JPH01166421A - Pressure-resistant insulating tube for lightning insulator - Google Patents

Abstract

PURPOSE:To realize a small thickness of a pressure-resisting insulating tube and a small size of a lightning insulator by forming pressure discharge slits to the pressure-resisting insulating tube. CONSTITUTION:At the top periphery of a cylindrical weather-proof pressure- resisting insulating tube 1 which consists of a pressure-resisting reinforced resin, an electrode metal 3 at the earthing side is geared and fixed with an adhesive 2. At the inner surface of the pressure-resisting insulating tube 1, slits 1a for pressure discharge purpose are formed at plural positions in the longitudinal direction parallel each other and at equal intervals, preventing the linking in the radius direction each other. These slits 1a are formed up to near electrode metals 3 and 4 shown in the figure. As a result, even when the arc in a high temperature and a high voltage is generated, the arc in the pressure-resisting insulating tube 1 is discharged to the outside, and the rise of the pressure inside the pressure-resisting tube 1 can be reduced. Consequently, the thickness of the pressure-resisting insulating tube 1 can be reduced, and a compact size of lightning insulator can be realized accordingly.

Description

[Detailed Description of the Invention] Purpose of the Invention (Field of Industrial Application) The present invention promptly discharges lightning surge current to the ground when it flows through a power transmission line or distribution line, and also discharges the subsequent commercial frequency continuation. The present invention relates to a voltage-resistant insulating tube applied to a lightning arrester that can suppress and interrupt flowing current.

(Problems to be solved by the prior art and the invention) As shown in FIG. 7, as a conventional lightning arrester, an annular current-limiting element 32 is fitted to a tension 4@edge bar 31. Cap fittings 33 and 34 are disposed at both ends of the tensile insulating rod 31, and the current limiting element 32 is inserted between the cap fittings 33 and 34 with an elastic body 35.
There is a structure in which the current limiting element 32 is kept under zero bullet and the outer periphery of the current limiting element 32 is covered with an organic insulating jacket 36 made of porcelain or epoxy resin to hermetically encapsulate the current limiting element 32.

However, in the above-mentioned lightning arrester, since the jacket body 36 is made of porcelain or epoxy resin, when the current-limiting element 32 becomes conductive and a high-temperature, high-pressure arc is generated, it is used as a means for releasing the pressure. It is necessary to provide the mantle 36 with a rupture disc that ruptures under a certain pressure, which causes the problem that manufacturing thereof is troublesome.

In order to solve this problem, the applicant of the present application proposed a lightning arrester shown in FIG. In this lightning arrester, cap metal fittings 38 and 39 are fitted and fixed to the openings at both ends of a cylindrical voltage-resistant insulating tube 37, and a current-limiting element 32 is accommodated in the voltage-resistant insulating tube 37. 38 and 39, and at least one pressure relief hole 37ajc is provided in the voltage-resistant insulating cylinder 37 so as to correspond to both ends of the current-limiting element 32.
The cap metal fittings 38 and 39 are provided with arc inviting members 40 corresponding to the outside of the pressure relief hole 37a, and the outer periphery of the voltage-resistant insulating cylinder 37 and the voltage-resistant insulating cylinder 37 and the current limiting element are provided. A lightning arrester is provided in which the gap between the lightning arrester 32 and the lightning arrester 32 is molded with an organic insulating material 41 made of rubber.

However, since this lightning arrester has a plurality of circular pressure relief holes 37a formed in the voltage-resistant insulating cylinder 37, if the current-limiting element 32 becomes conductive for some reason, the high temperature A high-voltage arc is generated, and as a result, the internal pressure of the voltage-resistant insulating cylinder 37 increases, so it is necessary to withstand this, and the voltage-resistant insulating cylinder 37 must be made thicker to compensate for this, resulting in an increase in the size of the lightning arrester.

Further, when attempting to provide a plurality of pressure relief ports 37a at regular positions, there is a problem in that processing is labor-intensive and costs are high.

It is an object of the present invention to solve the problems existing in the above-mentioned conventional technology, and to solve the problem that a voltage-resistant insulating tube is incorporated into a lightning arrester in the event that an unexpected lightning surge current enters the lightning arrester or due to other causes. When the current-limiting element becomes conductive, the high-temperature, high-pressure arc is quickly discharged to the outside through a slit in the voltage-resistant insulating tube to reduce the internal pressure acting on the voltage-resistant insulating tube. The insulation cylinder can be made thinner,
Another object of the present invention is to provide a voltage-resistant insulating tube that can reduce the size and cost of a lightning arrester.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention takes a measure of forming a pressure relief slit in the voltage-resistant insulating tube.

