JP2008178274A - Arrester and arrester attachment section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure surface pressure between the inner circumference of a receiving opening in a fixing bushing and the outer circumference at a tip of an insulating cylinder, and to prevent dielectric breakdowns at an interface. <P>SOLUTION: A conductor 2 in an arrester includes a plug head 21, plugged in a conductor insertion hole 94 in a high-voltage shield 91 outwardly protruding from the tip 11 of the insulating cylinder 1; a rod drawer 22 consecutively installed at the back end of the head 21, and mounted to an insertion section at the tip 11 of the insulating cylinder 1. A tapered outer face 22a is provided on the outer circumference of the drawer 22, and extended sequentially, smoothly and radially toward the back end of the drawer 22, at a tapered angle of 2-4°, desirably at 3°. The tapered angle of the drawer 22 in the conductor 2 is substantially equal to the tapered angle at the tip 11 of the insulating cylinder 1 and to the taper angle of the receiving opening 92 in the fixing bushing 9. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an arrester and a mounting portion of an arrester, and in particular, an arrester capable of ensuring a surface pressure between an inner peripheral surface of a receiving port of a fixed bushing and an outer peripheral surface of a distal end portion of an insulating cylinder and preventing dielectric breakdown at the interface. And the mounting part of the arrester.

  In general, gas insulated switchgear installed in power plants, substations, etc. are provided with arresters to protect electrical equipment such as switchgears and transformers from abnormal voltages entering from the track during lightning strikes. Yes.

  Conventionally, as this type of arrester, as shown in FIG. 5, a fixed bushing 120 is airtightly attached to the inner wall of the device case 110, and an insulating cylinder 140 in which the arrester element laminate 130 is accommodated in the receiving port 120 a of the fixed bushing 120. There is known one that is provided with a front end portion 140a (for example, Patent Document 1).

  In the arrester having such a configuration, each component of the arrester is made of a solid insulator, and therefore, an interface between the inner peripheral surface of the receiving port 120a of the fixed bushing 120 and the outer peripheral surface of the distal end portion 140a of the insulating tube 140. It is necessary to apply a predetermined surface pressure.

  Therefore, for example, as shown in FIG. 6, the insulating cylinder 220 and the ground electrode 230 that contain the arrester element stack 210 are surrounded by a metal case 240, and a spring 250 disposed on the rear end side of the ground electrode 230 is arranged. An arrester has been devised in which a pressing force is applied to the arrester element stack 210 in the direction of the tip by a spring force. In the figure, reference numeral 260 denotes a device case, and 270 denotes a fixed bushing.

  However, in the arrester having such a configuration, a predetermined surface pressure can be applied to the zinc oxide element 210a constituting the arrester element stack 210, but the inner peripheral surface of the receiving port 270a of the fixed bushing 270 and the insulating cylinder There is a difficulty in that a predetermined surface pressure cannot be applied to the interface between the outer peripheral surface of the front end portion 220a of 220. That is, in the conventional arrester, the conductor 280 disposed at the center of the tip 220a of the insulating cylinder 220 is formed in a straight bar shape, and the interface between the outer peripheral surface of the conductor 280 and the inner peripheral surface of the insulating cylinder 220 is formed. Since the direction is parallel to the direction of the pressing force by the spring 250, when the spring force by the spring 250 is applied to the conductor 280 in this state, the conductor 280 slides in the inner peripheral surface of the insulating cylinder 220. As a result, the spring force by the spring 250 does not act on the tip of the insulating cylinder 220. For this reason, a predetermined surface pressure cannot be applied to the interface between the inner peripheral surface of the receiving port 270a of the fixed bushing 270 and the outer peripheral surface of the distal end portion 220a of the insulating tube 220, and as a result, there is a risk of dielectric breakdown at the interface. there were. In this case, an attempt is made to bond the conductor 280 and the insulating cylinder 220 by providing an adhesive layer on the outer periphery of the conductor 280. However, since the conductor 280 is formed in a straight bar shape, There is a problem that the spring force cannot be effectively applied as the surface pressure.

Japanese Patent Laid-Open No. 1-232681 (FIG. 1)

  The present invention has been made to solve the above-mentioned problems, and ensures a surface pressure between the inner peripheral surface of the receiving port of the fixed bushing and the outer peripheral surface of the tip end portion of the insulating cylinder, and prevents dielectric breakdown at the interface. The purpose of the present invention is to provide an arrester and an arrester mounting portion.

