JPH073538Y2 - Lightning arrester - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an explosion-proof lightning arrester with a current limiting element built-in,
It is used by arranging it on a power transmission / distribution line such as an overhead power transmission line tower or an urban distribution line pillar.

(Prior Art) Insulators are installed in power transmission and distribution lines of overhead power transmission line towers and city distribution line poles, and are used by being connected to some of the above-mentioned towers and part of the utility poles, or used in indoor switchboards. It is generally known that a surge arrester is installed on the overhead power transmission line tower, the city distribution line pillar, and the indoor switchboard to protect the electrical equipment that constitutes them.

Therefore, when a lightning strike strikes, the lightning arrestor operates to ground the lightning surge to the ground, and the surrounding electrical equipment is protected from this surge voltage.As a result, the damage to these electrical equipment is minimal, and power failure or interruption of power transmission is interrupted. The current situation is that the incidence of such accidents is decreasing.

However, as mentioned above, the protection from the surge voltage of the surrounding electrical equipment installed in the overhead power transmission line towers etc. should be largely satisfied as a result of focusing on the improvement of the arrester performance and the proper arrangement of the protection equipment. However, apart from this, new problems have become apparent. That is, a direct lightning strike is applied to a lead wire connected to an overhead power line installed in the overhead power transmission line tower or an urban distribution line pillar and an electric device in an indoor switchboard, and as a result,
Occurrences of disconnection accidents of these overhead power lines and the like often resulted in power outages, and this repair work required a large number of personnel and expenses.

For this reason, it is required that the insulator installed on the overhead transmission line steel tower, the overhead distribution line installed in the city distribution line pole, etc., and having the lightning protection function even in the insulator for connecting and supporting the surrounding electric equipment. Therefore, various developments are being made to meet the demand.

Various types of lightning arresters with a built-in lightning arrester (hereinafter referred to as lightning arrestors) have been proposed. One example thereof is a lightning arrester having the configuration shown in FIG.

Fig. 2 is a half longitudinal sectional view, with openings (1a) at both ends.
(1b) is provided, and a cylindrical insulator body (1) made of an insulating material such as porcelain or glass having an umbrella portion (1c) formed on the outer peripheral surface has a low resistance to surge voltage and a distribution line. The plurality of current limiting elements (2), which are resistors having a high resistance to normal ground voltage, which are mainly zinc oxide and have excellent non-linearity, are housed in a laminated form, and the opening is formed. (1a) has fasteners (4) that electrically connect to the electric wire (3) on the track side
The other opening (1b) is covered with a support metal fitting (5) so as to hermetically seal each opening (1a) (1b).

An electrode terminal (7) electrically connected to the fastener (4) via a coil spring (6) is inserted into the opening (1a), and the electrode terminal (7) and the insulator body are further inserted. A coil spring (8) is installed between the uppermost current limiting element (2) housed in (1) in a laminated manner, and thereby, in the axial direction with respect to the plurality of current limiting elements (2). A holding force is given and the two are electrically connected.

On the other hand, the opening (1b) at the other end is sealed with a sealing metal fitting (18) so as to maintain the airtightness in the insulator body (1), and this and the lowermost current limiting element (2). And a coil spring (9) for electrically conducting the opening (1b) and the supporting metal fitting (5) covered with the opening (1b), and further transmitting and distributing power to the supporting metal fitting (5). A support (10) for connecting and supporting the line is fitted.

The track-side electric wire (3) is designed to be held in a state of being electrically connected to the fastener (4) as described above, but it is provided inside the cover (11) that encloses the entire fastener (4). It is designed to be held between the tightening plate (13) screwed to the screw rods (12) (12) and the upper part of the fastener (4). The screw rods (12) (12) are screwed on the upper part of the fastener (4), and the screw rods (12) (12) are provided with nuts (14) for fastening the tightening plate (13). It is screwed.

Reference numeral (15) is a solid desiccant such as silica gel (SiO ₂ · nH ₂ O), which is a metal holding plate disposed between the uppermost current limiting element (2) and the coil spring (8). It is fixed at (16).

The conventional lightning protection insulator has the above-mentioned configuration, but when an abnormal voltage is generated in the insulator body (1) due to a lightning surge due to a lightning strike on the power transmission and distribution line, the current limiting element (2) incorporated therein.
If the resistance value becomes low and the abnormal voltage disappears, the current limiting element (2) returns to the high resistance value and interrupts the follow-up current to protect peripheral devices from lightning surges and the like.

(Problems to be solved by the invention) Although the conventional lightning protection insulator has the above-mentioned configuration, there is a lightning strike on the power transmission and distribution lines, or the design withstanding capacity of the current limiting element (2) due to direct lightning strikes on the lightning protection insulator. When a surge voltage exceeding 0.1 is generated, the current limiting element (2) may be destroyed.

