JP2515318B2 - Lightning arrester - Google Patents

Description

【発明の詳細な説明】 発明の目的 （産業上の利用分野） 本発明は送電線に雷撃によるサージ電流が印加された
とき、それを速やかに大地に放電するとともに、その後
生じる続流を遮断し地絡事故を防止して再送電を可能に
する懸垂碍子型の避雷碍子に関するものである。DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) When a surge current due to lightning is applied to a transmission line, the present invention promptly discharges the surge current to the ground and shuts off the follow-up current generated thereafter. The present invention relates to a suspension insulator type lightning protection insulator that prevents a ground fault and enables re-power transmission.

（従来の技術） 従来、雷，開閉サージを吸収し送電線地絡事故を防止
するために送電線路に避雷器を導入することが考えられ
ていた。しかし、単に避雷機能のみを持つ避雷器を送電
線路に取付けることは送電線鉄塔構造及び碍子装置等が
複雑になり好ましくない。このため、従来の碍子の絶縁
・電線支持機能と避雷器の避雷機能を兼ね備えた懸垂碍
子型の避雷碍子が提案されている。この避雷碍子とし
て、本願出願人はキャップ金具とピン金具を具備する碍
子本体に一体形成した平面円形状の笠部に取付筒体を貫
通固定し、その内部に電圧−電流特性が非直線性の限流
素子を収容するとともに、前記取付筒体の上下両端部に
キャップ状の上部電極及び下部電極を嵌合固定し、上部
電極をリード線を介して前記キャップ金具に接続し、下
部電極を同じくリード線を介して前記ピン金具に接続し
たものを提案している。(Prior Art) Conventionally, it has been considered to introduce a lightning arrester into a transmission line in order to absorb lightning and switching surges and prevent a ground fault in the transmission line. However, it is not preferable to attach a lightning arrester having only a lightning protection function to the transmission line because the transmission line tower structure and the insulator device are complicated. Therefore, there has been proposed a suspension insulator type lightning arrestor having both the insulation / electric wire supporting function of the conventional insulator and the lightning arrester function of the lightning arrester. As this lightning protection insulator, the applicant of the present application has a mounting cylindrical body penetratingly fixed to a flat circular cap portion integrally formed with an insulator main body equipped with a cap fitting and a pin fitting, and the voltage-current characteristic of which is non-linear. While accommodating the current limiting element, a cap-shaped upper electrode and a lower electrode are fitted and fixed to both upper and lower ends of the mounting cylinder, and the upper electrode is connected to the cap fitting through a lead wire, and the lower electrode is also the same. It has been proposed to connect to the pin fitting through a lead wire.

（発明が解決しようとする問題点） ところが、上記懸垂碍子型の避雷碍子では、金属製の
上部電極、下部電極及びリード線がいづれも導体である
ため、笠部の沿面絶縁距離がそれだけ減少する。このた
め、限流素子と対応する部分の笠部の沿面絶縁距離を所
定値確保するように笠部の外径を設定する必要があり、
限流素子と対応しない笠部は沿面絶縁距離が必要以上に
大きくなるばかりでなく、笠部の重量が増大し、避雷碍
子が大型化し、製造コストが大幅にアップするという問
題があった。(Problems to be solved by the invention) However, in the above-mentioned suspended insulator type lightning arrestor, since the metal upper electrode, the lower electrode and the lead wire are conductors, the creepage insulation distance of the cap portion is reduced accordingly. . Therefore, it is necessary to set the outer diameter of the cap portion so as to secure a predetermined value for the creepage insulation distance of the cap portion of the portion corresponding to the current limiting element,
The cap portion that does not correspond to the current limiting device has a problem that not only the creepage insulation distance becomes unnecessarily long, but also the weight of the cap portion increases, the lightning protection insulator becomes large, and the manufacturing cost greatly increases.