  The arrester according to the first aspect of the present invention includes an insulating cylinder having a conductor at the tip, an arrester element laminate inserted into the insulating cylinder via a high-voltage electrode, and a rear end side of the arrester element laminate. A grounding electrode is provided, and a taper outer surface is provided on the outer periphery of the conductor, and the taper outer surface gradually increases in diameter toward the rear end portion of the conductor at a predetermined taper angle.

  The arrester according to the second aspect of the present invention includes an insulating cylinder having a conductor at the tip, an arrester element stack inserted into the insulating cylinder via a high-voltage electrode, and a rear end side of the arrester element stack. A ground electrode to be disposed; a coiled spring disposed concentrically with the insulating tube on the rear end side of the ground electrode; a metal case surrounding the insulating tube, the ground electrode and the spring; and a rear of the metal case And a sealing member attached to the opening on the end side, and a tapered outer surface is provided on the outer periphery of the conductor, the taper outer surface gradually increasing in diameter toward the rear end of the conductor at a predetermined taper angle. .

  According to a third aspect of the present invention, in the arrester according to the first aspect or the second aspect, the outer periphery of the front end portion of the insulating tube is gradually increased in diameter toward the rear end portion of the insulating tube at a predetermined taper angle. A tapered outer surface is provided.

  According to a fourth aspect of the present invention, in the arrester according to the third aspect, the taper angle of the conductor is substantially equal to the taper angle of the insulating cylinder.

  According to a fifth aspect of the present invention, in the arrester according to any one of the first to fourth aspects, at least one of a side of the conductor facing the high voltage electrode and a side of the high voltage electrode facing the conductor In addition, a storage hole for storing the spring is provided.

  According to a sixth aspect of the present invention, in the arrester according to any one of the first to fifth aspects, a plug is attached to the outer periphery of the tip of the conductor.

  The mounting portion of the arrester according to the seventh aspect of the present invention includes an equipment case that houses electrical equipment and has a through hole in a part thereof, a fixed bushing that is disposed inside the equipment case, and first to thirteenth aspects. And a receiving port having a taper inner surface that sequentially decreases in diameter toward the front end of the fixed bushing at a predetermined taper angle. The tip of the arrester is mounted inside the fixed bushing.

  According to an eighth aspect of the present invention, in the mounting portion of the arrester according to the seventh aspect, the taper angle of the conductor is substantially equal to the taper angle of the receiving port.

  According to the arrester and the mounting portion of the arrester of the first to eighth aspects of the present invention, the outer periphery of the conductor is provided with a tapered outer surface that gradually increases in diameter toward the rear end of the conductor at a predetermined taper angle. Therefore, by applying a pressing force to the conductor in the direction of the distal end of the fixed bushing, the axial pressing force against the conductor is passed through the tapered outer surface of the conductor and the inner peripheral surface of the fixed bushing receiving port and the insulating cylinder Can be applied in a direction substantially perpendicular to the mating surface (interface) with the outer surface of the taper at the tip, and by applying effective axial pressure as the surface pressure, dielectric breakdown at the interface can be achieved. Can be prevented.

Hereinafter, preferred embodiments to which the arrester of the present invention is applied will be described with reference to the drawings. In the following description, the “tip” of the insulating cylinder, conductor, arrester element laminate, ground electrode, spring, metal case, and fixed bushing are respectively the insulating cylinder, conductor, arrester element laminate, ground electrode, spring. The end of the metal case and the fixed bushing on the high-pressure side corresponds to the left direction in the figure. The “rear end” of the insulating cylinder, conductor, arrester element laminate, ground electrode, spring, metal case, and fixed bushing are the insulating cylinder, conductor, arrester element laminate, ground electrode, spring, metal case and The end of the fixed bushing on the low pressure side, which corresponds to the right direction in the figure.
[Example 1]
1 is a partial cross-sectional view showing an example of the arrester of the present invention, FIG. 2 is a partial cross-sectional view in which the tip of the arrester of the present invention is enlarged, and FIG. 3 is an enlarged view of the rear end of the arrester of the present invention. FIG.

