JPH0324042B2 - - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) This invention relates to a lightning arrester having a built-in lightning arrester element and particularly used in an insulator device for an overhead power transmission line. The present invention relates to a reinforcing structure for a voltage-resistant insulating cylinder provided with holes.

(Prior art) Conventionally, as a lightning arrester insulator with a built-in lightning arrester,
A cylindrical grounding side electrode and a cylindrical energizing side electrode are fitted and fixed to the upper and lower ends of a voltage-resistant insulating tube with excellent mechanical strength such as FRP, and a lightning arrester with non-linear voltage-current characteristics is installed between the two electrodes. A rubber mold is provided between the lightning arrester element and the voltage-resistant insulating tube and on the outer periphery of the voltage-resistant insulating tube, and a rubber mold is provided on the outer periphery of the voltage-resistant insulating tube to prevent the lightning arrester from abnormally discharging due to an unexpected large-scale lightning strike. It has been proposed that pressure relief holes be formed to release the high temperature and high pressure arc generated by the insulator to the outside of the insulator.

(Problem to be solved by the invention) However, in the special case of an effective grounding system where the short circuit current is extremely large, or an ineffective grounding system, it is necessary to consider a short circuit current of tens of thousands of amperes.
FRP voltage-resistant insulation tube alone is not strong enough. In other words, stress concentration on the edge of the pressure relief hole due to arc discharge during the above-mentioned large-scale lightning strike causes cracks to occur in the voltage-resistant insulating tube, and these cracks propagate in the longitudinal direction, causing the voltage-resistant insulating tube to break. However, there are problems such as the need to significantly increase the wall thickness in order to obtain the required strength.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention includes a cylindrical ground side electrode 12 and a voltage-applied electrode at the upper and lower ends of the voltage-resistant insulating cylinder 11 in which the pressure relief hole 11a is formed. Side electrode 13
At the same time, a lightning arrester element 16 with non-linear voltage-current characteristics is housed and fixed between both electrodes 12 and 13, and a lightning arrester element 16 with non-linear voltage-current characteristics is fitted and fixed, and a In the lightning arrester provided with the rubber mold 26, a reinforcing ring 25 made of a pressure-resistant material is provided on the outer periphery of the pressure-resistant insulating cylinder 11 so as not to cover the pressure relief hole 11a.

(Function) Since the present invention employs the above means, stress concentration occurs at the edge of the pressure release hole when pressure is released from a high-temperature, high-pressure arc caused by abnormal discharge of the lightning arrester element due to an unexpected large-scale lightning strike, resulting in voltage-resistant insulation. Even if the tube cracks,
A reinforcing ring provided around the outer periphery of the pressure-resistant insulating cylinder improves its strength and bears the pressure inside the insulating cylinder. This prevents cracks from progressing in the longitudinal direction of the voltage-resistant insulating cylinder. In addition, in order to obtain the required pressure resistance, a reinforcing ring is provided around the outer periphery of the pressure-resistant insulating tube, so the thickness of the insulating tube can be reduced and the weight of the lightning arrester can be significantly reduced. Stress concentration on the hanging fittings during vibration is prevented.

(Example) Hereinafter, an example embodying this invention will be described in the first to
This will be explained according to FIG. As shown in FIG. 2, hanging insulators 3, 3 are rotatably suspended from both left and right ends of the ground-side hanging fitting 2 attached to the tower body 13. A wire-side hanging fitting 4 having a discharge electrode 5 in the center is attached to the lower end, and an electric wire 7 is suspended and supported from the hanging fitting 4 via a clamp 6. Further, a lightning arrester 10 is attached to a bracket 8 attached to the center of the hanging fitting 2.

Next, to explain the lightning arrester 10, as shown in FIGS. 1 and 3, the upper end of the voltage-resistant insulating cylinder 11 is made of a material such as reinforced plastic (FRP) that has excellent mechanical strength, heat resistance, and pressure resistance. A cylindrical ground side electrode 12 having a stepped portion 12a on the inner surface and a mounting flange 12b on the upper outer periphery is fitted and bonded, and a cylindrical engagement tube 13a is protruded from the lower end toward the center of the bottom. A bottomed cylindrical power supply side electrode 13 is provided.
are fitted and glued. A discharge electrode 14 is attached to a mounting piece 13b provided on the lower surface of the energized side electrode 13, and an air discharge gap G is formed between it and the discharge electrode 5 provided on the hanging metal fitting 4, as shown in FIG. is forming.