発明の構成 （問題点を解決するための手段） 第一発明は前記問題点を解決するため、碍子本体の笠
部下面に複数の同心状をなすひだ部を環状に形成し、同
笠部の中央上部に形成した有蓋筒状の頭部にキャップ金
具を被冠固定し、頭部の内側にはピン金具を嵌入固定
し、前記笠部には貫通穴を設け、同貫通穴には電圧−電
流特性が非直線性の限流素子を嵌入し、同限流素子の上
下両端部には上部電極と下部電極を設け、限流素子と対
応する笠部及びひだ部の形状をその半径方向外方へ膨出
し、キャップ金具からピン金具に至る、すなわち、キャ
ップ金具とピン金具で表される両電極間を結ぶ笠部の沿
面絶縁距離が全周にわたってほぼ同一になるように構成
している。Configuration of the Invention (Means for Solving the Problems) In order to solve the above problems, the first invention forms a plurality of concentric folds in an annular shape on the lower surface of the cap portion of the insulator main body. A cap metal fitting is captively fixed to a capped cylindrical head formed in the upper center part, a pin metal fitting is fitted and fixed inside the head, a through hole is provided in the cap portion, and a voltage is applied to the through hole. A current limiting element with a non-linear current characteristic is inserted, and upper and lower electrodes are provided at the upper and lower ends of the current limiting element.The shape of the cap and fold corresponding to the current limiting element is outside the radial direction. It is configured to bulge in one direction and reach from the cap fitting to the pin fitting, that is, the creepage insulation distance of the cap portion connecting both electrodes represented by the cap fitting and the pin fitting is substantially the same over the entire circumference.

第二発明は前記問題点を解決するため、第一発明の構
成に加えて、前記限流素子と対応する複数の前記ひだ部
を一つおきに他の部分よりも下方へ延出するという構成
を採っている。In order to solve the above problems, the second invention is configured such that, in addition to the configuration of the first invention, every other one of the plurality of pleats corresponding to the current limiting element extends below other portions. Is taking.

（作用） 第一発明は前述した構成を採ったので、限流素子と対
応しない笠部の径が必要最小限になり笠部の重量が軽減
される。(Operation) Since the first aspect of the invention has the above-described configuration, the diameter of the cap portion that does not correspond to the current limiting element is minimized and the weight of the cap portion is reduced.

又、第二発明は笠部の重量が軽減されるとともに、限
流素子と対応する笠部及びひだ部の半径方向の膨出量を
小さくして小型化を図ることができる。Further, according to the second aspect of the present invention, the weight of the cap portion is reduced, and the bulging amount in the radial direction of the cap portion and the corrugated portion corresponding to the current limiting element can be reduced to achieve miniaturization.

（実施例） 以下、第一発明を具体化した一実施例を第１〜３図に
従って説明する。(Embodiment) An embodiment embodying the first invention will be described below with reference to FIGS.

第３図に示すように、鉄塔（図示しない）に設けられ
た支持アーム１に吊下金具２を介して懸垂碍子型の避雷
碍子３が多数直列に連結垂下され、同避雷碍子３の最下
端には吊下金具４を介して送電線Ｌが支持されている。As shown in FIG. 3, a large number of suspension insulator type lightning protection insulators 3 are connected in series to a support arm 1 provided on a steel tower (not shown) via suspension metal fittings 2, and the lowermost end of the lightning protection insulator 3 is suspended. The transmission line L is supported by the hanging metal fitting 4.

