JPH0963808A - Arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable to maintain rigidity of an arrester when a plurality of resistance elements are arranged in the state of lamination, and preventing the change of contact pressure between mutual resistance elements and between the resistance elements and terminal metal fixtures which is to be caused by thermal telescopic motion of the resistance elements according to the change of peripheral temperature. SOLUTION: In an arrester wherein nonlinear resistance elements 24 are pinched between a pair of terminal metal fixtures 31, 32 and an insulating covering layer 36 is formed around the resistance elements 24 and a pair of the terminal metal fixtures 31, 32, the resistance elements 24 are accommodated in an insulating cylinder 21. Holders 28 having spring members 30 are anchored and held on both ends of the insulating cylinder 21. The terminal metal fixtures 31, 32 are threadingly attached to each holder 28 and brought into compressively contact with the end surfaces of the resistance elements 24 by the energizing force of the spring members 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester for protecting a distribution line or the like from a lightning surge, and more particularly to a coupling structure of a non-linear resistance element and a terminal fitting.

[0002]

2. Description of the Related Art As a conventional lightning arrester of this type, one having a structure as disclosed in, for example, Japanese Utility Model Publication No. 2-14285 is known. In this conventional structure, as shown in FIG. 5, a through hole 42 extending in the axial direction is formed at the center of a non-linear resistance element 41 of zinc oxide (ZnO) type, and the through hole 42 has a fiber reinforced plastic (FRP). ) Etc. are inserted. The terminal fitting 4 is attached to the threaded portions of both ends of the insulating rod 43 through the disc electrode 44 and the spring washer 45.
6, 47 are screwed together, and by tightening these terminal fittings 46, 47, the resistance element 41 and both terminal fittings 46, 47 are electrically and mechanically coupled in series.

An insulating coating layer 48 made of a highly elastic insulator such as ethylene-propylene copolymer rubber is formed on the outer circumferences of the non-linear resistance element 41 and the terminal fittings 46 and 47. Further, when the insulating coating layer 48 is formed, the gap between the through hole 42 of the resistance element 41 and the insulating rod 43 is filled with an insulating material to form the inner insulating layer 49, so that the electrical insulation inside is strengthened. There is.

[0004]

In the conventional lightning arrester of this type, when the rated voltage becomes higher, the number of non-linear resistance elements 41 is increased so that the plurality of resistance elements 41 are connected between the terminal fittings 46 and 47. It is necessary to sandwich them in a laminated state. However, when a plurality of resistance elements 41 are arranged in a stacked state in this way, the resistance elements 41, the insulating rods 43, and the like repeat thermal expansion and contraction due to a change in ambient temperature, and the resistance elements 41 and the resistance elements 41 are connected to each other. There is a problem that the contact pressure between the terminal metal fittings 46 and 47 easily fluctuates.

Further, when the number of laminated resistance elements 41 increases, the arrester becomes long-axis-shaped, so that there is a problem in that the rigidity is reduced and it is easily damaged by an unexpected external force. Furthermore, when the plurality of resistance elements 41 are arranged in a stacked state as described above, the gap between the through hole 42 of the resistance element 41 and the insulating rod 43 becomes longer in the axial direction. Therefore, when filling the inside of the voids with an insulating material to form the inner insulating layer 49, it is necessary to increase the filling pressure or lengthen the filling time, which also complicates the molding. there were.

The present invention has been made by paying attention to the problems existing in such conventional techniques. The purpose is that even when a plurality of resistance elements are arranged in a stacked state, the contact pressure between the resistance elements and between the resistance elements and the terminal fittings is caused by thermal expansion and contraction of the resistance elements, etc. due to changes in ambient temperature. Another object of the present invention is to provide a lightning arrester capable of preventing the fluctuation of the electric shock and increasing the rigidity and the resistance to external force.

[0007] Another object of the present invention is as follows.
Even when a plurality of resistance elements are arranged in a stacked state, it is not necessary to increase the filling pressure or lengthen the filling time, and it is possible to easily fill the inner voids with an insulating material to shorten the inner insulating layer in a short time. The present invention is to provide a lightning arrester that can be formed.