As shown in FIG. 3, an element assembly 15 is accommodated within the voltage-resistant insulating cylinder 11. This element assembly 1
5 has a plurality of lightning arrester elements 16 which are mainly made of zinc oxide (ZnO) and has non-linear voltage-current characteristics stacked in series, and upper and lower element holding fittings 17 and 18 are attached to the lightning arrester elements 16 at both the upper and lower ends, respectively. join,
A coating 19 made of EPDM rubber is provided around the outer periphery of the lightning arrester element 16 and both element holding fittings 17 and 18. The lower end of the element assembly 15 is
A protrusion 18a formed on the lower element holding fitting 18 is engaged with the engagement tube 13a of the power-supplying electrode 13 to regulate its position.

As shown in FIG. 3, a fastening fitting 20 having a male thread 20a on the outer circumferential surface is screwed into a female thread 12c formed on the inner circumferential surface of the ground side electrode 12.
A terminal fitting 22 is fixed through the insertion hole 20b at the center of the tightening fitting 20 via a cylindrical insulating spacer 21, and the element assembly 15 is inserted between it and the element holding fitting 17 on the upper part of the element assembly 15. A spring 23 is interposed between the terminal fitting 22 and the voltage-applying side electrode 13, which is crimped and fixed and applies contact pressure to the lightning arrester element 16. Note that a plurality of shunts 24 (three in this embodiment) are interposed in the spring 23 to improve electrical connection.

Pressure relief holes 11a are formed in the upper part, two middle parts, and the lower part of the voltage-resistant insulating cylinder 11 at intervals of 90 degrees in the diameter direction (see FIG. 4) for releasing arcs in the event of an abnormality. The length L of the pressure relief hole 11a is the width S
The distance between the pressure relief holes 11a in the vertical direction is preferably within 6 times the inner diameter of the voltage-resistant insulating cylinder 11. Further, by providing the pressure release hole 11a in the vicinity of the grounding side electrode 12 and the energizing side electrode 13 and in the intermediate portion thereof, the arc can be emitted efficiently. Moreover, as shown in FIG.
An annular reinforcing ring 25 made of reinforced plastic (FRP) is attached to the upper and lower intermediate portions of each pressure release hole 11a on the outer peripheral surface of the pressure release hole 11a using a heat-resistant resin adhesive (not shown).
It is fixed with adhesive.

A rubber mold 26 made of EPDM rubber is formed between the voltage-resistant insulation cylinder 11 and the element assembly 15, between the ground side electrode 12 and the terminal fitting 22, and on the outside of the voltage-resistant insulation cylinder 11. It extends to the lower outer circumferential surface and the upper outer circumferential surface of the energizing side electrode 13, and pleats 26a are integrally formed on the outer circumference.

Further, as shown in FIG. 4, the rubber mold 26 is provided with a pressure release port 26b at a position corresponding to the pressure release hole 11a of the voltage-resistant insulating cylinder 11.

As shown in FIG. 2, an arcing ring 28 is provided on one side of the bracket 8 via an arcing ring arm (not shown) so as to correspond to the upper pressure release port 26b. On the other hand, the lower pressure relief port 26 is also connected to the mounting piece 13b of the energized side electrode 13 via an arcing ring arm (not shown).
An arcing ring 28 is provided to approximately correspond to b.

Next, the operation of the insulator device constructed as described above will be explained.

Now, when a lightning surge enters the wire 7 due to a lightning strike, the current flows from the wire 7 to the clamp 6 → the hanging metal fitting 4 →
An arc is discharged from the discharge electrode 5 to the discharge electrode 14 of the lightning protection insulator 10 through the air discharge gap G, flows from the energized side electrode 13 to the lightning arrester element 16 via the lower element holding metal fitting 18, and further flows to the upper element holding metal fitting. 17→
It flows from the tower body 1 to the earth via the shunt 24 → terminal fitting 22 → hanging fitting 2. The subsequent current caused by this is blocked by the lightning arrester element 16.

In addition, lightning arrester 1 was damaged due to an unexpected large-scale lightning strike.
6 is abnormally discharged and a high-temperature, high-pressure arc occurs, the coating 1 near the pressure relief hole 11a of the voltage-resistant insulating cylinder 11
9 and a portion of the rubber mold 26 are softened or melted and destroyed, and are blown away by the high-pressure gas, to forcibly form an arc discharge path leading to the outside.

Even if stress concentration occurs at the edge of the pressure relief hole 11a due to this arc and cracks occur in the pressure-resistant insulating tube 11, the strength is improved by the reinforcing ring 25 adhesively fixed to the outer periphery of the pressure-resistant insulating tube 11. 11 internal pressures are borne. Therefore, cracking and destruction in the longitudinal direction of the voltage-resistant insulating cylinder 11 are prevented.

