JPS63169702A - Arrestor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a lightning arrester equipped with a non-linear resistance element.

(Prior Art) Conventionally, as shown in FIG.
A lower M4 is provided between the insulator tube 2 and a cap fitting (hereinafter referred to as a lower cap fitting) 3 attached to the lower end thereof, and a cap fitting (hereinafter referred to as an upper cap fitting) attached to the insulator tube 2 and its upper end. (referred to as metal fittings) 5 and the upper lid 6.
In addition, there is a structure in which a predetermined number of non-linear resistance elements 7 and spacers 8 mainly made of zinc oxide etc. are stacked in series between the two cap fittings 3.5. .

(Problems to be Solved by the Invention) In general, in the lightning arrester 1, if a follow-on current is generated inside due to moisture intrusion or excessive lightning surge, and it becomes impossible to interrupt or restore the flow, the container such as the insulator tube 2 etc. will be crushed. It was necessary to take precautions from the viewpoint of public safety and fire prevention.

In the conventional lightning arrester 1, a protection tube made of FRP or the like is inserted into the inner wall of the insulator tube 2 to shield the uneven heat of the follow-on arc to the insulator tube 2, and in consideration of melting of the upper and lower cap fittings 5.3, etc. Measures such as making the lightning arrester 1 thicker have been taken, but this poses problems in terms of the size and cost of the arrester 1.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention includes a spacer made of a heat-resistant insulating material such as porcelain or ceramics, and a spacer that can be shut off and cannot be restored within the arrester. A technical measure is adopted in which the spacer is short-circuited with a conductor that easily melts away when a follow-on current flows.

(Operation) When a follow-on current that cannot be interrupted or restored flows inside the arrester, the conductor shorting the insulating spacer is vaporized by Joule heat and forms an arc column over almost the entire height, instantly raising the inside of the arrester to a high temperature. By increasing the pressure and increasing the back pressure, the high-temperature, high-pressure gas is immediately released to the outside of the arrester and the arc ignition voltage is lower than that inside the arrester, so the influence of uneven heat from the follow-on arc inside the arrester is eliminated in a short time, and insulators etc. prevent thermal damage to containers.

(Example) Next, the first to third embodiments embodying the lightning arrester of the present invention will be described.
This will be explained based on the diagram.

As shown in FIG. 1, the lightning arrester 1 is supported in its insulator tube 2 by a band fitting 10 on a support part 9 of a base (not shown).
Fixed. The insulator tube 2 is formed of porcelain into a cylindrical shape, and has annular projections 2b and 2a on the outer circumferential side of its upper and lower ends.
A barrier 11 made of a heat-resistant insulating material is attached to the inner circumferential surface of the insulator tube 2 as required.

The lower end of the insulator tube 2 is connected via an O-ring 12 to an umbrella-shaped lower lid 4 made of a highly elastic metal material such as stainless steel.
The lower cover 4 is attached to the lower part of the insulator tube 2 so as to be sealed by the lower cover 4.
A lower cap metal fitting 3 that presses from below is fixed.

On the outer circumferential side of the lower cap metal fitting 3, approximately tongue-shaped protrusions 3a are formed protrudingly at positions dividing the circumference into thirds, and between two adjacent protrusions 3a, the tips thereof face diagonally upward. A discharge end 3X is formed (FIG. 2).

Furthermore, drain grooves 3ztfi and ffl are formed in the portion of the lower cap fitting 3 between two adjacent projecting pieces 3a where the discharge end 3X is not provided.

The lower cap fitting 3 is secured to the insulator tube 2 by sandwiching the annular protrusion 2a between the protruding piece 3a and the compression plates 1 to 3, and tightening them with the holes 1 to 14 and nuts 1 to 15. It is attached.

In the lower cap fitting 3, a tongue-shaped lead wire attachment portion 3y is formed protruding from one of the projecting pieces 3a, and the lead wire attachment is performed by fixing the ground side lead wire 16 to the portion 3y with a bolt 17 and a nut 18. ing.

A conductive coil spring 19 is provided on the lower lid 4, and a desiccant 20 is placed using the space inside the spring. At the upper end of the coil spring 19, a lower electrode 21 having a diagonal side shape is held with its legs fitted into the coil spring 19.

