JPH0351923Y2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention particularly relates to lightning arresters used in power distribution lines.

(Prior art) Conventionally, this type of lightning arrester has a structure in which a plurality of nonlinear resistance elements mainly composed of zinc oxide are stacked and housed in a hollow part of an insulator body, and pressure relief holes are provided at both ends of the insulator body. It is known that cap fittings are attached to each cap fitting to electrically connect the non-linear resistance elements at both ends to both cap fittings, and that both cap fittings are further provided with a sealing member that always closes the pressure relief hole. ing.

(Problem that the invention aims to solve) However, if an accident occurs that generates a follow-on arc inside the insulator body of this lightning arrester, and the arc current is less than a few thousand A, the inside of the hollow part of the insulator body The arc is difficult to migrate to the outside of the insulator, and in many cases, the follow-on arc causes uneven heat damage to the insulator body from the inside, causing its fragments to scatter.

This invention was devised to solve the above problems, and its purpose is to eliminate the arc when a follow-on arc occurs inside the insulator body, regardless of the value of the follow-on current. To provide a lightning arrester capable of reliably forming an external arc path by releasing internal pressure from a cap electrode to the outside of an insulator body, thereby preventing destruction of the insulator body and its scattering. It is in.

Structure of the invention (Means for solving the problem) In order to achieve the above object, this invention forms a hollow part that opens at both ends in the insulator body, and divides the hollow part with a partition wall to form a pair. One housing chamber accommodates a non-linear resistance element, the other housing chamber houses a fuse section that is blown by a follow-on current to electrically connect the two, and a hollow A structure is adopted in which the openings at both ends of the storage chamber are always closed, and cap electrodes are provided that can open each opening when the internal pressure of both storage chambers increases.

(Function) Therefore, in this lightning arrester, when lightning enters the distribution line, the lightning surge current flows through the non-linear resistance element, but the following current is blocked. Further, when the element is in a deteriorated state, an arc is generated on the surface of the element in one of the housing chambers, followed by arc discharge due to a follow-on current. This follow-on current blows out the fuse housed in the other accommodation chamber, and arc discharge is also generated by the follow-on flow in the other accommodation chamber. As a result, the internal pressure in both chambers rises rapidly, and the cap electrodes that close the openings at both ends are opened, opening both openings in the insulator body, and as the internal pressure is released, an arc is generated in the insulator body. It is emitted to the outside and an external arc path is reliably formed.

(Example) Hereinafter, an example that embodies this invention will be described based on the drawings.

The lightning arrester 1 of this invention is supported and fixed to an arm 2 of an erection device (not shown) by a support fitting 3.
The insulator body 4 of the lightning arrester 1 is formed of porcelain into a cylindrical shape, and a hollow portion 5 that is open at both ends is formed in the center thereof. A partition wall 6 is provided approximately at the center of the interior of the hollow portion 5, and the partition wall 6 defines a pair of upper and lower storage chambers 7 and 8, and a barrier B made of a heat-resistant insulating material is formed on the inner peripheral surface of the partition wall 6. has been done.

Cap electrodes 9, 1 are provided at both upper and lower ends of the insulator body 4.
0 is fixed. Upper and lower cap electrodes 9, 1
0 is an umbrella-shaped sealing member 12, 13 made of an elastic material (stainless steel in this embodiment) that releasably closes the openings 5a, 5b at both ends of the hollow portion 5 via an O-ring 11; It consists of cap fittings 14 and 15 fixed to both ends of the insulator body 4 so as to support the insulator body 13.

A lightning arrester unit 16 is housed in the upper housing chamber 7, and a slight gap is formed between the inner peripheral surface of the housing chamber 7 and the lightning arrester unit 16. The lightning arrester unit 16 has non-linear resistance elements 17 mainly composed of zinc oxide (ZnO) and current collector plates 18 stacked alternately, and upper and lower electrodes 1 are attached to the elements 17 at both the upper and lower ends.
9 and 20 are joined. Further, the surface of the non-linear resistance element can be reinforced in insulation by covering these with a covering part 21 made of insulating rubber. Note that an O-ring 11 is interposed between the lower electrode 20 and the partition wall 6 to maintain airtightness. Further, a compression spring 22 is interposed between the upper electrode 19 and the seal member 12 to maintain electrical connection between the nonlinear resistance element 17 and the current collector plate 18 and between the lightning arrester unit 16 and the upper cap electrode 9. ensuring proper connection.

On the other hand, a fuse portion 23 is accommodated in the lower accommodation chamber 8 . A lid-shaped electrode 25 is screwed onto the upper end of the voltage-resistant insulating cylinder 24 made of reinforced plastic (FRP), and a lid-shaped electrode 26 is removably attached to the lower end. Both lid-shaped electrodes 25, 26
A low current fuse 28 made of a low melting point alloy is connected between the two through lead wires 27a and 27b, and is blown by subsequent flow. Voltage-proof insulation cylinder 2
4 is provided with an inner cylinder 29 made of urea resin or the like, and when the fuse 28 is fused, the lead wire 2
Arc-extinguishing gas is generated by heat accompanying arc discharge generated between 7a and 27b.
Note that an O-ring 11 is also interposed between the upper lid-shaped electrode 25 and the partition wall 6 to maintain airtightness. This fuse part 23 and the lightning arrester unit 16 are composed of a convex part 20a of the lower electrode 20 that passes through a through hole 6a provided in the partition wall 6, and an upper lid-like electrode 2.
It is fixed by screwing with 5 and is electrically connected. Furthermore, a compression spring 30 is interposed between the lower lid-shaped electrode 26 and the sealing member 13 to ensure that the lower lid-shaped electrode 26 is attached to the voltage-resistant insulating cylinder 24.