[0008]

Means for Solving the Problems In order to achieve the above object, in the invention according to claim 1, a non-linear resistance element is sandwiched between a pair of terminal fittings, and an insulating coating layer is provided around them. In a lightning arrester formed by forming a resistance element in an insulating cylinder, a holder having elastic members is locked and held at both ends of the insulating cylinder, the terminal fitting is fixed to the holder, and It is pressed against the end face of the resistance element by the urging force.

According to a second aspect of the invention, in the lightning arrester according to the first aspect, the elastic member of the holder has a plurality of locking pieces projectingly provided on the outer periphery thereof so as to be able to engage with the locking grooves of the insulating cylinder. It consists of leaf springs.

According to a third aspect of the present invention, in the lightning arrester according to the second aspect, the locking groove is formed on the inner peripheral surface of the insulating cylinder, and the locking piece of the elastic member is engaged with the end surface of the insulating cylinder. A notch is formed for guiding into the stop groove.

According to a fourth aspect of the present invention, in the lightning arrester according to the second aspect, through holes are formed between the locking pieces of the elastic member in a state where the holder is locked and held at both ends of the insulating cylinder. It was done so.

Therefore, at the time of assembling the lightning arrester according to the first aspect, the resistance element is housed in the insulating cylinder, and the holder having the elastic member is locked and held at both ends of the insulating cylinder. After that, when the terminal fittings are fixed to both holders, each terminal fitting is pressed against the end face of the resistance element by the urging force of the elastic member, and the resistance element and both terminal fittings are electrically and mechanically coupled in series. In this state, if an insulating coating layer made of a highly elastic insulator such as rubber is formed around the insulating cylinder and both terminal fittings, the insulating material is filled in the space between the insulating cylinder and the resistance element and the inner insulation is formed. A layer is formed.

For this reason, even when the rated voltage becomes high and a plurality of resistance elements are arranged in a stacked state, thermal expansion and contraction due to changes in ambient temperature cause mutual expansion between the resistance elements and between the resistance element and the terminal fitting. It is possible to prevent the contact pressure from fluctuating.

Further, in the lightning arrester according to the second and third aspects, when the holder is assembled to both ends of the insulating cylinder, the locking pieces of the elastic member are inserted into the locking groove from the notches on both end surfaces of the insulating cylinder. The locking piece is locked and retained in the locking groove by being guided to and rotated. Therefore, the holders can be easily attached to both ends of the insulating cylinder in a short time.

Further, in the lightning arrester according to a fourth aspect, when the insulating coating layer is formed around the insulating cylinder and both terminal fittings, a gap between the insulating cylinder and the resistance element is formed from the through holes at both ends of the insulating cylinder. Filled with insulation to form the inner insulation layer.
Therefore, even when a plurality of resistance elements are arranged in a stacked state, there is no need to increase the filling pressure or lengthen the filling time, and easily fill the voids inside with an insulator,
The inner insulating layer can be formed in a short time.

Moreover, in the lightning arrester according to the fourth aspect, the insulating coating layer and the inner insulating layer are integrally formed through the through holes at both ends of the insulating cylinder. For this reason, if the resistance element is destroyed by an excessive lightning surge and a follow-up arc occurs, the through holes at both ends of the insulating cylinder are opened and the internal pressure is reduced even if the insulating cylinder does not have pressure relief holes. Is easily released. Therefore, it is possible to prevent the entire arrester from being crushed.

[0017]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. First, to describe the overall configuration of the lightning arrester, as shown in FIG. 2, the support base 11 is made of concrete and mounted on a utility pole (not shown). The support insulator 12 is mounted on the support base 11 by bolts 13 and nuts 14, and an electric wire 15 is fixed to the upper end of the support insulator 12. The mounting member 16 is mounted on the lower surface of the support base 11 by the bolts 13 and nuts 14, and a lightning arrester 17 is mounted on the tip thereof.

A ring-shaped arcing horn 18 is attached to the end of the lightning arrester 17 on the voltage-charging side so as to surround the support insulator 12, and a predetermined air discharge gap G1 is formed between it and the wire 15. . The washer 19 is attached to the lower surface of the support base 11 together with the mounting bracket 16,
The ground wire 20 is pressure-welded between the and the mounting bracket 16. The grounding side end of the lightning arrester 17 is grounded via the mounting member 16 and the ground wire 20.