第２図に示すように、避雷碍子３を構成する碍子本体
５は笠部5aと、同笠部5aの内側面に円環状に、かつ同心
状に形成された複数のひだ部5bと、さらに、前記笠部5a
の中央上部に一体形成された有蓋円筒状の頭部5cとによ
り一体成型されている。又、同頭部5cの外周にはセメン
ト６によりキャップ金具７が被冠固定され、同金具７に
は係合凹部7aが形成され、直上の避雷碍子３のピン金具
８を係合し得るようにしている。ピン金具８の上部は前
記頭部5cの内部にセメント６により固定され、下端は直
下の避雷碍子３の前記キャップ金具７の嵌合凹部7aに係
合されている。このようにして複数の避雷碍子３が直列
に連結されている。As shown in FIG. 2, the insulator main body 5 that constitutes the lightning protection insulator 3 includes a cap portion 5a, a plurality of pleated portions 5b formed in an annular shape and concentrically on the inner surface of the cap portion 5a, and , Said Kasabbe 5a
Is integrally molded with a cylindrical head portion 5c with a lid integrally formed in the upper center part of the. Further, a cap metal fitting 7 is capped and fixed to the outer periphery of the head 5c by cement 6, and an engaging concave portion 7a is formed in the metal fitting 7 so that the pin metal fitting 8 of the lightning protection insulator 3 directly above can be engaged. I have to. The upper portion of the pin fitting 8 is fixed inside the head portion 5c with cement 6, and the lower end is engaged with the fitting recess 7a of the cap fitting 7 of the lightning protection insulator 3 directly below. In this way, the plurality of lightning protection insulators 3 are connected in series.

前記笠部5aには第１図及び第２図に示すように円筒状
をなす複数（本実施例では３箇所）の取付筒部5dが等間
隔に、かつピン金具８と平行状に同笠部5aを貫通するよ
うに一体に形成されている。前記各取付筒部5dの内周
面、つまり貫通穴5eには酸化亜鉛（ZnO）を主材とした
続流遮断特性に優れた電圧−電流特性が非直線性の円柱
状をなす複数（この実施例では２個）の限流素子９が直
列に嵌入され、貫通穴5eと限流素子９の外周面との間に
は、シリコンゴム等の弾性絶縁材10が介在接着されてい
る。なお、この弾性絶縁材10に代えて低融点ガラスを充
填接着してもよい。As shown in FIG. 1 and FIG. 2, a plurality of (3 in this embodiment) cylindrical mounting portions 5d are attached to the cap portion 5a at equal intervals and in parallel with the pin fitting 8. It is integrally formed so as to penetrate the portion 5a. In the inner peripheral surface of each of the mounting cylinders 5d, that is, in the through holes 5e, a plurality of non-linear cylindrical columns having non-linear voltage-current characteristics, which are mainly made of zinc oxide (ZnO) and have excellent follow-current blocking characteristics, are provided. In the embodiment, two current limiting elements 9 are fitted in series, and an elastic insulating material 10 such as silicone rubber is interposed and bonded between the through hole 5e and the outer peripheral surface of the current limiting element 9. Instead of the elastic insulating material 10, low melting point glass may be filled and bonded.

前記限流素子９の上下両端面には、銅の薄板（例えば
0.5〜1mm）よりなる補助電極11が接着固定され、同補助
電極11の外周部及び取付筒部5dの上下両端面には導電性
を有するガラス・セラミック接着用金属はんだ（旭碍子
株式会社製の商品名、セラソルザ）12が弾性絶縁材10及
び補助電極11の外周部を封着するように接着固定されて
いる。このガラス・セラミック接着用金属はんだ12は、
普通はんだPb−Sn合金を主成分とし、これにZn,Sbを添
加した四元系合金である。このはんだ12はガラス・セラ
ミックの表面に特殊な処理を施すことなく、直接強固に
接着できる特性をもつ。接着に際しては、超音波を用い
るのが有効で、超音波はんだこてディップ槽、超音波盛
上げ浴が適用でき、はんだ付け作業は、60KHz、15Wの超
音波発振器を用いたはんだ鏝で、１〜３秒で信頼性の高
い接合ができる。なお、このはんだ12は前記補助電極11
の全面に施してもよい。On both upper and lower end surfaces of the current limiting element 9, thin copper plates (for example,
0.5 to 1 mm) of the auxiliary electrode 11 is adhesively fixed, and the outer peripheral portion of the auxiliary electrode 11 and the upper and lower end surfaces of the mounting tubular portion 5d have conductive glass-ceramic bonding metal solder (made by Asahi Insulator Co., Ltd. A product name, Cerasolzer 12 is bonded and fixed so as to seal the outer peripheral portions of the elastic insulating material 10 and the auxiliary electrode 11. This glass / ceramic bonding metal solder 12
It is a quaternary alloy containing normal solder Pb-Sn alloy as a main component and Zn, Sb added thereto. This solder 12 has the property that it can be directly and firmly bonded to the surface of glass / ceramic without any special treatment. For bonding, it is effective to use ultrasonic waves, ultrasonic soldering iron dip bath, ultrasonic rising bath can be applied, soldering work is done with a soldering iron using an ultrasonic oscillator of 60 KHz, 15 W, Highly reliable bonding can be achieved in 3 seconds. The solder 12 is the auxiliary electrode 11
May be applied to the entire surface of.

