JPH0224921A - Lightening protection insulator - Google Patents

Abstract

PURPOSE:To prevent a current limiting element from being damaged and flown away as well as the generation of danger that a continuous current can not be blocked by constituting an insulation filler stored in a gap between a pressure resistant insulation cylinder and the current limiting element, of a rubber elastic body. CONSTITUTION:Electrode metal fittings 2, 4 on the earth and charge sides area fitted and fixed to both end of pressure resistant insulation cylinder 1 having pressure releasing hole 1a, while a current limiting element 7 of non- linear type in specifying voltage-current is stored inside the cylinder 1. Both the ends of the element 7 are connected to the fittings 2, 4, while the outer periphery of the cylinder 1 is covered with an insulating cover 13, and an insulation filler 15 is stored inside the gap between the cylinder 1 and the element 7. The filler 15 is constituted of a rubber elastic body with its spring hardrenss being lower than 75Hs (JISA). It is thus possible to surely prevent the element from being damaged and flown away and to surely prevent the generation of danger that a continuous current can not be blocked.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is intended to quickly discharge lightning surge current to the ground when a lightning surge current flows through a power transmission line or distribution line, and to discharge the subsequent follow-on current. This invention relates to a lightning arrester that can suppress and cut off lightning.

[Prior art] As a conventional lightning arrester of this type, for example, Japanese Patent Application Laid-Open No. 61
Structures such as those shown in Japanese Patent Application Laid-open No. 151913 and Japanese Unexamined Patent Publication No. 61-243615 are known. In this conventional configuration, electrode fittings on the grounding side and on the power supply side are fitted and fixed to both ends of a voltage-resistant insulating cylinder having a pressure relief hole, and
A current-limiting element with non-linear voltage-current characteristics is housed inside the voltage-resistant insulating cylinder with a predetermined gap between the inner peripheral surface thereof and the current-limiting element, and both electrode fittings and both ends of the current-limiting element are electrically connected, An insulating jacket is coated on the outer periphery of the voltage-resistant insulating cylinder, and
An insulating filler is housed within the gap.

In a lightning arrester configured in this way, if an unexpectedly large lightning surge current is applied to the current limiting element, the current limiting element becomes conductive, or a flash short circuit occurs on the outer surface of the current limiting element. In this case, the insulating filler is thermally decomposed and gasified by the high-temperature arc generated at this time, and the gas is trapped in the arc path and the minute gap between the current limiting element and the interface of the insulating filler. The pressure becomes extremely high.

For this reason, in conventional lightning arrester insulators, the voltage-resistant insulating tube is formed of a pressure-resistant reinforced resin such as FRP, and its strength is only 2.0001q even considering the decrease in strength due to the formation of pressure relief holes.
r/- or more, and is configured so that there is a large strength difference between the insulating filling material and the insulating jacket, which have a strength of about 1001qr/c+fl, and the high-voltage scum is released between the high-voltage insulations. The insulating filling material and insulating jacket were ruptured at approximately the center of the hole, and the insulating material was released to the outside.

[Problems to be Solved by the Invention] However, in this conventional lightning arrester, the hardness of the insulating filler accommodated in the gap between the voltage-proof insulating tube and the current limiting element is not specified. If an insulating filler with a high rated temperature is used, the insulating filler will not be easily deformed toward the pressure relief hole side of the pressure-resistant insulating cylinder when the high-pressure gas is generated.
There is a problem in that the pressure-resistant insulating tube may be destroyed due to an abnormal increase in internal gas pressure, and the current limiting element may be damaged and scattered.

In addition, in the conventional lightning arrester, when the insulating filler is thermally decomposed and gasified by a high-temperature arc, a carbonized thermal decomposition product is generated without being completely gasified, and the thermal decomposition product becomes conductive. There was a problem in that there was a risk that a path would be formed and the subsequent flow could not be blocked.