  In FIG. 1, a 22 kV class arrester according to the present invention includes an insulating cylinder 1 made of a rubber-like elastic body such as silicone rubber. An aluminum rod or the like is provided at the center of the distal end (high pressure side) 11 of the insulating cylinder 1. A conductor 2 is provided. Further, a spindle-shaped large-diameter portion 12 is provided at the outer periphery of the substantially central portion of the insulating cylinder 1, and the outer periphery of the distal end portion of the insulating cylinder 1 has a taper angle of 2 to 4 °, preferably about 3 °, after the insulating cylinder 1 Tapered outer surfaces 13 that gradually increase in diameter toward the end direction are respectively provided, and bell mouth portions 14 are provided at portions where the tapered outer surface 13 and the large diameter portion 12 are connected. Further, a portion of the insulating cylinder 1 on the rear end side (low pressure side) 15 (hereinafter referred to as “small diameter portion”) 15 from the large diameter portion 12 has a high pressure which will be described later across the position corresponding to the large diameter portion 12 from the rear end surface. An insertion portion 16 for accommodating the electrode 3, the arrester element stack 4 and the ground electrode 5 is provided. A conductive paint is applied to the outer surface of the bell mouth portion 14 across the rear end of the small diameter portion 15 of the insulating cylinder 1.

  As shown in FIG. 2, the conductor 2 protrudes outward from the distal end portion 11 of the insulating cylinder 1 and is plug-in connected to a conductor insertion hole 94 of a high-voltage shield body 91 described later, A rod-like lead portion 22 is provided which is connected to the rear end portion side of the head portion 21 and is mounted in the insertion portion 17 on the distal end portion 11 side of the insulating cylinder 1. An annular groove 23 is provided on the outer periphery of the head 21, and a tape-like conductor connector (multi-contact) 24 is fitted in the groove 23 along the circumferential direction of the groove 23. Yes. Further, a tapered outer surface 22a is provided on the outer peripheral portion of the lead-out portion 22 so as to smoothly and gradually increase in diameter toward the rear end portion of the lead-out portion 22 at a taper angle of 2 to 4 °, preferably about 3 °. . Here, the taper angle of the lead portion 22 in the conductor 2 is substantially equal to the taper angle of the tip portion 11 in the insulating tube 1 and the taper angle of the receiving port 92 in the fixed bushing 9 described later.

  The arrester element laminate 4 is formed by laminating a plurality of non-linear resistance elements (hereinafter referred to as “arrestor elements”) 41 mainly composed of disc-shaped zinc oxide. A cylindrical high voltage electrode 3 and a ground electrode 5 made of aluminum or the like are disposed on the front end side (high pressure side) and the rear end side (low pressure side), respectively.

  The high-voltage electrode 3 has an outer diameter substantially the same as the outer diameter of the arrester element 41, and a coiled spring (hereinafter referred to as “high-pressure side spring”), which will be described later, on the side facing the rear end of the lead-out portion 22 of the conductor 2. The storage hole 31 for storing S is provided concentrically with the high-voltage electrode 3.

  As shown in FIG. 3, the ground electrode 5 includes a small-diameter ground electrode 51 having an outer diameter substantially the same as the outer diameter of the arrester element 41, and a metal that is connected to the rear end side of the small-diameter ground electrode 51 and will be described later. A large-diameter ground electrode 52 having an outer diameter substantially the same as the inner diameter of the small-diameter cylindrical portion 62 of the case 6 is provided, and the rear end portion center of the large-diameter ground electrode 52 faces the opening of the metal case 6. A rigid body 53 made of an aluminum rod or the like extending in a projecting manner is provided concentrically with the ground electrode 5.

  Reference numeral 6 denotes a cylindrical metal case surrounding a portion excluding the tip of the insulating cylinder 1, the ground electrode 5, and a spring 8 described later. The metal case 6 has a large-diameter portion 12 of the insulating cylinder 1. A large-diameter cylindrical portion 61 that surrounds, and a small-diameter cylindrical portion 62 that surrounds the small-diameter portion 15 of the insulating cylinder 1, the ground electrode 5, and the spring 8. An annular locking portion 63 that is orthogonal to the axis of the metal case 6 and extends in the center direction of the metal case 6 is provided. Further, an annular protrusion 63 a that is orthogonal to the axis of the metal case 6 and extends in the center direction of the metal case 6 is provided on the inner periphery of the locking portion 63. Furthermore, a funnel-shaped taper 64 is provided on the inner peripheral surface of the connecting portion of the small-diameter cylindrical portion 62 and the large-diameter cylindrical portion 61. The funnel-shaped taper 64 gradually increases in diameter toward the tip portion. The insertion hole 65 is provided from the rear end surface to the front end surface of the large diameter cylindrical portion 61. The bolt insertion holes 65 are provided, for example, so as to be equally arranged along the circumferential direction of the three large-diameter cylindrical portions 61.