前記はんだ12により取付筒部5d内の気密性を向上し、
前記限流素子９の湿気による劣化を防止するようにして
いる。前記取付筒部5dには、前記補助電極11及びセラミ
ック接着用金属はんだ12を覆うようにキャップ状の上部
電極13及び下部電極14が嵌合され、その外周部において
取付筒部5dにカシメ付けされている。By the solder 12 to improve the airtightness in the mounting tube portion 5d,
The current limiting element 9 is prevented from being deteriorated by moisture. A cap-shaped upper electrode 13 and a lower electrode 14 are fitted to the mounting cylinder portion 5d so as to cover the auxiliary electrode 11 and the ceramic bonding metal solder 12, and the mounting cylinder portion 5d is caulked at the outer peripheral portion thereof. ing.

前記補助電極11と前記両電極13,14の間には、平面ド
ーナッツ板状の導電性を有する皿バネ15が介在され、限
流素子９と上部電極13及び下部電極14との電気的接続を
行う。Between the auxiliary electrode 11 and the both electrodes 13 and 14, a flat donut plate-shaped conductive disc spring 15 is interposed to electrically connect the current limiting element 9 to the upper electrode 13 and the lower electrode 14. To do.

前記下部電極13及び下部電極14の内側、つまり皿バネ
15の収容空間には、前記弾性絶縁材10が充填されてい
る。又、前記取付筒部5dと両電極13,14との間隙に形成
された小間隙ｇにも弾性絶縁材10が充填され、セラミッ
ク接着用金属はんだ12と両電極13,14との気密性をもた
せている。又、両電極13,14のカシメ部にも前述したセ
ラミック接着用金属はんだ12を充填接着している。Inside the lower electrode 13 and the lower electrode 14, that is, a disc spring
The accommodating space of 15 is filled with the elastic insulating material 10. Further, the elastic insulating material 10 is also filled in the small gap g formed in the gap between the mounting cylinder portion 5d and the electrodes 13 and 14 so that the airtightness between the ceramic bonding metal solder 12 and the electrodes 13 and 14 is improved. I am holding it. Further, the metal solder 12 for ceramic bonding described above is also filled and bonded to the crimped portions of both electrodes 13 and 14.

前記上部電極13の上面及び下部電極14の下面にはそれ
ぞれはんだ16付け、あるいは圧着などによりリード線1
7,18の一端が接着固定され、上部のリード線17の他端は
前記キャップ金具７に接続され、下部のリード線18の他
端は前記ピン金具８に接続されている。The lead wire 1 is attached to the upper surface of the upper electrode 13 and the lower surface of the lower electrode 14 by soldering 16 or pressure bonding, respectively.
One end of 7, 18 is adhesively fixed, the other end of the upper lead wire 17 is connected to the cap fitting 7, and the other end of the lower lead wire 18 is connected to the pin fitting 8.