This invention was made by focusing on the problems that exist in the conventional technology, and is caused by the high temperature arc generated when an unexpectedly large lightning surge current is applied to the current limiting element. The insulation filler is thermally decomposed and gasified,
To provide a lightning arrester which prevents a voltage-resistant insulating cylinder from being destroyed even if the internal pressure of the voltage-resistant insulating cylinder increases rapidly and can reliably prevent the risk of damage and scattering of a current-limiting element. In addition, the carbonized pyrolysis products generated when the insulating filler is pyrolyzed by the high-temperature arc do not remain as they are, and the pyrolysis products form a conductive path. The object of the present invention is to provide lightning protection glass that can reliably prevent the danger of being unable to block follow-on current.

Means for Solving the Problem] In order to achieve the above object, in the lightning arrester of the present invention, an insulating filler housed in the gap between the voltage-resistant insulation and the r@streamon, Spring hardness is 75Hs (J
IS A) It is constructed from the following rubber-like elastic material.

Further, as the rubber-like elastic body, it is preferable to use one containing 20 to 50% by weight of trihydrated alumina.

In the lightning arrester configured as described above, an unexpectedly large lightning surge current is applied to the current limiting element, and the insulating filler is thermally decomposed and gasified by the high-temperature arc generated at that time. When the internal pressure of the pressure-resistant insulation cylinder suddenly increases, the insulation filler made of a rubber-like elastic material with low spring hardness is easily deformed toward the pressure relief hole of the pressure-resistant insulation cylinder, and the pressure relief hole Almost in the center! The insulating filling material and insulating jacket are ruptured nearby, and high-pressure gas is released to the outside. Therefore, there is no risk that the voltage-resistant insulating tube will be destroyed and the current limiting element will be damaged and scattered.

In addition, when the insulating filler is thermally decomposed and gasified by the high-temperature arc, if a carbonized thermal decomposition product is generated without being completely gasified, the carbon product is contained in the insulating filler. It is oxidized and reduced by the catalytic action of trihydrated alumina, and the release of water of crystallization generates a water vapor flow that carries the remaining carbon products from the interior of the lightning arrester to the outside. There is therefore no risk of non-blocking of the follow-on flow due to the formation of conductive paths due to carbon products.

[Example] Hereinafter, an example of a lightning arrester embodying the present invention will be described in detail based on the drawings.

As shown in FIG. 1, the voltage-resistant insulating cylinder 1 is formed into a cylindrical shape from a voltage-resistant reinforced resin such as FRP.

A cylindrical ground-side electrode fitting 2 is airtightly fitted and fixed to the outer circumference of the upper end of the voltage-resistant insulating cylinder 1 with an adhesive 3, and is attached to a mounting adapter on the support arm of the tower (not shown) on the outer circumference. A flange portion 2a is integrally formed to protrude. The charging side has a cylindrical shape with a bottom! The electrode fitting 4 is airtightly fitted and fixed to the outer circumference of the lower end of the voltage-resistant insulating cylinder 1 with an adhesive 5, and on the lower surface thereof, an arc horn on the energizing side provided on the power transmission line side (not shown) and a predetermined air discharge Brackets 4a for attaching the ground side arc horn are integrally formed to protrude so as to face each other with a gap therebetween.

The fitting cylindrical portion 4b is formed on the inner bottom surface of the electrode fitting 4 on the power supply side, and a conductive metal fitting 6 on the power supply side is fitted and fixed therein. A plurality of current limiting elements 7 mainly made of zinc oxide with non-linear voltage-current characteristics are stacked in series and placed on the conductive metal fitting 6 on the power supply side, and are placed inside the voltage-resistant insulating cylinder 1. It is housed with a predetermined gap between it and the inner peripheral surface.

A ground-side conductive metal fitting 8 having a cylindrical shape with a bottom is supported on the upper end surface of the current limiting element 7, and this conductive metal fitting 8 also serves as a spring holder.

For tightening, the ring 9 is screwed onto a threaded portion 2b provided on the inner circumferential surface of the electrode fitting 2 on the ground side, and the intermediate conductor 10 is fitted inside the threaded portion 2b. A coiled spring 12 having an energizing shunt 11 is interposed between the conductive metal fitting 8 on the grounding side and the intermediate conductor 10, and the action of this spring 12 causes the current limiting element 7 to It is held between the conductive metal fittings 6.8 with a predetermined pressing force.