  The sealing member 7 includes a circular lid member 71 that is airtightly attached to the inner periphery of the locking portion 63 via the O-ring R1, and the inner periphery of the locking portion 63 that is closer to the tip than the protrusion 63a. A circular pressure release plate 72 is provided, and the lid member 71 and the pressure release plate 72 are formed of an aluminum disc or the like. Here, the lid member 71 is connected to the large-diameter lid member 71a having an outer diameter substantially the same as the inner diameter of the locking portion 63, and the side of the large-diameter lid member 71a facing the ground electrode 5, and is connected to the protrusion 63a. A small-diameter lid member 71b having an outer diameter smaller than the inner diameter. The small-diameter lid member 71b is provided with two screw holes spaced from the end surface side over a part of the large-diameter lid member 71a. ing. Further, the outer diameter of the pressure release plate 72 is substantially the same as the inner diameter of the locking portion 63, and through holes are provided in portions corresponding to the screw holes of the small diameter lid member 71b. The thickness of the pressure release plate 72 is, for example, about 2 mm.

  Reference numeral 8 denotes a coiled spring made of stainless steel or the like, and the spring 8 faces a locking portion 63 of the large-diameter ground electrode 52 (hereinafter referred to as a “grounding electrode locking surface”) 52a. Between the surface (hereinafter referred to as the “locking surface of the metal case”) 63 b facing the locking surface 52 a of the ground electrode as the locking portion 63, it is disposed concentrically with the insulating cylinder 1. In addition, two conductive members 81, 81 made of a copper plate or the like for electrically connecting the ground electrode 5 and the metal case 6 are disposed inside the spring 8 so as to be separated from each other. A large current flows through 81, 81. Note that both end portions of these conductive members 81 are brought into contact with the inner peripheral surface of the small-diameter cylindrical portion 62 of the metal case 6 by folding back to the outside of the spring 8.

  Here, the outer diameter of the spring 8 is approximately the same as or slightly smaller than the large-diameter ground electrode 52, and the inner diameter of the spring 8 is approximately the same as or slightly larger than the inner diameter of the locking portion 63. The outer diameter of the pressure release plate 72 is smaller than the inner diameter of the spring 8 and slightly larger than the inner diameter of the protrusion 63a.

  According to the locking part 63, the pressure release plate 72 and the spring 8 of the metal case 6 having such a configuration, the rear end side of the spring 8 is brought into contact only with the locking surface 63b of the metal case 6, and the pressure release plate 72 The spring force of the spring 8 does not act.

  1 to 3, reference numerals V2 and V3 are bolts, 12a is an annular protrusion for preventing the metal case 6 from being detached, and 61a is an inner periphery of the large-diameter cylindrical portion 61 of the metal case 6 on the tip side. An annular groove 11a is provided, 11a is an annular stopper embedded in the tip 11 of the insulating cylinder 1, Sa is a conductive member made of a copper plate or the like for electrically connecting the conductor 2 and the high voltage electrode 3 and the like. Show.

  Next, a method for assembling the mounting portion of the arrester in the present invention will be described.

  In FIG. 1, first, a fixed bushing 9 made of an epoxy resin mold or the like described below is airtightly attached to the inner wall of a device case C that houses an electric device (not shown).

  A cylindrical high-pressure shield body 91 that is closed at one end is embedded concentrically with the fixed bushing 9 at the center of the front end side (high-pressure side) of the fixed bushing 9, and on the rear end side (low-pressure side) of the fixed bushing 9. Is provided with a receiving port 92 having a tapered inner surface that gradually decreases in diameter toward the distal end portion of the fixed bushing at a taper angle of about 2 to 4 °, preferably about 3 °.

  The front end side of the high-voltage shield body 91 protrudes outward from the closing portion (front end portion) 93 of the fixed bushing 9, and a circular conductor insertion hole 94 for receiving the conductor 2 of the arrester is provided on the rear end side. It has been.

  In the figure, reference numeral 91a denotes a shield provided so as to cover the vicinity of the front end portion of the receiving port 92, and 95 denotes an embedded metal fitting having a screw hole embedded in the rear end portion of the fixed bushing 9. .

The fixed bushing 9 having such a configuration has its rear end abutted against the inner wall side of the device case C via the O-ring R2 and fastened with a bolt (not shown), so that the fixed bushing 9 is airtight on the inner wall side of the device case C. It is attached. The device case C is filled with an insulating gas such as SF ₆ gas.

  On the other hand, the arrester is assembled and fixed as follows.