A columnar spacer 8 made of a heat-resistant insulating material such as porcelain or ceramics is placed on the lower electrode 21 via a disk-shaped plate electrode 22, and a columnar spacer 8 made of a heat-resistant insulating material such as porcelain or ceramics is placed on top of the spacer 8. Column-shaped non-linear resistance elements 7 are stacked, and spacers 8 and non-linear resistance cables 7 are stacked on top of each other in series.

As shown in FIG. 3, each of the two spacers 4-8 has a groove 8a formed at its side from the lower end surface to the upper end surface, and the groove 8a is filled with 3n, l'b, Afl, CLI or other low melting point metal or A substantially linear conductor 23 made of a low melting point alloy or the like having at least one of these components is provided, and when a lightning surge within the rated value flows through the nonlinear resistance element 7, the lightning surge will not melt, but the If a follow-on current exceeding a predetermined level, that is, a follow-on current that cannot be cut off or restored due to a lightning surge or aging deterioration of the non-linear resistance element 7, flows, the conductor 23 will be heated by 6 joules due to the follow-on current.
It is easily vaporized or fused within a cycle time.

A forest-shaped upper electrode 25 is provided above the non-linear resistance element 7 at the top with a plate-shaped electrode 24 interposed therebetween. An upper cap fitting 5 is attached and fixed to the upper end of the insulator tube 2, and the opening thereof is connected to an umbrella-shaped upper cover made of a highly elastic metal material such as stainless steel, similar to the lower cover 3, via an O-ring 26. 6 and by compressing the coil spring 19, the nonlinear resistance element 7 and the spacer 8 are held in pressure contact within the insulator tube 2. The space S within the insulator tube 2 is kept airtight by filling with an inert gas or the like as necessary. Similar to the lower cap metal fitting 3, the upper cap metal fitting 5 also has a discharge Da5x formed therein.

Further, the upper cap fitting 5 is fixed to the insulator tube 2 by sandwiching the annular protrusion 2b of the insulator tube 2 between the compression plate 27 and the protruding piece 5a of the upper cap fitting 5, and tightening them with bolts 28 and nuts 29. ing.

A lead wire attachment portion 5y is also formed in the upper cap metal fitting 5, and a power supply side lead wire 30 is fixed to the lead wire attachment portion 5y by a bolt 31 and nuts 1 to 32. Note that the lead wire 30 on the power supply side is connected to a line.

An insulating cover 33 is provided on the upper cap fitting 5 to protect the live portion of the lightning arrester 1.

Next, to explain the operation and effect of this embodiment, when a lightning surge enters the line (not shown), the lightning surge is caused by the power-supplying side lead wire 30 - upper cap fitting 5 - upper cover 6 - upper electrode 25 - plate. shaped electrode 24 - nonlinear resistance element 7 - conductor 2
3-Nonlinear resistance element 7-Conductor 23-Plate electrode 22-Lower voltage t1i! 21-coil spring 19-lower cap metal fitting 3, and is grounded via the grounding side lead wire 16, but in a situation where the lightning arrester 1 cannot block the follow-on current, the follow-on current flows to the outer surface of the non-linear resistance element 7. A flashover occurs and a follow-on current flows to the conductor 23 of the spacer 8, generating Joule heat, and the conductor 23 of the spacer 8 generates Joule heat.
3 melts or vaporizes, the arc resistance inside the insulator tube 2 rises and becomes higher than the arc resistance outside the insulator tube 2, so that the released gas quickly moves to the outside of the insulator tube 2 and is released.

Therefore, an arc path is bridged between the discharge end 5 The arc disappears.

The process of releasing the internal trailing arc to the outside is estimated as follows. That is, the conductor 23 short-circuiting the insulating spacer 8 melts or evaporates, and an arc column extending almost to the height is formed inside the insulator tube 2, so that the internal space is much smaller than that of the conventional lightning arrester 1. The high-temperature and high-pressure state is reached and the high-temperature gas is blown out to the outside in a state close to atmospheric pressure, but since this gas has a high degree of ionization, the external arc ignition voltage of the lightning arrester 1 is reduced.