Arching horns 14a, 15a are formed obliquely in the upper and lower cap fittings 14, 15 so as to face each other, and the concave base ends thereof constitute pressure relief ports 14b, 15b of the arc jet. A lid 31 made of a polyvinyl chloride resin plate is attached to both pressure relief ports 14b and 15b.

A power supply side lead wire 33 connected to a line of an erection device (not shown) is fixed to the upper cap metal fitting 14 with bolts and nuts. Note that a cover 35 is provided on the upper cap metal fitting 14,
The live parts of the lightning arrester 1 are covered to prevent electric shock and bird damage. Further, a ground side lead wire 34 is fixed to the lower cap metal fitting 15 with bolts and nuts.

Next, the operation of the lightning arrester 1 configured as described above will be explained. When a line (not shown) is struck by lightning, a lightning surge voltage is applied to the installation device of the lightning arrester 1. At this time, in the lightning arrester 1 provided in the erection equipment, the lightning surge current flows from the power supply side lead wire 33 to
It flows through the upper cap metal fitting 14 → upper sealing member 12 → compression spring 22 → upper electrode 19 to the nonlinear resistance element 17, and then current collector plate 18 → lower electrode 20 →
It flows from the fuse part 23 to the compression spring 30 to the lower seal member 13 to the lower cap fitting 15, and is grounded via the ground side lead wire . A follow-on current following this lightning surge current is blocked by the non-linear resistance element 17.

In addition, if lightning strikes a line (not shown) that greatly exceeds the rated duty, or if lightning strikes while the non-linear resistance element 17 has deteriorated, the non-linear resistance element 1
An arc occurs on the surface of 7, followed by a follow-on arc. The low current fuse 28 is blown by the discharge current caused by this follow-on arc, and both lead wires 27
A gap is formed between a and 27b, and a follow-on arc is generated in the gap.

At this time, gas is generated from the nonlinear resistance element 17 in the accommodation chamber 7, but since the gap between the inner peripheral surface of the accommodation chamber 7 and the lightning arrester unit 16 is very small, the internal pressure rises rapidly. . Due to this increase in internal pressure, the upper seal member 12 is reversed as shown by the two-dot chain line, the opening 5a is opened, the lid 31 is scattered, and the internal pressure is released. With this pressure relief, the arc within the accommodation chamber 7 is discharged to the outside from the pressure relief port 14b.

On the other hand, in the storage chamber 8, both lead wires 27a,
Arc-extinguishing gas is generated from the inner cylinder 29 due to the heat generated by the follow-on arc between the arcs 27b and 27b, increasing the internal arc voltage and helping the arc to move outward, and when the internal pressure inside the voltage-resistant insulating cylinder 24 rises rapidly. The lower lid-shaped electrode 26 resists the biasing force of the compression spring 30 and separates from the insulating tube 24 as shown by the two-dot chain line. Therefore, the internal pressure inside the voltage-resistant insulating cylinder 24 is released into the storage chamber 8, and then the lower seal member 13 is turned over as shown by the two-dot chain line to open the opening 5b, and the lid 3
1 is scattered and the internal pressure is released. With this pressure relief, the arc within the accommodation chamber 8 is discharged to the outside from the pressure relief port 15b.

The arcs emitted from both the upper and lower cap fittings 14 and 15 are connected vertically, and an arc path is reliably formed outside the insulator body 4. Therefore, it is possible to prevent the insulator body 4 from being destroyed and to prevent the insulator body 4 and its contents from scattering to the outside.

Effects of the invention As detailed above, according to this invention, even when the discharge current due to follow current is small, the internal pressure can be released by opening both openings using the cap electrodes provided at both the upper and lower ends of the insulator body. , and since the internal arc voltage can be sufficiently increased, the arc is emitted from both the upper and lower cap electrodes during this pressure release, and the insulator body is prevented from being damaged by uneven heat due to the follow-on arc generated inside the insulator body. It has an excellent effect of being able to reliably migrate to the outside.

[Brief explanation of the drawing]

The figure is a partial vertical sectional view showing an embodiment of this invention. 4...Insulator body, 5...Hollow part, 5a, 5b...
...opening, 6...partition, 7, 8...containment chamber, 9,
10... Cap electrode, 17... Non-linear resistance element, 23... Fuse part.

Claims (1)

[Scope of utility model registration request] A hollow portion 5 that opens at both ends is formed in the insulator body 4, and the hollow portion 5 is partitioned by a partition wall 6 to form a pair of storage chambers 7 and 8, one of the storage chambers 7 having a non-linear resistance. In addition to accommodating the element 17, the other accommodating chamber 8 accommodates a fuse portion 23 that is blown by subsequent flow to electrically connect the two.
Furthermore, cap electrodes 9 and 1 are capable of always closing the openings 5a and 5b at both ends of the hollow portion 5 and opening the openings 5a and 5b when the internal pressure of both the storage chambers 7 and 8 rises.
A lightning arrester characterized by providing a zero.