JPS6343301A - Explosion-proof porcelain-less arrestor - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a lightning arrester used in power generation and substations and power transmission and distribution lines.

[Conventional technology]

Zinc oxide devices with excellent nonlinearity have now appeared.

Zinc oxide arresters are now the most commonly used new lightning arresters. Zinc oxide lightning arresters have been mainly installed at substation transformers, line entrances, and main buses.

Based on these achievements, it is expected to be applied not only to substations but also to power transmission and distribution lines as a lightning arrester to prevent reverse flash circuits during lightning strikes. As one of the applicable laws,
-35984 has been proposed. The structure of a lightning arrester is also an example of an arrester element enclosed within an insulating case.
-48588 and Utility Model Application Publication No. 59-Q3502.

[Problem that the invention seeks to solve]

Lightning arresters applied to power transmission and distribution lines usually handle a lightning strike current of 100 V.
, waveform 2×7oμS reverse flash current, 20KA as a direct lightning strike
, 2×70 μS, but in the case of long-wave tail lightning actually measured during winter lightning, etc., there are cases where the time is more than several milliseconds to several tens of milliseconds.

When this direct lightning strike occurs, the lightning arrester element (zinc oxide element)
If porcelain or the like was used, there was a risk of damage or falling due to burnout, ground fault current flowing, rise in the internal pressure of the arrester, uneven heat from the arc, etc. On the other hand, as shown in Japanese Utility Model Publication No. 60-35984, in which an elastic body such as rubber is provided instead of porcelain, a discharge gap is naturally generated between the elastic body and the cap fitting. In this method, the location where the gas is generated is not fixed, and there is a risk that the rubber will break or fall if its elastic limit is exceeded. In Japanese Utility Model Publication No. 57-48588 and Japanese Utility Model Application Publication No. 59-3502, the pressure relief hole is not specified, and only depends on the reliability of the device.

An object of the present invention is to provide an explosion-proof lightning arrester that does not use porcelain.

Measures to solve problem C] What about rising arrester internal pressure and uneven heat? An internal pressure release device is installed in the mounting bracket for the internal pressure release section, and a release break hole is added to allow the excessive internal pressure to penetrate the insulator coating and release the internal pressure to the outside. The parts other than the release hole are glued to the metal fittings, so they will not fall. On the other hand, 'a
The lightning element is fixed inside an insulating tube, and is designed to prevent it from falling even when ground fault current is applied.

The present invention eliminates the need for a porcelain insulator tube by replacing the conventional explosion-proof construction with a pressure relief valve with a small-diameter internal pressure relief hole between the insulator coating surface and a part of the terminal fitting of the lightning arrester. It is in.

[Effect]

The release rupture hole is supplied with excessive internal pressure from the internal pressure release path,
The internal pressure seal surface exceeds the allowable stress value and breaks. The contact surface with a metal fitting that does not have a discharge hole is fixed without breaking, and there is no falling movement.

〔Example〕

FIG. 1 shows an embodiment of the invention. iI2! A lightning device 1 electrical element 10 (consisting of a zinc oxide element, etc.) is placed in a cylindrical element guide 8 via a spring 7 on the upper side and a screw 11 on the lower side using an upper mounting bracket 6. It is enclosed via the lower mounting bracket 6'. The element guide 8 is fixed to the mounting brackets 6, 6' by tightening the screws 5, 5'.

Furthermore, the screws 5 are tightened to the mounting brackets 6, 6' through the insulating cylinder 9 to provide strength as an iIM device. M [li9 is made of an insulating material such as ERP or epoxy resin, but since these materials have the required leakage distance for stain resistance and anti-tracking performance, it is necessary to use an insulating tube. The insulator 1 is brought into close contact with the surface of the lightning arrester 9 to provide stain resistance to the surface of the lightning arrester. Insulator 9
Due to the adhesion force, airtightness between the mounting brackets 6 and 6' surfaces of the insulating tube 9 is ensured.

The insulator 9 is made of polyethylene or the like which is heat-shrinkable and has elastic properties by cross-linking it by high-energy irradiation or chemical methods.

In order to strengthen the adhesive airtight portion, the insulator 1 is attached to the mounting fittings 6, 6' via the fixing fitting 15.

The insulator 1 is tightened and compressed like a normal packing structure to improve airtightness. On the other hand, in order to prevent condensation due to residual moisture in the internal elements, a dry substance 20 such as dry air or SFe gas is sealed, and an airtight plug 22 is provided at the end face to form a generously sealed structure. A dry adsorbent 21 is enclosed.

In the operating state, if the element 10 were to burn out due to excessive energy absorption, the pressure inside the element guide 8 would rise and the internal pressure would rise.

In this case, the pressure relief hole is about 10 to 20 m long, and if the inner thickness is 1 to 2 as, a stress of about 30 kg/m" will occur at an internal pressure of several 100 kg/ffl, exceeding the elastic limit of the insulator 1. This state is shown in FIG. 2(a), and the state after the destruction is shown in FIG. 2(b).

The generated internal pressure discharge arc is discharged to the outside via the arc guides 3, 3', and is ultimately short-circuited to the outside, thereby suppressing the rise in internal pressure. FIG. 3 shows an example in which lightning arresters according to the present invention are arranged in parallel via mounting fittings 19 and 19' of power transmission line support insulators.

〔Effect of the invention〕

According to the present invention, it is possible to realize lightweight type A porcelain that will not explode or scatter even if a ground fault current is applied.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is a partial sectional view of an embodiment in which a lightning arrester according to the present invention is installed together with a power transmission line support insulator. 1... Insulator.

Claims (1)

[Scope of Claims] 1. In a lightning arrester using an insulator such as elastic rubber for the container, the insulator is tightened by a mounting bracket and a fixing bracket of the lightning arrester, a discharge hole is installed in the mounting bracket, and the lightning arrester is made of elastic rubber. An explosion-proof type insulator-less lightning arrester characterized by using an insulator such as the above as a pressure relief valve. 2. An explosion-proof insulator-less lightning arrester according to claim 1, characterized in that an airtight plug is built into the lower mounting bracket. 3. An explosion-proof insulator-less lightning arrester according to claim 1, wherein the lightning arrester is provided via a power transmission line support insulator mounting bracket.