In this lightning arrester, when a surge current caused by a lightning strike is applied to the electric wire 15, the electric current is discharged from the electric wire 15 to the arcing horn 18 through the air discharge gap G1 and built in the lightning arrester 17. Flow into the non-linear resistance element described later. Further, the surge current is discharged from the ground-side end of the lightning arrester 17 to the ground through the fitting 16 and the ground wire 20, and the subsequent current generated thereafter is
It is suppressed and blocked by the air discharge gap G1 and the resistance element in the lightning arrester 17.

Next, the structure of the lightning arrester 17 will be described in detail. As shown in FIGS.
Is formed into a cylindrical shape by FRP or the like, and annular locking grooves 22 are formed on the inner peripheral surfaces of both ends thereof. The four notches 23 are formed on both end surfaces of the insulating cylinder 21 at equal intervals,
Their inner ends communicate with the locking groove 22.

The plurality of non-linear resistance elements 24 are made of zinc oxide (ZnO) as a main material and have a non-linear voltage-current characteristic, and are stacked in series with the intermediate electrode 25 interposed therebetween. It is housed inside the insulating cylinder 21. The coated electrodes 26 are formed on both end surfaces of the resistance element 24 in the laminated state by a metal spraying method or the like, and the disc electrodes 27 are bonded and arranged on the outer surfaces thereof.

A pair of holders 28 are held and retained at both ends of the insulating cylinder 21, and a cylindrical body 29 located at the center and a spring body 30 as an elastic member composed of a leaf spring brazed and fixed to the outer peripheral surface thereof. It has and. A female screw 29a is formed on the inner peripheral surface of the tubular body 29, and four locking pieces 30a are provided so as to project on the outer periphery of the spring body 30. Then, after guiding the locking pieces 30a into the locking grooves 22 from the notches 23 of the insulating cylinder 21, the holders 28 are rotated by a predetermined angle to lock the locking pieces 30a in the locking grooves 22. Is held.

The pair of terminal fittings 31 and 32 includes a screw portion 31.
Each of the holders 28 is attached to the center of the holder 28 by screwing a and 32a onto the female screw 29a of the tubular body 29 of the holder 28. And this terminal fitting 3
In the screwed state of 1, 32, both terminal fittings 31, 32 are pressed against the disk electrode 27 by the urging force of the spring body 30 of each holder 28, and each resistance element 24 and both terminal fittings 31, 32 are connected in series. It is electrically and mechanically coupled in a state.

The mounting screw 33 is formed on the tip of the ground side terminal fitting 31, and the arrester 17 is mounted on the tip of the mounting fitting 16 using the mounting screw 33. Screw hole 3
4 is formed at the tip of the power-charging side terminal fitting 32, and the arcing horn 18 is attached to the power-charging side end of the lightning arrester 17 by using this screw hole 34.

Then, as described above, the holders 28 are locked and held at both ends of the insulating cylinder 21, and the terminal fittings 31 and 32 are screwed to the holders 28, respectively. A through hole 35 is formed between the stop pieces 30a. Therefore, the gaps between the outer peripheral surfaces of the resistance element 24 and both terminal fittings 31, 32 and the inner peripheral surface of the insulating cylinder 21 are opened outward at both ends of the insulating cylinder 21 through the through holes 35. .

The insulating coating layer 36 is formed by molding an insulating material having a high elasticity, such as rubber, to form the resistance element 24 and both terminal fittings 3.
A plurality of insulating folds 36a are formed on the outer peripheral surface of the insulating cylinder 21 so as to project therefrom. The inner insulating layer 37 is formed by filling the space between the outer peripheral surfaces of the resistance element 24 and the terminal fittings 31, 32 and the inner peripheral surface of the insulating cylinder 21 with an insulating material when the insulating coating layer 36 is formed. The inner insulating layer 37 enhances the internal electrical insulation.