第１図に示すように、前記限流素子９と対応する前記
笠部5a及びひだ部5bを同笠部5aの径方向へ各ひだ部5bが
等間隔になるように膨出させて、笠部5aのどの部位もキ
ャップ金具７からピン金具８までの沿面絶縁距離がほぼ
同一になるようにしている。すなわち、上部電極13、下
部電極14及びリード線17,18により笠部5aの沿面絶縁距
離が低下した分だけ、笠部5a及びひだ部5bを膨出してい
る。As shown in FIG. 1, the cap portion 5a and the corrugated portion 5b corresponding to the current limiting element 9 are bulged in the radial direction of the cap portion 5a so that the corrugated portions 5b are arranged at equal intervals. The creepage insulation distance from the cap metal fitting 7 to the pin metal fitting 8 is made to be almost the same in any part of the portion 5a. That is, the cap portion 5a and the corrugated portion 5b are bulged by the amount by which the creeping insulation distance of the cap portion 5a is reduced by the upper electrode 13, the lower electrode 14, and the lead wires 17 and 18.

次に、以上のように構成された避雷碍子についてその
作用を説明する。Next, the operation of the lightning protection insulator configured as described above will be described.

送電線Ｌに雷サージの過大電圧が印加されると、この
ときの電流は吊下金具４を経て最下側の避雷碍子３のピ
ン金具８へ流れ、リード線18→下部電極14→皿バネ15→
セラミック接着用金属はんだ12→限流素子９→セラミッ
ク接着用金属はんだ12→皿バネ15→上部電極13→リード
線17→キャップ金具７へと伝達される。その後、同キャ
ップ金具７から、直上の避雷碍子３のピン金具８へ伝達
される。同様に複数直列に連結された避雷碍子３に伝達
され、最上端の避雷碍子３のキャップ金具７から吊下金
具２、及び支持アーム１を経て大地へアースされる。When an excessive voltage of a lightning surge is applied to the power transmission line L, the current at this time flows through the hanging metal fitting 4 to the pin metal fitting 8 of the lightning protection insulator 3 on the lowermost side, and the lead wire 18 → the lower electrode 14 → the disc spring. 15 →
It is transmitted to the ceramic bonding metal solder 12 → current limiting element 9 → ceramic bonding metal solder 12 → disc spring 15 → upper electrode 13 → lead wire 17 → cap fitting 7. Then, it is transmitted from the cap metal fitting 7 to the pin metal fitting 8 of the lightning protection insulator 3 directly above. Similarly, it is transmitted to a plurality of lightning protection insulators 3 connected in series, and is grounded from the cap fitting 7 of the uppermost lightning protection insulator 3 through the hanging fitting 2 and the support arm 1 to the ground.

このとき、碍子本体５に内蔵された限流素子９はその
特性により速やかに抵抗値を減じて雷サージによる大電
流を放電させる。又、前記雷サージに継続する続流に対
しては限流素子９は直ちに抵抗値を復元して絶縁を回復
するので、続流放電は抑制遮断されて電線路は正常に復
帰する。At this time, the current limiting element 9 built in the insulator main body 5 quickly reduces the resistance value due to its characteristics and discharges a large current due to a lightning surge. Further, the current limiting element 9 immediately restores the resistance value and restores the insulation with respect to the continuous current continuing to the lightning surge, so that the continuous current discharge is suppressed and interrupted and the electric line is normally restored.

さて、本発明では限流素子９と対応する笠部5a及びひ
だ部5bを部分的に外方へ膨出することにより、笠部5aの
どの部位もキャップ金具７からピン金具８までの沿面絶
縁距離がほぼ同じとなるようにしたので、笠部5aに必要
以上に沿面絶縁距離が大きくなる部位をなくして、笠部
5aの重量を軽減し、材料費を節約することができる。ち
なみに、500KV用の33トン懸垂碍子で従来どおりに笠部5
aの形状を円形にすると、約27kgであるが、本発明では2
2kgとなり、一個の懸垂碍子につき約5kgの軽減となる。Now, in the present invention, by partially bulging the cap portion 5a and the corrugated portion 5b corresponding to the current limiting element 9 to the outside, any part of the cap portion 5a is subjected to creepage insulation from the cap metal fitting 7 to the pin metal fitting 8. Since the distances are set to be almost the same, there is no part of the cap portion 5a where the creepage insulation distance becomes larger than necessary,
The weight of 5a can be reduced and the material cost can be saved. By the way, with a 33 ton suspension insulator for 500 KV, the Kasae 5
When the shape of a is circular, it weighs about 27 kg.
It will be 2kg, which is about 5kg reduction per suspension insulator.