Then, this breakdown is a penetration breakdown, or a flashover occurs on the surface of the current limiting element (2), and the operating voltage of the transmission and distribution line or the ground voltage is short-circuited at the current limiting element (2) part, and the internal pressure is generated by the high-temperature arc. Rise, and as a result, the insulator body (1) bursts and breaks.
This is because a large amount of high-pressure gas is generated and the internal pressure in the insulator main body (1) rapidly rises.

Therefore, it is necessary to take measures to deal with the above situation, but in the above-mentioned lightning protection insulator, the current limiting element (2)
Porcelain insulator body (1) to maintain and maintain the weather resistance of
Since the inside has a sealed structure, when the internal pressure in the insulator body (1) suddenly rises, there is no means or structure for releasing this pressure, and the insulator body (1) is inevitably ruptured and destroyed and explodes. The result was scattering, and when used on an urban power transmission and distribution line, there was a dangerous situation that could lead to personal injury and damage to peripheral equipment.

In short, there is a problem in that the conventional lightning protection insulator does not adopt a structure for releasing the high temperature and high pressure gas that is rapidly generated in the insulator body (1).

The present invention was devised in view of the above points,
Even if a high temperature and high pressure gas is suddenly generated in the insulator body (1) due to a surge voltage exceeding the design withstanding capability of the current limiting element (2) at the time of lightning strike, it is quickly released, causing the lightning protection insulator to burst or break. An object is to provide an explosion-proof lightning protection insulator that can prevent an explosion.

(Means for Solving the Problem) As a lightning arrestor for achieving the purpose of forward leaning, a current limiting element is housed and fixed in a cylindrical insulator body having both ends opened, and a line is provided at one end opening of the insulator body. The side electrode terminal is inserted, and the other end opening is sealed with a sealing metal fitting, and the line side electrode terminal and the line side electric wire are electrically connected to the opening where the line side electrode terminal is inserted. In addition, in a lightning protection insulator in which the other end opening in which the sealing metal fitting is sealed is capped with a supporting metal fitting, a pressure release port is formed in the insulator body. A structure in which a heat-shrinkable tube is fitted around the outer circumference is adopted.

(Operation) Since the present invention adopts the configuration as described above, there is a lightning strike on a power transmission and distribution line, or a surge voltage exceeding the designed withstanding capability of the current limiting element is generated due to a direct lightning strike on the lightning protection insulator, Is destroyed and a large amount of high-temperature, high-pressure gas is generated, and even if the internal pressure inside the insulator body rises sharply, a part of the heat-shrinkable tube is ruptured through the pressure release port formed in the insulator body, Since it is released into the atmosphere, it can prevent the main body of the insulator from being destroyed and explode, and not only protect the lightning insulator from damage and scattering, but also protect peripheral equipment.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to FIG. 1 which is a half longitudinal sectional view of a lightning arrester according to the present invention.

First, the structure of the lightning arrester according to the present invention will be described with reference to FIG. 1. The same names as those of the structure of the conventional lightning arrester will be designated by the same reference numerals. Openings on both ends (1a)
(1b) is provided, and pressure release ports (17) (17) for rapidly releasing high-temperature, high-pressure gas generated by surge voltage exceeding the design withstanding capacity of the current limiting element to be described later at the time of lightning strike are arranged in the circumferential direction. Inside the insulator body (1) made of an insulating material such as a cylindrical porcelain or glass with a phase difference of 180 degrees,
Multiple current limiting elements, which are resistors with excellent non-linearity mainly composed of zinc oxide, which have low resistance to surge voltage and high resistance to normal ground voltage of transmission and distribution lines ( 2) ...
Are housed in a laminated manner, and the fitting (4) for electrically connecting to the line side electric wire (3) is housed in the opening (1a), and the support fitting (5) is arranged in the other opening (1b). Each opening (1
a) Cap (1b) so that it is hermetically sealed.

A plurality of umbrella parts (19) are provided on the outer circumference of the insulator body (1).
A heat shrinkage based on a thermoplastic polymer (eg polyethylene) that has formed a) and has been cross-linked by high energy irradiation or chemical methods, the cross-linking of which the polymer has elastic properties at temperatures above its normal melting point. The heat-shrinkable tube (19) made of a flexible material is coated to enhance the airtightness inside the insulator body (1) and to protect it from external pressure.