Next, the operation of the lightning arrester constructed as above will be described. When assembling this lightning arrester 17, first, a plurality of non-linear resistance elements 24 are stacked and housed in the insulating cylinder 21, and the disk electrodes are formed on the coated electrodes 26 at both ends of the resistance element 24. 27 is arranged by joining. Next, the holder 28 having the spring bodies 30 is locked and held at both ends of the insulating cylinder 21. In this case, as shown by the chain line in FIG. 4, if the locking piece 30a of the spring body 30 is guided into the locking groove 22 through the notches 23 on both end surfaces of the insulating cylinder 21 and rotated, the locking piece 30a is obtained. Is held in the locking groove 22 so that the holder 28 can be easily assembled to both ends of the insulating cylinder 21.

After that, the tubular members 29 in both holders 28
The female screw 29a of the
When 32a is screwed, the inner end surfaces of the terminal fittings 31, 32 are pressed against the disk electrodes 27 on both end surfaces of the resistance element 24 by the biasing force of the spring body 30. As a result, the resistance element 24
The two terminal fittings 31, 32 are electrically and mechanically connected in series.

In this state, the insulating cylinder 21 and both terminal fittings 3
An insulating coating layer 36 made of an insulating material such as rubber having a high elasticity is formed around 1, 32. At this time, from the through holes 35 at both ends of the insulating cylinder 21, the resistance element 24 and both terminal fittings 3 are inserted.
The space between the outer peripheral surfaces of 1, 32 and the inner peripheral surface of the insulating cylinder 21 is filled with an insulating material to form the inner insulating layer 37.

As described above, this embodiment has the following advantages. (1) Even when the rated voltage becomes high and a plurality of resistance elements 24 are arranged in a stacked state, it is not necessary to increase the filling pressure or lengthen the filling time, and the insulator can be easily provided in the internal void. To form the inner insulating layer 37 in a short time. (2) When the lightning arrester 17 manufactured as described above is incorporated in the lightning arrester as shown in FIG. 2, the resistance element 24 in the lightning arrester 17 is urged by the spring body 30 of the holder 28 so that both terminal metal fittings are urged. It is strongly sandwiched and held between 31 and 32. Therefore, even when a plurality of resistance elements 24 are arranged in a stacked state, thermal expansion and contraction of the resistance elements 24 due to a change in ambient temperature causes the resistance elements 24 to come into contact with each other and between the resistance elements 24 and the terminal fittings 31, 32. It is possible to prevent the contact pressure from changing. (3) Further, the resistance element 24 is laminated inside the insulating cylinder 21, and is held at both ends of the insulating cylinder 21 via both the terminal fittings 31 and 32, so that even if an external force is applied to the lightning arrester, it is relieved by the spring body 30. As a result, internal damage due to contact pressure drop and twisting is prevented. (4) Further, in the lightning arrester 17, the insulating coating layer 36 and the inner insulating layer 37 are integrally formed via the through holes 35 at both ends of the insulating cylinder 21. Therefore, when the resistance element 24 is destroyed by an excessive lightning surge and a follow-up arc is generated, the through holes 35 at both ends of the insulating cylinder 21 are opened even if the pressure releasing hole is not formed in the insulating cylinder 21. The internal pressure is released easily. Therefore, it is possible to prevent the entire arrester 17 from being crushed.

The present invention can be embodied with the following modifications. (A) A frustoconical coil spring is used as the spring body 30 of the holder 28, and its small-diameter side end portion is fixed to the outer circumference of the tubular body 29, and the large-diameter side end portion is made to the inner circumference of both ends of the insulating cylinder 21. Be configured to lock. (B) The terminal fittings 31 and 32 should be fixed to the holder 28 by means of engaging and recessing means. (C) The inner insulating layer 3 is provided with a plurality of through holes in the insulating cylinder 21.
7 and the release of pressure when a follow-up arc occurs. (D) As the holder 28, the one in which the tubular body 29 and the spring body 30 are integrally formed is used. (E) Use plastic having a predetermined hardness and elasticity as the elastic member.