(Function) In the present invention, since a pressure relief slit is formed in the voltage-resistant insulating cylinder, when the voltage-resistant insulating cylinder is assembled into the lightning arrester,
If a lightning surge current that exceeds expectations flows through a current-limiting element, or if the current-limiting element becomes conductive due to other causes, a high-temperature, high-pressure arc will occur. In such a case, if the slit penetrates the FPR cylinder in the radial direction with a certain width, if the current applied during pressure release is small, it will flow directly to the outside of the slit, and if it is large, it will destroy a part of the FRP cylinder and the slit will open. The width is widened and the pressure is released to the outside. Moreover, if it does not penetrate, it is broken so as to penetrate the slit of the FRP cylinder and the pressure is released to the outside. In both cases FR
Although a part of the P cylinder is destroyed, the damage is the minimum necessary for pressure relief, and there is no problem because the subsequent bending and tensile strength, etc., can exhibit sufficient values for practical use.

Since the arc is quickly released to the outside, the pressure applied to the voltage-resistant insulation tube is also reduced, making it possible to reduce the wall thickness of the insulation tube, which in turn leads to downsizing and cost reduction of the lightning arrester. It can be measured.

Furthermore, by forming slits in the longitudinal direction of the voltage-resistant insulating tube, the width of the cutout in the FRP tube can be made smaller, so that mechanical strength such as bending and tensile strength can be improved.

(Example) Hereinafter, an example embodying the present invention will be described based on FIGS. 1 to 5.

A ground side electrode fitting 3 is fitted and fixed to the upper end outer circumference of a cylindrical, weather-resistant, pressure-resistant insulating cylinder 1 made of reinforced resin (for example, FRP), and the outer circumferential surface of the electrode fitting 3 is fixed with an adhesive 2. A flange portion 3a is integrally formed to be attached to a mounting adapter attached to a support arm of a steel tower (not shown). Further, an adhesive 2 is applied to the outer peripheral surface of the lower end of the voltage-resistant insulating cylinder 1.
A bottomed cylindrical electrode fitting 4 on the power supply side is hermetically fitted and fixed, and although not shown in the figure, the electrode fitting 4 on the power supply side attached to the power transmission line side has a predetermined connection with the arc horn on the power supply side attached to the power transmission line side. A bracket 4a for mounting the arc horn on the ground side facing each other with an air discharge gap is integrally formed.

A fitting cylindrical portion 4b is formed on the inner bottom surface of the electrode fitting 4 on the energizing side, and a lower end portion of the conductor fitting 5 on the energizing side is fitted and fixed to this. On the upper surface of the conductor and metal fitting 5, a current limiting element 6 mainly made of zinc oxide, which has non-linear voltage-current characteristics, is stacked in series. Ground side conductor metal fitting 7 that has a cylindrical bottom shape and also serves as a spring holder
is supported.

On the other hand, a tightening ring 8 is screwed into a threaded portion 3b formed on the inner peripheral surface of the electrode fitting 3 on the ground side, and between the intermediate conductor 9 fitted in the ring 8 and the conductor fitting 7. A coiled spring 11 having a shunt 10 for energization is interposed. This spring 11 presses and fixes the current limiting element 6 between the conductive metal fitting 5 on the power supply side and the conductive metal fitting 7 on the grounding side.

Further, on the inner circumferential surface of the voltage-resistant insulating tube 1, a plurality of pressure relief slits la are formed in the elongated direction at a plurality of locations parallel to each other and spaced at equal intervals so as not to penetrate in the radial direction. This slit 1a is connected to the electrode fitting 3 as shown in FIG.
．． It is formed up to around 4. Then, the slit 1
The thin wall portion 1b on the outer circumferential side of the voltage-resistant insulating cylinder 1 corresponding to a is set to be thinner when the internal diameter of the voltage-resistant insulating cylinder 1 is small, and thicker when it is thicker. It is preferable to determine the absolute value of the thickness based on the strength of the applied material in coordination with the thickness of the portion without slits, in order to promote the opening-breaking effect during pressure release, which will be described later.

Additionally, an insulating jacket 12 made of, for example, rubber and having a large number of insulating pleats 12a is hermetically molded on the outer peripheral surface of the voltage-resistant insulating cylinder 1. This insulating jacket 12 extends to the outer peripheral surface of the electrode fittings 3, 4, and
It is designed to improve airtightness. Furthermore, at the same time as the insulating jacket 12 is molded, a wA edge sealing body 13 for sealing the opening of the electrode fitting 3 on the ground side is molded.

A gas filling hole 4C is formed in the electrode fitting 4, and nitrogen gas or sulfur hexafluoride ( A gas having excellent insulating properties such as SF6) is sealed, and after being sealed, it is sealed with a seal plug 14. Note that since the pressure of this gas is normal pressure, it has almost no effect on the insulating jacket 12, 13.

A deflection regulating ring 15 made of glass, aramid fiber, steel, or the like is embedded approximately in the center of the insulating jacket 12 at a predetermined distance from the outer peripheral surface of the voltage-resistant insulating cylinder 1. This ring 15 prevents further deformation of the voltage-resistant insulating cylinder 1 or the insulating jacket 12 even if the pressure-resistant insulating cylinder 1 expands radially outward during pressure release, as shown by the chain line in FIG. We try to keep destruction to a minimum.