  First, the pressure release plate 72 is disposed from the inside of the small diameter cylindrical portion 62 on the inner periphery of the locking portion 63 constituting the metal case 6 and the lid member 71 having the O ring R1 disposed from the outside of the small diameter cylindrical portion 62 is disposed. Then, both are fastened and fixed with bolts V1 and V1. In parallel with this, the high voltage electrode 3, the arrester element laminate 4 and the ground electrode 5 are arranged as shown in FIG. The high-voltage electrode 3, the arrester element laminate 4 and the ground electrode 5 are integrated by rotating. The high voltage electrode 3, arrester element stack 4 and ground electrode 5 integrated in this way are accommodated in the insertion hole 16 of the insulating cylinder 1 after the high voltage spring S is accommodated in the accommodation hole 31 of the high voltage electrode 3. 3 is inserted toward the conductor 2 side. In this case, it is preferable that both ends of the two conductive members Sa inserted into the high-pressure side spring S are folded back to the outside of the high-pressure side spring S.

  Next, the insulating case 1 incorporating the spring 8 and the integrated high voltage electrode 3, arrester element laminate 4 and ground electrode 5 is inserted into the metal case 6, and the tip end side of the metal case 6 is annularly shaped. The tip end of the bolt V2 that is in contact with the outer wall of the device case C via the packing P and is further inserted into the bolt insertion hole 65 is screwed into the screw hole of the embedded fitting 95 of the fixed bushing 9. As a result, the metal case 6 is hermetically attached to the outer wall of the device case C, and the tip of the arrester (the tip of the insulating cylinder 1) is pushed into the receiving port 92 of the fixed bushing 9 so that the head 21 of the conductor 2 is A tongue piece (not shown) that is plugged into the conductor insertion hole 94 of the fixed bushing 9 and that constitutes the conductor connector (multi-contact) 24 disposed in the head 21 is electrically connected to the inner peripheral surface of the conductor insertion hole 94. Will come into contact.

According to the mounting portion of the arrester having such a configuration, the metal case 6 is attached to the outer wall of the device case C by the bolt V2, so that the spring 8 is engaged with the locking surface 52a of the ground electrode 5 and the locking surface 63b of the metal case 6. The high-pressure side spring S is compressed between the conductor lead-out portion 22 and the high-voltage electrode 3, and the spring force in the axial direction is urged against the spring 8 and the high-pressure side spring S. As a result, the ground electrode 5, the arrester element laminate 4 and the high voltage electrode 3 are pressed toward the receiving port 92 side of the fixed bushing 9 and the axial push against the ground electrode 5, arrester element laminate 4 and the high voltage electrode 3 is pressed. The pressure is applied to the fitting surface (interface) between the inner peripheral surface of the receiving port 92 of the fixed bushing 9 and the tapered outer surface 13 of the distal end portion 11 of the insulating cylinder 1 through the tapered outer surface 22 a of the lead portion 22 of the conductor 2. It is applied in a direction substantially orthogonal, and as a result, the dielectric breakdown at the interface can be prevented by effectively acting the axial pressing force as the surface pressure. Further, due to the synergistic effect of the spring force of the spring 8 and the high-pressure side spring S, a predetermined surface pressure is applied between the high-voltage electrode 3 and the arrester element 41, between the arrester element 41, and between the arrester element 41 and the ground electrode 5. It is also possible to prevent the arrester element 41 from vibrating during movement, and further, by providing a weak point portion for releasing pressure on a part of the sealing member 7 that closes the opening on the rear end side of the metal case 6, Specifically, by providing a thin and easily deformable pressure release plate 72 on the inner periphery of the locking portion 63, when a large current flows and the arrester element 41 is broken, the ground electrode 5 is increased due to an increase in pressure in the insulating cylinder 1. Is pushed out to the rear end side (opening side) of the metal case 6, and as a result, the rod 53 is pushed out to the opening side, the pressure release plate 72 is bent, and the lid member 71 jumps out of the opening. Thereby, the pressure in the insulating cylinder 1 is released to the outside, and the sealing by the sealing member 7 is released at a pressure lower than the breaking pressure of the insulating cylinder 1, thereby preventing the arrester element 41 and the bushing 9 from being scattered. You can also
[Example 2]
FIG. 4 is a partial cross-sectional view showing another embodiment of the arrester of the present invention. In the figure, parts common to those in FIGS. 1 to 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  4, in this embodiment, in place of the conductor 2 shown in FIG. 1, a conductor 2 ′ having an accommodation hole 22b for accommodating the high-pressure side spring S on the side facing the high-voltage electrode 3 of the lead portion 22 ′. Is used. The housing hole 22b is provided concentrically with the conductor 2 '.