As shown in FIGS. 1 to 3, a plurality of pressure relief holes 1a are formed on the circumferential surface of the voltage-resistant insulating cylinder 1 at predetermined intervals, and are circular or elongated. The insulating jacket 13 is coated and molded around the outer periphery of the voltage-resistant insulating tube, and a large number of insulating folds 13a are integrally provided on the outer periphery of the insulating jacket 13. This insulating jacket 13 is formed so as to extend over the outer peripheral surfaces of both the tjfl fittings 2 and 4, and is intended to improve the airtightness between it and the electrode fittings 2.4. Further, the insulating jacket 13 is formed by entering into each pressure relief hole 1a on the pressure insulating cylinder 1.

The insulating seal #, 14 is molded to cover the electrode fitting 2 on the ground side when molding the insulating jacket 13, and the upper end opening of the electrode fitting 2 on the ground side is sealed by the insulating seal 14. The insulating filler 15 is the insulating sealing body 14
During molding, the tightening is done through a passage 9a provided on the outer periphery of the ring 9.

It is injected into the gap between the inner circumferential surface of the voltage-resistant insulating cylinder 1 and the outer circumferential surface of the current limiting element 7, and is molded so as to close the gap.

In this embodiment, the insulating jacket 13 is made of a rubber-like elastic body having a spring hardness of 80Hs (JIs A) or less, and the insulating sealing body 14 and the insulating filler 15 are
is made of a rubber-like elastic body with a spring hardness of 75Hs (JIS A) or less. Note that this insulating jacket 13
The spring hardness of the insulating sealing body 14 and the insulating filler 15 is within the range of 50 to 80 Hs, and the spring hardness of the insulating sealing body 14 and the insulating filler 15 is within the range of 40 to 80 Hs.
It is preferable to set it within the range of 70Hs. Moreover, in this embodiment, in particular, the insulating sealing body 14 and the insulating filler 15
Trihydrated alumina as a water-containing inorganic compound is homogeneously dispersed and contained in the rubber-like elastic body at a weight ratio of 20 to 50%.

Note that since lightning arresters are generally required to have long-term durability and reliability for 20 to 30 years, the rubber elastic bodies of the insulating jacket 13, the insulating seal 14, and the insulating filler 15 are made of materials with excellent weather resistance. Silicone rubber - EPM, EPDM, chlorosulfonated polyethylene (C3M), fluoro rubber (FPM)
), ethylene propylene rubber, and the like. In addition, especially when using ethylene propylene rubber, the weight ratio is 0.02 to 0.05.
% of vinyltriethoxysilane or mercaptopropyltrimethoxysilane and 0.03 to 0.15% by weight
It is preferable to homogeneously disperse and contain the carbon, and in this case, the layer exhibits excellent weather resistance.

Next, the operation of the lightning arrester constructed as described above will be explained.

Now, with this lightning arrester installed on the steel tower, when a lightning surge current flows through the power transmission line, the current flashes over from the arc horn on the transmission line side (not shown) to the arc horn on the lightning arrester side, and the lightning surge current flows through the power transmission line. tf! The metal fitting 4, the conductive metal fitting 6 on the side of the section, the current limiting element 7, the conductive metal fitting 8 on the ground side, the shunt 11, the intermediate conductor 10, and the clamp flow through the ring 9 to the electrode metal fitting 2 on the ground side, and further, as shown in the figure. Do not flow through the mounting adapter to the tower and be discharged to the ground. Then, the subsequent flow is caused by the arc horn and the current limiting element 7.
It is suppressed and blocked by.

In addition, in this lightning arrester, if an unexpectedly large lightning surge current is applied to the current limiting element 7 and the current limiting element 7 becomes conductive, or if a flash short circuit occurs on the outer surface of the current limiting element 7. In this case, the insulating filler 15 is thermally decomposed and gasified by the high heat or high-temperature arc generated at this time, and the gas is sealed in the arc path and the minute gap between the current limiting element 7 and the interface of the insulating filler 15. In a state of being trapped,
The internal pressure of the voltage-resistant insulating cylinder 1 increases rapidly.