An electrode terminal (7) electrically connected to the fastener (4) via a coil spring (6) is inserted into the opening (1a), and the electrode terminal (7) and the insulator body are further inserted. A coil spring (8) is installed between the uppermost current limiting element (2) housed in a laminated manner in (1), whereby an axial direction with respect to a plurality of current limiting elements (2). And a conductive force between them. On the other hand, the opening (1b) capped with the support fitting (5) is electrically connected between the lowest current limiting element (2) and the support fitting (5) capped with the opening (1b). And a coil spring (9) which is sealed by a sealing metal fitting (18) for electrically conducting and electrically contacts with this and is further connected,
The support fitting (5) is fitted with a support body (10) for connecting and supporting a transmission / distribution line or a lead wire.

The track-side electric wire (3) is designed to be held in a state of being electrically connected to the fastener (4) as described above, but it is provided inside the cover (11) that encloses the entire fastener (4). It is configured to be held between the tightening plate (13) screwed to the screw rods (12) (12) and the upper part of the fastener (4).

The screw rods (12) (12) have one end screwed on the upper part of the fastener (4) and the other end fixed to the inner surface of the cover (11). ) Is screwed with a nut (14) for tightening the tightening plate (13).

Reference numeral (15) is a solid desiccant such as silica gel (SiO ₂ · nH ₂ O), which is a metal holding plate disposed between the uppermost current limiting element (2) and the coil spring (8). The reference numeral (20) is an adhesive cement agent filled between the fastening fittings (4) and the support fittings (5), which are secured to both ends of the insulator main body (1), and are fixed by (16). Reference numeral (21) is a sealing packing attached to each of the illustrated positions, and reference numeral (22) is an adhesive (hot melt resin) to be filled between the outer periphery of the insulator body (1) and the heat-shrinkable tube (19). (22).

The configuration of the lightning arrester according to the present invention is as described above.As is generally known, this lightning arrester is installed on the transmission and distribution lines or indoor distribution lines installed on overhead power transmission line towers and city distribution line poles. Although it is installed and used, if there is a direct lightning strike on the power transmission and distribution line or the lightning protection insulator and an abnormal voltage due to a lightning surge occurs, a surge voltage exceeding the designed withstand current flows through the current limiting element (2) of the lightning protection insulator, The current limiting element (2) is destroyed to generate a large amount of high temperature, high pressure gas. However, this gas acts on the heat-shrinkable tube (19) through the pressure release ports (17) (17) formed in the insulator body (1), and a part of the heat-shrinkable tube (19) having elasticity. It is destroyed by the action of high temperature and high pressure and released into the atmosphere.

In this way, even if a high-temperature, high-pressure gas is suddenly generated in the insulator body (1) due to a surge voltage exceeding the designed withstanding capacity of the current limiting element (2) during a lightning strike, it can be quickly released. It is possible to prevent the insulator body (1) from bursting or exploding due to destruction.

(Effects of the Invention) According to the lightning protection insulator of the present invention, the high-pressure and high-pressure gas generated when the current limiting element is broken is released by the pressure relief port formed in the insulator body that houses and fixes a plurality of current limiting elements. Since this breaks the heat-shrinkable tube and releases it into the atmosphere, it is possible to prevent the main body of the insulator from being destroyed and the explosion accident.

Therefore, there is no effect on the electrical equipment around this lightning protection insulator, and since the outer periphery of the insulator body is covered with a heat-shrinkable tube, the airtightness inside the insulator body is also sufficiently maintained. This has the effect of preventing moisture absorption deterioration of the flow element.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a half longitudinal sectional view showing an embodiment of a lightning arrester according to the present invention, and FIG. 2 is a half longitudinal sectional view showing a conventional lightning arrester. The names of the symbols are as follows. (1) …… Insulator main body, (2) …… Current limiting element, (3) …… Line side wire, (4) …… Clamping fitting, (5) …… Supporting fitting,
(6) (8) (9) ...... coil spring, (7) ...... electrode terminal, (10) ...... support, (11) ...... cover, (12) ......
Screw rod, (13) …… tightening plate, (14) …… nut,
(15) ... desiccant, (16) ... metal holding plate, (17) ...
… Pressure release port, (18) …… Sealing fitting, (19)… Heat-shrinkable tube, (19a)… Heat-shrinkable tube cap, (20)
…… Cement agent, (21) …… Packing, (22) …… Adhesive.

Claims (1)

[Scope of utility model registration request] 1. A current limiting element is housed and fixed in a cylindrical insulator body having both ends opened, a line side electrode terminal is inserted into one end opening of the insulator body, and a sealing metal fitting is provided at the other end opening. In addition to sealing, the opening into which the line-side electrode terminal is inserted is electrically connected to the line-side electrode terminal and the line-side electric wire, and a fastener for enclosing them is further provided, and the sealing metal is further provided. A lightning protection insulator in which a support fitting is capped at the other end opening which is sealed, characterized in that a pressure release port is bored in the insulator body and a heat-shrinkable tube is fitted on the outer periphery thereof. Lightning arrester.