JPH06105566B2 - Lightning arrester - Google Patents

Description

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.

(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, the insulation of conventional insulators
There has been proposed a suspension insulator type lightning arrestor having both a wire support function and a lightning arrester function. As this lightning insulator,
The applicant of the present application proposes that a current limiting element having a non-linear voltage-current characteristic is attached to the cap portion of the insulator body. This lightning insulator accommodates a current limiting element in the inner peripheral surface of the mounting cylinder, that is, in the through hole, and fits and fixes metal upper and lower electrodes on the upper and lower ends of the mounting cylinder. The outer peripheral surface of the element and the through hole were filled with a low melting point glass to fix the current limiting element in the through hole.

(Problems to be Solved by the Invention) However, in such a conventional device, since the current limiting element is melted and fixed to the mounting cylinder by the low melting point glass, the current limiting element deteriorates or exceeds the assumption. When the current limiting element becomes conductive due to a lightning strike, the current limiting element is electrically and mechanically destroyed, so the current limiting element is cracked and the mounting tube is cracked through the glass bonding layer. Therefore, there is a fear that the cap portion is easily damaged.

Configuration of the Invention (Means for Solving Problems) In order to solve the above problems, the present invention fixes a cap metal fitting to a cap-shaped cylindrical head formed in the central upper portion of a cap portion of an insulator body, A pin metal fitting is fitted and fixed inside the head, a through hole is provided in the cap portion, and a current limiting element having a non-linear voltage-current characteristic is fitted in the through hole, and an outer periphery of the current limiting element. The side is covered with a high-strength heat-resistant insulating cylinder having high strength and heat resistance with a predetermined gap, and the high-strength heat-resistant insulating cylinder is embedded between the inner peripheral surface of the through hole and the outer peripheral surface of the current limiting element. As described above, the heat-resistant elastic insulating material is filled, and the upper electrode and the lower electrode are provided at both upper and lower ends of the through hole.

(Operation) In the present invention, when the current limiting element becomes conductive due to a lightning strike,
The propagation of cracks and expansion due to arc heat at the time of current limiting element destruction are absorbed by the heat-resistant elastic insulating material, and the mechanical strength is absorbed by the high-strength heat-resistant insulating cylinder having high strength and heat resistance, resulting in high strength and heat resistance. The deformation of the high-strength heat-resistant insulating cylinder is absorbed by the heat-resistant elastic insulating material filled between the insulating cylinder and the through hole, so that almost no mechanical force acts on the inner peripheral surface of the through hole, and the cap portion The damage and the destruction of the insulator body due to the damage are prevented, and the reliability is improved.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

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.

As shown in FIG. 1, an insulator main body 5 constituting the lightning protection insulator 3.
Is a cap portion 5a, a plurality of concentric fold portions 5b formed in an annular shape on the inner surface of the cap portion 5a, and further, a cylindrical shape with a lid integrally formed on the upper center of the cap portion 5a. It is integrally molded with the head 5c. Further, a cap metal fitting 7 is capped and fixed to the outer periphery of the head portion 5c with cement 6, and an engaging recessed portion 7a is formed in the metal fitting 7, and a pin metal fitting 8 of the lightning protection insulator 3 directly above.
Are engaged with each other. The upper portion of the pin metal fitting 8 is fixed inside the head portion 5c by cement 6, and the lower end thereof is engaged with the engaging concave portion 7a of the cap metal fitting 7 of the lightning protection insulator 3 directly below. In this way, the plurality of lightning protection insulators 3 are connected in series.

As shown in FIG. 1, the cap portion 5a is provided with a plurality of cylindrical mounting portions 5d (not shown in this embodiment, but not shown in the present embodiment) at equal intervals and in parallel with the pin fitting 8 in the cap portion 5a. It is formed so as to penetrate 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 inserted in series. A high-strength heat-resistant insulating tube 10 is formed in a cylindrical shape on the outer peripheral side of the current limiting element 9 with a predetermined gap, and made of a high-strength heat-resistant insulating material such as fiber reinforced resin, silicon nitride or partially stabilized zirconia. Covered with the through hole 5e
A heat-resistant elastic insulating material 11 made of silicon rubber is filled so as to embed the high-strength heat-resistant insulating cylinder 10 between the inner peripheral surface of the current limiting element 9 and the outer peripheral surface of the current limiting element 9.

Cap-shaped upper electrodes are provided on both upper and lower ends of the mounting cylinder 5d.
12 and the lower electrode 13 are fitted via the solder 14, and the mounting cylinder portion
The upper and lower ends of 5d are crimped.

Metallized layers 15 are provided on the upper and lower end surfaces of the current limiting element 9 by metallikon, silver baking, or another method. On the surface of the metallized layer 15, a metal-made thin protective plate 16 for conduction is provided. A pressure spring 17 having electrical conductivity and heat conductivity is interposed between the conduction protection plate 16 and the upper and lower electrodes 12 and 13 to electrically connect the current limiting element 9 to the upper electrode 11 and the lower electrode 12. I am trying to do it. Further, the rubber-like adhesive elastic body 18 is enclosed in the inner space of the upper and lower electrodes 12, 13 to improve the airtightness by increasing the adhesive sealing surface.

