8 is alleviated by utilizing the peripheral edge portion of the sealing electrode 13.

[0004]

However, in this conventional lightning arrester, since the intermediate electrode 18 is arranged in contact with one end side of the sealing electrode 13, the length of the insulating cylindrical body 11 and the lightning arrester element to be housed. It was necessary to determine the length of the peripheral edge corresponding to the total length L of 12 and fix the crown by the sealing electrode 13.
In particular, a row of lightning arrester elements 12 having a short overall length (for example, one lightning arrester element 1
If the thickness of 2 is increased and the number of lightning protection elements 12 is reduced,
The total length of the row of lightning protection elements 12 may be short. ) Is accommodated, as shown in FIG.
In some cases, the relationship of 0 ≦ Δl / L ≦ 10% cannot be maintained, and there is a problem that local electric field concentration cannot be relaxed.

The object of the present invention is to suppress the electric field concentration near the interface between the intermediate electrode and the lightning arrester without being restricted by the position of the peripheral edge of the sealing electrode, and to enhance the discharge withstand capability of the lightning arrester. It is what

[0006]

In order to achieve the above object, according to the present invention, a sealing electrode having both ends of an insulating cylinder covered and fixed, and a plurality of lightning protection elements stacked between the sealing electrodes are provided. , Ri Do and an intermediate electrode of a predetermined thickness having an internal elastic member which is charged between the該避lightning element and lightning protection device, between intermediate
The outer circumference of the electrode is formed in an arc shape, and its outer diameter is the lightning protection element.
The outer diameter is set to be almost the same .

[0007]

In the present invention, the intermediate electrode is inserted between the lightning protection element and the lightning protection element, and the outer peripheral portion thereof is formed in an arc shape, and the outer
Since the diameter is almost the same as the outer diameter of the lightning arrester , the equipotential line runs from both sides of the intermediate electrode by about half the thickness of the intermediate electrode and runs near the interface between the intermediate electrode and the lightning arrester. The local electric field concentration of is relaxed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is embodied in a suspension-type lightning arrester 1 which is suspended from a plurality of supporting arms of a steel tower (not shown) in series and is used to support a transmission line on a lightning arrester 1 at the lower end. An embodiment will be described with reference to FIGS. As shown in FIG. 1, an insulator body 2 of a lightning protection insulator 1 includes a head 3 formed in a cylindrical shape with a lid, and a cap portion 4 formed on the periphery of the head 3.
And a plurality of folds 5 formed concentrically on the inner surface of the cap portion 4 are integrally formed. A cap metal fitting 7 is fitted and fixed to the outer periphery of the head 3 with cement 6. A fitting recess 8 is formed in the cap fitting 7 so that the cap fitting 7 can be engaged with the pin fitting 9 of the lightning protection insulator 1 immediately above.

The upper portion of the pin fitting 9 is fixed inside the head 3 with cement 10, and the lower end thereof is engaged with the fitting recess 8 of the cap fitting 7 of the lightning protection insulator 1 directly below, so that a plurality of lightning protection insulators 1 are provided. They are connected in series. A hollow cylindrical insulating cylinder 11 is integrally formed in the cap portion 4 so as to penetrate the cap portion 4. In this insulating cylinder body 11, two lightning protection elements 12 whose main material is zinc oxide having a non-linear voltage-current characteristic are housed. In addition, sealing electrodes 13 are capped and fixed to the upper and lower edges of the insulating cylinder 11. This sealing electrode 13
Is composed of an external sealing electrode 14 for fixing the insulating cylindrical body 11 to the crown and an internal sealing electrode 15 for closely contacting the lightning protection element 12.

The external sealing electrode 14 is made of a conductive material such as aluminum or copper and is formed in a cup shape, and its peripheral edge portion 15 is fixed by caulking the end edge portion of the insulating cylindrical body 11. Further, the internal sealing electrode 15 is press-connected to the external sealing electrode 14 via the elastic body 16 composed of a coil spring. The internal sealing electrode 15 is made of a conductive material such as an aluminum alloy such as aluminum, duralumin or a copper alloy (phosphorus bronze), iron, nickel, cobalt or an alloy containing chromium, and has a diameter larger than that of the lightning protection element 12 in the center. A recess 17 is formed. Two lightning protection elements 12 are inserted between the central portions of the recesses 17, and an intermediate electrode 18 is interposed between the two lightning protection elements 12.