次に、第４図により第二発明の実施例を説明する。 Next, an embodiment of the second invention will be described with reference to FIG.

この実施例は前記第一発明の実施例に加えて、限流素
子９と対応するひだ部5bを、他の部位のひだ部5bよりも
下方へ長く延ばしている。従って、そのひだ部5bが下方
へ延びた分だけ笠部5aの外方への膨出量を小さくするこ
とができ、最大笠径を小さくして避雷碍子の小型化を図
ることができる。In this embodiment, in addition to the embodiment of the first invention, the folds 5b corresponding to the current limiting element 9 are extended longer than the folds 5b of other parts. Therefore, the amount of outward expansion of the cap portion 5a can be reduced by the amount by which the fold portion 5b extends downward, and the maximum cap diameter can be reduced to reduce the size of the lightning protection insulator.

なお、本発明は前記実施例に限定されるものではな
く、次のように具体化してもよい。The present invention is not limited to the above embodiment, but may be embodied as follows.

（１）第５図に示すように３個又は４個以上（図示略）
の限流素子９を等角度に配置し、各限流素子９と対応す
る笠部5a及びひだ部5bを膨出すること。(1) 3 or 4 or more (not shown) as shown in FIG.
The current limiting elements 9 are arranged at equal angles, and the cap portion 5a and the fold portion 5b corresponding to each current limiting element 9 are bulged.

（２）前記取付筒部5dを別体で形成したり、笠部5aの上
面と面一になるようにしたりすること。(2) The mounting tube portion 5d is formed as a separate body or is flush with the upper surface of the cap portion 5a.

（４）ガラス・セラミック接着用金属はんだ12を厚肉に
して、これを上部電極及び下部電極とし、ここにリード
線17,18を接続すること。(4) Thicken the glass-ceramic bonding metal solder 12, use it as the upper electrode and the lower electrode, and connect the lead wires 17 and 18 thereto.

発明の効果 以上詳述したように、第一発明は笠部の重量を小さく
して製造コストを低減することができる効果がある。Effects of the Invention As described in detail above, the first invention has an effect that the weight of the cap portion can be reduced to reduce the manufacturing cost.

又、第二発明は第一発明の効果に加えて、笠部の最大
外径をさらに小さくして、避雷碍子の小型化を図ること
ができる効果がある。Further, in addition to the effect of the first invention, the second invention has an effect that the maximum outer diameter of the cap portion can be further reduced and the lightning protection insulator can be miniaturized.

【図面の簡単な説明】[Brief description of drawings]

第１図〜第３図は第一発明の実施例を示し、第１図は第
２図のＡ−Ａ線断面図、第２図は避雷碍子の要部を示す
部分縦断面図、第３図は避雷碍子の使用状態を示す正面
図、第４図は第二発明の実施例を示す断面図、第５図は
本発明の別例を示す要部の断面図である。 ３……避雷碍子、５……碍子本体、5a……笠部、5b……
ひだ部、5c……頭部、5d……取付筒部、5e……貫通穴、
７……キャップ金具、８……ピン金具、９……限流素
子、13,14……上部，下部電極、17,18……リード線。1 to 3 show an embodiment of the first invention, FIG. 1 is a sectional view taken along the line AA of FIG. 2, and FIG. 2 is a partial vertical sectional view showing a main part of a lightning arrester. FIG. 4 is a front view showing a usage state of the lightning arrester, FIG. 4 is a cross-sectional view showing an embodiment of the second invention, and FIG. 5 is a cross-sectional view of a main part showing another example of the present invention. 3 ... Lightning protection insulator, 5 ... Insulator body, 5a ... Kasabe, 5b ...
Folds, 5c ... Head, 5d ... Mounting cylinder, 5e ... Through hole,
7 ... Cap metal fitting, 8 ... Pin metal fitting, 9 ... Current limiting element, 13,14 ... Upper and lower electrodes, 17,18 ... Lead wire.