In addition, when obtaining the required pressure-resistant strength, the pressure-resistant insulation cylinder 1
Since the reinforcing ring 25 is provided on the outer periphery of the lightning arrester 10, the thickness of the insulating cylinder 11 can be reduced to make the lightning arrester 10 smaller and lighter.

The arc emitted to the outside of the lightning arrester 10 is transferred between both arcing rings 28, and the upper and lower sides are connected to each other.

Note that this invention may be implemented as follows.

(1) The voltage-resistant insulating tube 11 and the reinforcing ring 25 are integrally formed as shown in FIGS. 7a to 7d. In this case, first, as shown in figure a, the mandrel 2
After the glass fiber cloth 30 is cross-wound around the outer peripheral surface of the cross-section 9, glass fibers 31 are wound along the circumference at predetermined intervals as shown in FIG. Then, as shown in FIG.
be penetrated.

(2) As shown in FIG. 8, a plurality of reinforcing rings 25 are provided between each pressure relief hole 11a.

(3) As shown in FIG. 9, the inner diameter of the reinforcing ring 25 is made larger than the outer diameter of the voltage-resistant insulating cylinder 11 so that a slight gap is created between the reinforcing ring 25 and the voltage-resistant insulating cylinder 11, When forming the rubber mold 26, the gap is filled with rubber and fixed. In this way, the internal pressure impact force at the time of pressure release can be alleviated.

(4) Fix the reinforcing ring 25 with a pin.

(5) The reinforcing ring 25 is made of metal.

Effects of the Invention As detailed above, in this invention, a reinforcing ring is provided on the outer periphery of the voltage-resistant insulating cylinder so that it does not touch the pressure release hole, so that the lightning arrester element is prevented from abnormally discharging due to an unexpected large-scale lightning strike. Even if stress concentration occurs at the edge of the pressure relief hole during pressure release of a high-temperature, high-pressure arc and cracks occur in the pressure-resistant insulating tube, the reinforcing ring will bear this release pressure and prevent the pressure-resistant insulating tube from extending in the longitudinal direction. This has the excellent effect of preventing the progression of cracks, improving the strength of the voltage-resistant insulating cylinder, and reducing the thickness of the voltage-resistant insulating cylinder to reduce the size and weight of the lightning arrester.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a front view showing an insulator device equipped with a lightning arrester, FIG. 3 is a longitudinal sectional view of the lightning arrester, and FIG.
The figure is an end view taken along the line A-A of FIG. 3, FIG. 5 is an end view taken along the line B-B of FIG. 3, FIG. 6 is an end view taken along the line CC of FIG. 3, and FIGS. An explanatory diagram showing the manufacturing process of another example of the reinforcing ring, FIG. 7 d is a partially enlarged sectional view of the reinforcing ring, FIG. 8 is a front view showing another example, and FIG. 9 is a partial sectional view showing another example. . 11...Voltage insulating cylinder, 11a...Pressure release hole, 12
...Grounding side electrode, 13...Powering side electrode, 26...
Lightning arrester element, 25... Reinforcement ring, 26... Rubber mold.

Claims (1)

[Claims] 1. A cylindrical ground side electrode 12 and a cylindrical energized side electrode 13 are fitted and fixed to the upper and lower ends of a voltage-resistant insulating cylinder 11 in which a pressure relief hole 11a is formed, respectively, and both electrodes 1
In the lightning arrester insulator, a lightning arrester element 16 having non-linear voltage-current characteristics is housed and fixed between 2 and 13, and a rubber mold 26 is provided between the lightning arrester element 16 and the voltage-resistant insulating cylinder 11 and on the outer periphery of the voltage-resistant insulating cylinder 11. A reinforcing structure for a voltage-resistant insulating cylinder in a lightning arrester, characterized in that a reinforcing ring 25 made of a pressure-resistant material is provided on the outer periphery of the voltage-resistant insulating cylinder 11 so as not to cover the pressure relief hole 11a. 2. A reinforcing structure for a voltage-resistant insulating cylinder in a lightning arrester according to claim 1, wherein the voltage-resistant insulating cylinder 11 and the reinforcing ring 25 are made of reinforced plastic and are provided separately. 3 The pressure-resistant insulating cylinder 11 and the reinforcing ring 25 are made of glass fiber 3 on the outside of a glass fiber cloth 30 wound into a cylindrical shape.
1 is wrapped around glass fiber cloth 30 and glass fiber 3
1. A reinforcing structure for a voltage-resistant insulating cylinder in a lightning arrester according to claim 1, which is integrally provided by impregnating a resin into a lightning arrester. 4. A reinforcing structure for a voltage-resistant insulating tube in a lightning arrester according to claim 1, wherein the reinforcing ring 25 is made of metal.