Further, the technical idea understood from the above embodiment will be described below. (1) The arrester according to claim 1, wherein the terminal fitting is screwed to a holder. According to this structure, the terminal fitting can be securely fixed at a predetermined position by screwing the terminal fitting into the holder. (2) The arrester according to claim 2, wherein the plurality of locking pieces extend radially from the holder and are arranged symmetrically. According to this configuration, the non-linear resistance element is uniformly pressed,
It can be sandwiched between a pair of terminal fittings. (3) The elastic member of the holder is a frustoconical coil spring, the small diameter side end portion of which is fixed to the outer circumference of the holder and the large diameter side end portion of which is locked to the inner circumference of the end portion of the insulating cylinder. The lightning arrester described in 1. According to this structure, the ends of the coil spring can be locked in the locking grooves of the insulating cylinder, and the holders can be easily and quickly assembled to both ends of the insulating cylinder.

[0033]

EFFECTS OF THE INVENTION Since the present invention is configured as described above, it has the following effects. According to the invention as set forth in claim 1, even when a plurality of resistance elements are arranged in a laminated state, thermal expansion and contraction of the resistance elements and the like due to a change in ambient temperature causes the resistance elements to come into contact with each other and between the resistance elements and the terminal fitting. It is possible to prevent the contact pressure between them from fluctuating.

Further, even if an external force is applied to the lightning arrester, its rigidity can be maintained, and the external force can be mitigated by the elastic member locked to the insulating cylinder to prevent internal damage. Claim 2
According to the invention as set forth in claim 3, the elastic member of the holder can be locked in the locking groove of the insulating cylinder, and the holder can be easily and quickly assembled to both ends of the insulating cylinder.

According to the fourth aspect of the invention, even when a plurality of resistance elements are arranged in a laminated state, there is no need to increase the filling pressure or lengthen the filling time, and both ends of the insulating cylinder are An inner insulating layer can be formed in a short time by easily filling an inner space from the through hole with an insulator.

According to the invention described in claim 4, when the resistance element is destroyed by an excessive lightning surge and a follow-up arc occurs, the insulating cylinder is not formed even if the pressure release hole is formed. The internal pressure can be released by opening the through holes at both ends of the lightning protection device, and the risk of crushing the entire lightning arrester can be prevented.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a lightning arrester of the present invention.

FIG. 2 is a front view of a lightning arrester including the lightning arrester.

FIG. 3 is a partially enlarged cross-sectional view showing a process of assembling a terminal fitting to an end portion of an insulating cylinder.

FIG. 4 is a fragmentary plan view of a main portion of FIG.

FIG. 5 is a vertical cross-sectional view showing a conventional lightning arrester.

[Explanation of symbols]

17 ... Lightning arrester, 21 ... Insulating cylinder, 22 ... Locking groove, 23 ... Insertion hole, 24 ... Non-linear resistance element, 28 ... Holder, 29 ...
Cylindrical body, 29a ... Female screw, 30 ... Spring body as elastic member, 30a ... Locking piece, 31 ... Ground side terminal fitting, 32 ...
Terminal fittings on the power-supply side, 35 ... through holes, 36 ... Insulation coating layer, 3
7 ... Inner insulating layer.

Claims (4)

[Claims] 1. A lightning arrester in which a non-linear resistance element is sandwiched between a pair of terminal fittings and an insulating coating layer is formed around them, wherein the resistance element is housed in an insulating cylinder, and the insulating cylinder is formed. A lightning arrester in which a holder having elastic members is locked and held at both ends of the terminal, the terminal fittings are fixed to the holder, and the end faces of the resistance element are pressed against each other by the urging force of the elastic members. 2. The lightning arrester according to claim 1, wherein the elastic member of the holder is a leaf spring having a plurality of locking pieces projecting from the outer periphery thereof and capable of engaging with the locking grooves of the insulating cylinder. 3. The locking groove is formed on the inner peripheral surface of the insulating cylinder,
The lightning arrester according to claim 2, wherein a notch for guiding the locking piece of the elastic member into the locking groove is formed on the end surface of the insulating cylinder. 4. The lightning arrester according to claim 2, wherein a through hole is formed between the locking pieces of the elastic member while the holder is locked and held at both ends of the insulating cylinder.