Claims (2)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】碍子本体（５）の笠部（5a）下面に複数の
同心状をなすひだ部（5b）を環状に形成し、同笠部（5
a）の中央上部に形成した有蓋筒状の頭部（5c）にキャ
ップ金具（７）を被冠固定し、頭部（5c）の内側にはピ
ン金具（８）を嵌入固定し、前記笠部（5a）には貫通穴
（5e）を設け、同貫通穴（5e）には電圧−電流特性が非
直線性の限流素子（９）を嵌入し、同限流素子（９）の
上下両端部には上部電極と下部電極を設け、限流素子
（９）と対応する笠部（5a）及びひだ部（5b）の形状を
その半径方向外方へ膨出し、キャップ金具（７）からピ
ン金具（８）に至る笠部（5a）の沿面絶縁距離が全周に
わたってほぼ同一になるように構成したことを特徴とす
る避雷碍子。1. A plurality of concentric folds (5b) are formed in an annular shape on the lower surface of the cap portion (5a) of the insulator body (5), and the cap portion (5) is formed.
The cap metal fitting (7) is capped and fixed to the head (5c) having a cylindrical shape with a lid formed in the central upper part of a), and the pin metal fitting (8) is fitted and fixed inside the head (5c), A through hole (5e) is provided in the portion (5a), and a current limiting element (9) having a non-linear voltage-current characteristic is fitted in the through hole (5e) so that the current limiting element (9) is placed above and below the current limiting element (9). An upper electrode and a lower electrode are provided at both ends, and the shape of the cap portion (5a) and the corrugated portion (5b) corresponding to the current limiting element (9) bulges outward in the radial direction, and the cap metal fitting (7) The lightning protection insulator characterized in that the insulation distance of the surface of the cap portion (5a) reaching the pin fitting (8) is substantially the same over the entire circumference. 【請求項２】碍子本体（５）の笠部（5a）下面に複数の
同心状をなすひだ部（5b）を環状に形成し、同笠部（5
a）の中央上部に形成した有蓋筒状の頭部（5c）にキャ
ップ金具（７）を被冠固定し、頭部（5c）の内側にはピ
ン金具（８）を嵌入固定し、前記笠部（5a）には貫通穴
（5e）を設け、同貫通穴（5e）には電圧−電流特性が非
直線性の限流素子（９）を嵌入し、同限流素子（９）の
上下両端部には上部電極と下部電極を設け、限流素子
（９）と対応する笠部（5a）及びひだ部（5b）の形状を
その半径方向外方へ膨出し、キャップ金具（７）からピ
ン金具（８）に至る笠部（5a）の沿面絶縁距離が全周に
わたってほぼ同一になるように構成し、さらに前記限流
素子（９）と対応する複数の前記ひだ部（5b）を一つお
きに他の部分よりも下方へ延出したことを特徴とする避
雷碍子。2. A plurality of concentric folds (5b) are formed in an annular shape on the lower surface of the cap portion (5a) of the insulator body (5), and the cap portion (5a) is formed.
The cap metal fitting (7) is capped and fixed to the head (5c) having a cylindrical shape with a lid formed in the central upper part of a), and the pin metal fitting (8) is fitted and fixed inside the head (5c), A through hole (5e) is provided in the portion (5a), and a current limiting element (9) having a non-linear voltage-current characteristic is fitted in the through hole (5e) so that the current limiting element (9) is placed above and below. An upper electrode and a lower electrode are provided at both ends, and the shape of the cap portion (5a) and the corrugated portion (5b) corresponding to the current limiting element (9) bulges outward in the radial direction, and the cap metal fitting (7) The cap portion (5a) reaching the pin fitting (8) is configured so that the creeping insulation distance is substantially the same over the entire circumference, and further, the plurality of pleats (5b) corresponding to the current limiting element (9) are connected to each other. Lightning arrester characterized in that it extends downwards from the other parts at every other interval.