  In this embodiment, the high-pressure side spring S can be stably disposed as in the first embodiment by fitting the tip of the high-pressure side spring S into the storage hole 22b.

  Further, in this embodiment, a rod-like extension portion 22c protrudes from the leading end portion of the lead-out portion 22 ', and a plug 21' separate from the protruding extension portion 22c is fitted.

  Also in this embodiment, as in the first embodiment, the plug 21 ′ as the conductor 2 ′ can be plug-in connected to the conductor insertion hole 94 of the fixed bushing 9.

  The present invention can be changed and modified as follows within the scope of the claims.

  First, in the above-described embodiment, the case where a housing hole for housing a spring is provided on either the side of the conductor facing the high-voltage electrode or the side of the high-voltage electrode facing the conductor is described. A housing hole for housing the spring may be provided on both the side of the conductor facing the high-voltage electrode and the side of the high-voltage electrode facing the conductor.

  Secondly, in the above-described embodiment, the insulating cylinder 1 provided with the large diameter portion is described, but an insulating cylinder having no large diameter portion may be used.

  Thirdly, in the above-described embodiment, the case where the high-voltage spring S is disposed between the conductor 2 and the high-voltage electrode 3 has been described. However, the high-voltage spring S is disposed between the conductor 2 and the high-voltage electrode 3. It does not have to be installed.

The partial sectional view of the attachment part of the arrester in the 1st example of the present invention. The partial sectional view which expanded the tip part side of the arrester in the 1st example of the present invention. The partial sectional view which expanded the rear end part side of the arrester in the 1st example of the present invention. The fragmentary sectional view of the arrester in the 2nd example of the present invention. The partial cross section figure of the conventional arrester. The partial cross section figure of the conventional arrester.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Insulating cylinder 13 ... Tapered outer surface 2 ... Conductor 22a ... Tapered outer surface 3 ... High voltage electrode 4 ... Arrestor element laminated body 5 ... Ground electrode 6 ... Metal case 63 ... Locking part 7 ... Sealing member 71 ... Lid member 72 ... Pressure release plate 8 ... Spring 81 ... Conductive member 9 ... Fixed bushing 92 ... Receptor S ..High-pressure side spring C ... Equipment case

Claims (8)

An insulating cylinder having a conductor at the tip, an arrester element laminate inserted into the insulating cylinder via a high-voltage electrode, and a ground electrode disposed on the rear end side of the arrester element laminate,
An arrester characterized in that a taper outer surface is provided on the outer periphery of the conductor, the taper outer surface sequentially increasing in diameter toward the rear end of the conductor at a predetermined taper angle. An insulating cylinder having a conductor at the tip, an arrester element laminate inserted into the insulating cylinder via a high-voltage electrode, a ground electrode disposed on the rear end side of the arrester element laminate, and the ground A coiled spring disposed concentrically with the insulating cylinder on the rear end side of the electrode, a metal case surrounding the insulating cylinder, the ground electrode and the spring, and a rear end side of the metal case A sealing member attached to the opening,
An arrester characterized in that a taper outer surface is provided on the outer periphery of the conductor, the taper outer surface sequentially increasing in diameter toward the rear end of the conductor at a predetermined taper angle.   The taper outer surface which diameter-expands one by one toward the rear-end part direction of the said insulation cylinder is provided in the outer periphery of the front-end | tip part of the said insulation cylinder by the predetermined taper angle. Arresta.   The arrester according to claim 3, wherein the taper angle of the conductor is substantially equal to the taper angle of the insulating cylinder.   The housing hole for housing a spring is provided on at least one of the side of the conductor facing the high-voltage electrode and the side of the high-voltage electrode facing the conductor. 4. Arrester of any one of 4 items.   The arrester according to any one of claims 1 to 5, wherein a plug is attached to an outer periphery of a tip portion of the conductor. A device case containing an electrical device and partially having a through-hole, a fixed bushing disposed inside the device case, and the arrester according to any one of claims 1 to 6,
On the rear end side of the fixed bushing is provided a receiving port having a tapered inner surface that gradually decreases in diameter toward the front end of the fixed bushing at a predetermined taper angle,
The mounting portion of the arrester, wherein the tip of the arrester is mounted inside the fixed bushing.   8. The arrester mounting portion according to claim 7, wherein the taper angle of the conductor is substantially equal to the taper angle of the receiving port.

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