The intermediate electrode 18 is made of a conductive material such as aluminum or copper, and has a locking collar 20 formed on the outer periphery of a disk-shaped upper electrode plate 19 and a cylindrical portion 22 formed on the outer periphery of the lower electrode plate 21. And the pair of disc springs 2 as elastic members inside the both electrode plates 19 and 21.
3,23 are inserted. Therefore, the lightning protection element 12 is pressed by the intermediate electrode 18 and is closely connected to the internal sealing electrode 15.

A lead wire 24 is connected between the external sealing electrode 14 located at the upper part and the cap fitting 7.
A lead wire 25 connects the external sealing electrode 13 and the pin fitting 9 located at the lower part. Next, the operation of the lightning protection insulator 1 of this embodiment will be described. Now, when an overvoltage of a lightning surge is applied to the power transmission line, a lightning surge current flows to the pin metal fitting 9 of the lightning protection insulator 1 at the lower end, and from the lead wire 25, the lower outer sealing electrode 14, the elastic body 16, and the inner sealing. Stop electrode 1
5, the lower lightning protection element 12, the intermediate electrode 18, the upper lightning protection element 12, the internal sealing electrode 15, the elastic body 16, the upper external sealing electrode 14, from the lead wire 24 to the cap fitting 7,
The lightning insulator 1 on the ground side sequentially flows and is discharged from the steel tower to the ground. At this time, the lightning arrester element 12 reduces the resistance value due to its non-linear voltage-current characteristic to discharge the lightning surge current, and immediately restores the resistance value to restore insulation to the subsequent operating voltage.

With respect to the overvoltage of the lightning surge, the equipotential line E runs substantially horizontally along the bottom plane of the recess 17 at the position near the interface between the internal sealing electrode 15 and the lightning arrester 12, so that the local electric field is concentrated. Does not happen. Also in the vicinity A of the interface between the intermediate electrode 18 and the lightning arrester 12, as shown in FIG. 1, the equipotential line E wraps around the upper and lower end portions of the intermediate electrode 18 by approximately half the thickness of the electrode. Local electric field concentration is mitigated compared to the conventional example that runs sideways at and runs around the entire length.

The present invention is not limited to this embodiment and may be constructed as follows. (1) In this embodiment, an example in which two lightning arrester elements 12 are housed is shown, but the number of lightning arrester elements 12 may be three as shown in FIG. In this case, it is desirable that the two lightning arresting elements 12 on the lower side are laminated and joined so that the contact resistance between the lightning arresting elements 12 is sufficiently low.

(2) In this embodiment, the external sealing electrode 14
Although the example of the sealing electrode 13 including the internal sealing electrode 15 and the internal sealing electrode 15 is shown, the sealing electrode 13 may be composed of one sealing electrode.

[0016]

As described in detail above, according to the present invention, a sealing electrode in which both ends of an insulating cylinder are covered and fixed, a plurality of lightning protection elements stacked between the sealing electrodes, and the lightning protection element are provided. It consists of a middle electrode which is charged to between the lightning protection device, the intermediate conductive
The outer circumference of the pole is formed in an arc shape, and its outer diameter is
Since the diameter is set to be almost the same , the electric field concentration at the interface between the intermediate electrode and the lightning arrester can be relaxed, and the discharge withstand capability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part.

FIG. 2 is a semi-longitudinal sectional view of a suspended lightning arrester.

FIG. 3 is a cross-sectional view of a main part showing another example.

FIG. 4 is a partial cross-sectional view showing a conventional lightning arrester.

FIG. 5 is a partial cross-sectional view showing a conventional lightning arrester.

[Explanation of symbols]

11 insulating cylinder, 12 lightning protection element, 13 sealing electrode, 1
8 Intermediate electrode, 23 Belleville spring as elastic member, A Near the interface between the intermediate electrode and the lightning arrester.

Claims (1)

(57) [Scope of utility model registration request] 1. A sealing electrode in which both ends of an insulating cylindrical body are covered and fixed, and a plurality of lightning protection elements stacked between the sealing electrodes.
Ri Do and a predetermined thickness of the intermediate electrode having a resilient member therein that is charged between the該避lightning element and lightning protection device, the intermediate electrodes
The outer peripheral part of the is formed in an arc shape, and its outer diameter is
Arrester to relieve the localized electric field concentration that is set substantially the same as the diameter.