However, in this embodiment, since the insulating filler 15 is made of a rubber-like elastic body with low spring hardness, the insulating filler 15 is damaged by the high-pressure gas.
is deformed toward the pressure relief hole 1a, the space in which the high-pressure gas exists is temporarily expanded, the gas pressure applied to the pressure-resistant insulating cylinder 1 is reduced, and the high-pressure gas is temporarily contained therein. After that, voltage proof insulation with low mechanical strength l! ? il pressure relief hole 1
Insulating filler 15 and insulating jacket 13 are ruptured near the center of point a, and high-pressure gas is released to the outside. Therefore, the voltage-resistant insulating cylinder 1 is not destroyed,
It is possible to reliably prevent the current limiting element 7 from being damaged or scattered.

Further, in the lightning arrester of this embodiment, the insulating filler 15
Trihydrated alumina or 20 to 50% by weight of rubber elastic body
When the insulating filler 15 is thermally decomposed and gasified by the high heat or high-temperature arc, even if a carbonized pyrolysis product is generated without being completely gasified, the generated carbon is It is oxidized and reduced by the catalytic action of trihydrated alumina, and a water vapor flow is generated by the release of crystallized water, and the remaining produced carbon is also discharged from the inside of the lightning arrester to the outside by the water vapor flow. Therefore, by forming a conductive path based on the generated carbon, it is possible to prevent the risk of not being able to interrupt the following flow.

Note that the present invention is not limited to the configuration of the above embodiment, and for example, the insulating jacket 13, the insulating sealing body 14, and the insulating filler 15 are made of a material having a spring hardness of 70Hs (JI
It is also possible to change the structure of each part arbitrarily and embody it without departing from the spirit of the invention, such as by integrally forming it from a rubber elastic body having the same hardness as SA).

[Effect of the invention] Since this invention is configured as explained above,
It has the following effects.

The insulating filler contained in the gap between the voltage-proof insulating cylinder and the current-limiting element has a spring hardness of 75Hs (JIS A).
By constructing the following rubber-like elastic material, an unexpectedly large lightning surge current is applied to the current limiting element, and the high-temperature arc generated at that time causes the insulating filler to thermally decompose and gasify, causing the pressure-resistant insulation tube to Even if the internal pressure of the current limiting element suddenly increases, the voltage-resistant insulating cylinder will not be destroyed, and the risk of the current limiting element being damaged or scattered can be reliably prevented.

Furthermore, by using a rubber-like elastic body of the insulating filler that contains hydrated alumina in a weight ratio of 20 to 50%, the insulating filler is free from heat generated when the insulating filler is thermally decomposed by the high-temperature arc. The carbonized pyrolysis product does not remain as it is, and the formation of a conductive path by the pyrolysis product reliably prevents the risk of inability to interrupt subsequent flow.

[Brief explanation of the drawing]

Fig. 1 is a half-sectional view showing an embodiment of a lightning arrester embodying the present invention, Fig. 2 is a partial perspective view of a voltage-resistant insulating tube, and Fig. 3 is a sectional view taken along line A-A in Fig. 1. be. DESCRIPTION OF SYMBOLS 1... Voltage-proof insulation tube, 1a... Pressure relief hole, 2... Electrode fitting on the grounding side, 4... Electrode fitting on the power supply side, 7... Current-limiting element, 13... Insulation Mantle body, 15...insulating filling material. Patent applicant Nippon Insulator Co., Ltd. Agent
Patent Attorney On 1) Hironobu Figure 1

Claims (2)

[Claims] 1. The electrode fittings (2, 4) on the grounding side and the energizing side are fitted and fixed to both ends of the voltage-resistant insulating tube (1) having a pressure relief hole (1a), and the inner parts are fitted inside the voltage-proof insulating tube (1). A current-limiting element with nonlinear voltage-current characteristics (
7), and both the electrode fittings (2, 4) and the current limiting element (
7) and electrically connect both ends of the voltage insulating cylinder (1).
), the outer periphery of which is covered with an insulating mantle (13), and an insulating filler (15) is accommodated in the gap, the insulating filler (15) having a spring hardness of 75Hs.
(JIS A) A lightning arrester characterized by comprising the following rubber-like elastic body. 2. The rubber-like elastic body contains trihydrated alumina in a weight ratio of 2
The lightning arrester according to claim 1, characterized in that it contains 0 to 50%.