One ends of lead wires 19 and 20 are adhesively fixed to the upper surface of the upper electrode 12 and the lower surface of the lower electrode 13, and the other end of the upper lead wire 19 is connected to the cap fitting 7 and the lower lead wire 20 is connected.
The other end of is connected to the pin fitting 8.

Next, the operation of the lightning protection insulator configured as described above will be described.

When an excessive voltage of 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 arrester 3 on the lowermost side, and the lead wire 20 → lower electrode 13 → pressing spring. 17 →
Conduction protection plate 16 → Metallized layer 15 → Current limiting element 9 → Metallized layer 15 → Conduction protection plate 16 → Pressing spring 17 → Upper electrode 12 →
The lead wire 19 is transmitted to the cap fitting 7. afterwards,
From the cap metal fitting 7 to the pin metal fitting 8 of the lightning protection insulator 3 directly above.
Transmitted to. Similarly, a plurality of lightning protection insulators 3 connected in series
Is transmitted to the ground from the cap metal fitting 7 of the uppermost lightning protection insulator 3 through the hanging metal fitting 2 and the support arm 1.

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.

In the embodiment of the present invention, even if the current limiting element 9 becomes conductive due to an unexpected lightning strike and a high-temperature, high-pressure arc is generated in the current limiting element 9 due to the continuous current, expansion and pressure due to arc heat are High-strength heat-resistant insulating cylinder 10 that is absorbed by the heat-resistant elastic insulating material 11 and has high strength heat resistance
Absorbs the mechanical force, and the heat-resistant elastic insulating material 11 filled between the high-strength heat-resistant insulating cylinder 10 and the through hole 5e absorbs the expansion of the high-strength heat-resistant insulating cylinder 10. Almost no mechanical force acts on the through hole, and it is possible to prevent cracks from entering the through hole 5e, damage to the cap portion 5a and damage to the insulator main body 5 due to it, and disconnection of the power transmission line L is prevented. Can improve the reliability.

The present invention is not limited to the above embodiment,
It may be embodied as follows.

(1) Although not shown, an inner high-strength heat-resistant insulating cylinder made of fiber reinforced resin, which is located inside the high-strength heat-resistant insulating cylinder 10, and an outer high-strength heat resistance made of silicon nitride fitted on the outer side thereof Consists of an insulating cylinder. In this another example, the outer high-strength heat-resistant insulating cylinder made of silicon nitride, which is weak against impact, protects the inner high-strength heat-resistant insulating cylinder, so that the strength is improved as compared with the case where silicon nitride is provided alone.

(2) Arranging two, three, or five or more current limiting elements 9 at equal angles.

(3) To form the mounting tube portion 5d as a separate body or to be flush with the upper surface of the cap portion 5a.

Effects of the Invention As described in detail above, the present invention prevents the insulator main body from being damaged due to the generation of high-temperature / high-voltage arcs in the current-limiting element portion when the current-limiting element is abnormal, and disconnects the power transmission line. Can be suppressed and the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a partial vertical cross-sectional view showing a main part of a lightning protection insulator showing an embodiment of the present invention, FIG. 2 is a semi-longitudinal cross-sectional view showing a current limiting element, and FIG. 3 is a front view showing a usage state of the lightning protection insulator. It is a figure. 3 ... Lightning protection insulator, 5 ... Insulator main body, 5a ... Head portion, 5c ... Head portion, 5d
… Mounting cylinder, 5e… Through hole, 7… Cap fitting, 8… Pin fitting, 9… Current limiting element, 10… High-strength heat-resistant insulating cylinder, 11… Heat-resistant elastic insulating material, 12,13… Top, bottom Electrodes, 19, 20 ... Lead wires.

Claims (4)

[Claims] 1. A cap metal fitting (7) is capped and fixed to a capped tubular head (5c) formed in the central upper part of a cap portion (5a) of an insulator body (5), and the inside of the head (5c) is fixed. A pin metal fitting (8) is fitted and fixed in the through hole (5e) in the cap portion (5a), and a current limiting element (9) having a non-linear voltage-current characteristic is provided in the through hole (5e). ) Is inserted, and the outer peripheral side of the current limiting element (9) is covered with a high-strength heat-resistant insulating cylinder (10) having high strength and heat resistance with a predetermined gap, and the inner peripheral surface of the through hole (5e). And the high-strength heat-resistant insulating cylinder (10) between the outer peripheral surface of the current limiting element (9) and
A lightning protection insulator characterized by being filled with a heat resistant elastic insulating material (11) so as to be embedded therein, and further provided with an upper electrode (12) and a lower electrode (13) at both upper and lower ends of the through hole (5e). . 2. The lightning protection insulator according to claim 1, wherein the high-strength heat-resistant insulating cylinder (10) is made of fiber reinforced resin, silicon nitride or partially stabilized zirconia. 3. The high-strength heat-resistant insulating cylinder (10) comprises an inner high-strength heat-resistant insulating cylinder made of fiber reinforced resin and an outer high-strength made of silicon nitride or partially stabilized zirconia fitted and fixed on the outside thereof. The lightning protection insulator according to claim 1, which is formed of a heat-resistant insulating cylinder. 4. The lightning protection insulator according to claim 1, wherein the heat-resistant elastic insulating material (11) is silicon rubber.