On the other hand, inside the arrester 1, a large amount of gas is generated due to the long arc column, which increases the back pressure of gas release and increases the internal arc ignition voltage, so the arc ignition voltage outside is lower than inside. After that, the arc path flashes only outside the lightning arrester 1.

For example, as an accident simulation example, when connected in series to a 60H2,800A constant current circuit for 2.5 seconds, in the conventional lightning arrester 1, the entire insulator 2 collapses and falls, but in the lightning arrester 1 of the present invention, the insulator 2 completely collapses and falls. The upper and lower pressure relief ends were only partially eroded, the insulator tube 2 was not damaged, and there were no fallen objects. Observing the situation during this time using high-speed photographs and electromagnetic oscillographs, it was found that in the case of a demolished item, the arc continued for about 0.2 seconds after the start of energization.
During this period, the insulator tube 2 receives uneven heat due to the arc and is destroyed.However, in the arrester 1 of the present invention, the internal current is discharged to the outside of the arrester 1 within 0.2 seconds after energization starts. It was observed that the internal current was interrupted by a flash arc starting from the pressure relief port.

As is clear from the above observation results, by guiding the discharge of the follow-on arc inside the lightning arrester 1 to the outside for a short period of time and releasing it, it is possible to prevent the breakdown of the W electric appliance, and the lightning arrester 1 of the present invention can be prevented from collapsing. It is clear that this effect can be effectively exerted by.

The present invention is not limited to the above-mentioned embodiments, but can be modified and embodied in the following embodiments, for example.

(1) As shown in FIG. 4, a conductor 23 formed in a foil shape can be attached to the outer peripheral surface of the spacer 8 from the upper end surface side to the lower end surface side of the spacer 8 so as to be electrically conductive. This embodiment is advantageous in that the required number of conductors 23 can be easily removed from the spacer 8.

(2) A method for attaching the conductor 23 to the spacer 8 is to form the conductor 23 separately as a linear body and attach it to the spacer 8.Another method is to attach the conductor 23 to the spacer 8 using the groove 8a formed in the spacer 8.
Alternatively, a method may be adopted in which the conductor is melted and poured into the through hole.

Furthermore, the shapes, numbers, etc. of the nonlinear resistance element 7 and the spaces 98 can be arbitrarily set as long as the technical concept and effects of the present invention are not significantly impaired.

Effects of the Invention As detailed above, the present invention provides that when a follow-on current inside a lightning arrester short-circuits between the cap fittings, the conductor provided in the spacer immediately melts or vaporizes, increasing the arc resistance inside the insulator tube. It has the excellent effect of quickly moving the arc to the outside of the insulator and emitting it. As a result, destruction of the insulator tube etc. due to the high heat of the arc can be prevented.

Furthermore, by appropriately setting the space capacity inside the insulating tube with an insulating spacer, when a follow-on arc occurs inside due to deterioration of a non-linear resistance element, the internal pressure can be rapidly increased and the pressure can be released quickly. It also has the effect of being able to do it. Therefore, destruction of the insulator pipe etc. can be prevented and safety can be maintained.

[Brief explanation of the drawing]

81 is a partial vertical sectional view of the embodiment, FIG. 2 is a plan view of the upper or lower cap fitting, FIG. 3 is a perspective view of the spacer in the embodiment, and FIG. 4 is a perspective view showing another aspect of the spacer. FIG. 5 is a longitudinal sectional view of the prior art. 1... Lightning arrester, 2... Insulator tube, 3... Cap fitting (lower cap fitting), 5... Cap fitting (upper cap fitting), 7... Non-linear resistance element, 8... Spacer , 23... conductor

Claims (1)

[Claims] 1. Cap fittings (3) fixed to both ends of the insulator tube (2).
, 5) In a lightning arrester (1) in which a non-linear resistance element (7) and a spacer (8) are interposed in contact with each other, the spacer (8) is formed of a heat-resistant insulating material such as porcelain or ceramics. , the conductor (23), which will melt when a follow-on current of a predetermined level or higher flows into the lightning arrester (1), is replaced by the spacer (8).
) A lightning arrester characterized by being installed in 2. The lightning arrester according to claim 1, wherein the conductor (23) is a metal foil and is provided on the surface of the spacer (8). 3. The lightning arrester according to claim 1, wherein the spacer (8) has a columnar shape.