Next, the operation of the lightning arrester constructed as described above will be explained.

Now, when a lightning surge current flows through a power transmission line with a lightning arrester attached to a steel tower, the current flange-overs from the arc horn on the power transmission line side (as shown) to the arc horn at the lower end of the lightning arrester (as shown). , the electrode fitting 4 on the charging side, the conductive fitting 5, the current limiting element 6, the conductor fitting 7, the shunt 10, the intermediate conductor 9 and the tightening ring 8, and then the electrode fitting 3 on the grounding side.
It then flows to the steel tower via a mounting adapter (not shown) and is discharged to the ground.

Furthermore, subsequent currents that occur thereafter are suppressed and blocked by both arc horns and the current limiting element 6.

Now, in the embodiment of the present invention, a slit 1a is provided on the inner circumferential surface of the voltage-resistant insulating cylinder l, so that in the unlikely event that an unexpectedly large-scale lightning surge current is applied to the current-limiting element 6, Even if the current limiting element 6 becomes conductive and a high-temperature, high-pressure arc is generated, the arc immediately acts on the slit 7) la of the voltage-resistant insulating cylinder 1 and damages the thin-walled portion 1b and the thin-walled portion 1b. While melting and breaking the insulating jacket 12 corresponding to the slit 1a, the slit 1a is instantaneously expanded in diameter in the circumferential direction and opened. As a result, the arc inside the voltage-resistant insulating tube 1 is released to the outside, reducing the pressure rise inside the voltage-resistant insulating tube 1, making it possible to reduce the wall thickness of the voltage-resistant insulating tube 1, and ultimately making the lightning arrester smaller. Since it is easy to convert and process, costs can be reduced.

In addition, in the embodiment of the present invention, since the pressure relief slit 1a is formed in the longitudinal direction of the voltage-resistant insulating tube 1, the notch width is also small.
Therefore, mechanical strength can be improved.

Note that the present invention can also be embodied in the following manner.

(1) A thin wall portion is provided in the insulating jacket 12 corresponding to the slit.

(2) In the above embodiment, the slit 1a was formed so as not to penetrate the voltage-resistant insulating tube l, but as shown in FIG. to do. In this other example, airtightness is maintained only by the insulating jacket 12.

(3) In the above embodiment, the closed space R was filled with an insulating gas, but instead of this, an insulating filler such as EPDM or silicone rubber may be filled.

(4) In the above embodiment, the slit 1a was provided on the inner circumferential surface of the voltage-resistant insulating cylinder 1, but it may be provided on the outer circumferential surface or on both the inner and outer wall surfaces.

(5) In the above embodiment, an insulating gas was filled in the pressure-resistant insulating cylinder, but instead of this, an insulating filler such as EPDM or silicone rubber may be filled.

Although not directly related to the present invention, it is also conceivable to form a non-penetrating slit in the lightning arrester bag in which the voltage-resistant insulating cylinder 1 is omitted and the current limiting element 6 is covered with a resin porcelain tube.

Effects of the Invention As described in detail above, the present invention has the effect of making it possible to reduce the thickness of the voltage-resistant insulating cylinder, ensure mechanical strength, and further reduce the size of the lightning arrester.

[Brief explanation of the drawing]

FIG. 1 is a partial perspective view of a voltage-resistant insulating tube, FIG. 2 is a half-longitudinal sectional view showing an embodiment of a lightning arrester incorporating the voltage-resistant insulating tube of the present invention, and FIG. 3 is a line taken along line A-A in FIG. 2. Cross-sectional view, Figure 4 is the second
5 is a sectional view taken along line C-C in FIG. 2, FIG. 6 is a partial sectional view showing another example of the present invention, and FIGS. FIG. 2 is a longitudinal cross-sectional view showing a lightning arrester. 1...Voltage-proof insulation tube, 1a...Slit, 1b...
Thin wall part, 3... Electrode fitting on the grounding side, 4... Electrode fitting on the charging side, 5... Conductive fitting, 6... Current limiting element, 7.
... Conductor metal fitting, 8... Tightening ring, 9... Intermediate conductor, 10... Shunt, 11... Spring, 12... Insulating jacket, 13... Insulating sealing body, 14...・Tight stopper, 1
5...Restriction ring, R...Closed space.

Claims (1)

[Claims] 1. A voltage-resistant insulating cylinder for a lightning arrester, characterized in that a slit for pressure relief is formed. 2. The lightning arrester according to claim 1, wherein a plurality of slits are formed parallel to each other in the longitudinal direction of the inner peripheral surface of the voltage-resistant insulating cylinder and do not penetrate the voltage-resistant insulating cylinder. A pressure-resistant insulating cylinder for use.