JP3175244B2 - Transmission line lightning arrester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance laminated body formed by stacking disk-shaped non-linear resistance elements in a column shape in an insulation tube, and fixed to both ends of the insulation tube via springs to connect with an external conductor. The present invention relates to a transmission line lightning arrester having a structure held between connected current electrodes.

[0002]

2. Description of the Related Art FIG. 3 shows the structure of a lightning arrester disclosed in Japanese Patent Application Laid-Open No. 1-176687 as a first example of a conventional lightning arrester of this type. The insulating cylinder 22 that houses the resistance laminated body formed by stacking the disc-shaped non-linear resistance elements 1 mainly composed of zinc oxide in a column shape is made of FRP (glass-filled synthetic resin molded with increased mechanical strength). The resistance laminated body is held via a spring 24 between current electrodes 23 and 33 which are fixed to both ends of the insulating cylinder 22 using an adhesive or a pin, respectively. The upper current electrode 23 has a central pedestal 2 having a contact surface with a spring 24.
3d, a cylindrical portion 23e coaxially surrounding the pedestal portion 23d with a gap, and a flange portion 23f abutting on the upper end surface of the insulating tube 22.
3c is formed. The lower current terminal 33 is
Central pedestal 3 having a contact surface with the lower end surface of the resistance laminate
3d, a cylindrical portion 33e coaxially surrounding the pedestal portion 33d with a gap, and a flange portion 33f abutting on the lower end surface of the insulating tube 22.
3c is formed. The pressure release holes 23c and 33c cover the entire outer peripheral surface of the insulating cylinder 22 and form a heat-shrinkable organic elastic insulating material (hereinafter referred to as an organic insulating material) forming a ring-shaped fold 25a.
It is closed by 25.

When the lightning energy to be absorbed by the lightning arrester exceeds the energy withstand capability of the lightning arrester during a lightning strike, the non-linear resistance element 1 is thermally destroyed, an arc is generated in the insulating cylinder 22 and the pressure in the cylinder is reduced. To rise. When this pressure exceeds a predetermined value, the organic insulating material covering the pressure release holes 23c and 33c is broken, and the gas in the insulating cylinder 22 is displaced by the pedestals 23d and 33d at the center of the current electrodes 23 and 33 and the cylindrical portion 23e. Through the cylindrical flow path formed between the pressure release holes 23c and 33e.
c to the outside air, the pressure in the cylinder falls below a predetermined value,
The insulating cylinder 22 is prevented from bursting, and the resistance element 1 and the spring 24 are prevented from scattering. The reference numerals 26 and 27 in the drawing denote high-temperature ionized gas discharged from the pressure release holes 23c and 33c to the outside air in the longitudinal direction of the insulating cylinder 22 to the outside of the insulating cylinder 22 for the arc flash path. And an arc guide for shifting the arc inside the insulating cylinder to the outside to reduce the pressure inside the insulating cylinder.

FIG. 4 shows a second conventional example of this type of lightning arrester structure. In the figure, an insulating cylinder 4 is formed by covering the entire outer peripheral surface of a cylindrical body made of FRP with a heat-shrinkable organic insulating material and integrally forming a ring-shaped fold made of the insulating material. An upper current electrode 8 is fixed together with an arc guide 26 using a nut 9 to a flange 7 fixed to the upper end using an adhesive or a pin. Further, the lower current electrode 2 includes a central pedestal portion 2d for supporting a columnar resistance laminated body made of the resistance element 1, and a flange portion 2f for maintaining airtightness between the insulating cylinder 4 and the pin 5. And is fixed to the lower end of the insulating tube 4. In the current electrode 2, a pressure release passage 3 is formed by a horizontal hole of the pedestal portion 2d, a vertical hole extending from the pedestal portion 2d to the flange portion 2f, and a horizontal hole of the flange portion 2f. The pressure-release end of the pressure-release path 3 is air-tightly covered by heating the insulating tube 6 made of a heat-shrinkable organic insulating material over the insulating tube 4 and the current electrode 2. When a lightning strike causes an arc in the insulating cylinder 4 and the in-cylinder pressure exceeds a predetermined value, the gas in the insulating cylinder 4 passes through the pressure release path 3, covers the insulating tube 6, and is discharged to the outside air. 4 to prevent rupture.

[0005] As a third conventional example of this type of lightning arrester, the structure of Japanese Patent Laid-Open No. 62-133701 is shown in FIG.
Shown in The figure shows the lower half of the lightning arrester,
In this example, an insulating tube 28 made of FRP is
The current terminal 30 is fixed to the lower end of the insulating cylinder 4 by using a pin 29. The current electrode 30 has a pedestal portion 30a at the center, and the resistance element 1
And a plurality of pressure release holes 31 around the central axis.

When a lightning strike causes an arc in the insulating cylinder 28 and the in-cylinder pressure exceeds a predetermined value, the gas sealed in the insulating cylinder 4 breaks the pressure relief plate 32 and is discharged from the pressure relief port 38 to the outside air. Is done. If the pressure release from the pressure release port 38 alone is insufficient, the second pressure release plate 35 will burst, and the gas will also be discharged downward. Reference numeral 40 in the drawing denotes packing, which prevents high-temperature, high-pressure ionized gas in the cylinder from entering the gap between the insulating cylinder 28 and the insulator tube 27 when the pressure in the cylinder increases due to arcing. This is to prevent the porcelain tube from exploding due to arc flash in the gap.

[0007]

When lightning strikes, the lightning energy exceeds the energy withstand capability of the lightning arrester and the non-linear resistance element causes thermal destruction, an arc is generated in the insulating cylinder and the gas pressure in the cylinder reaches a predetermined value. When it exceeds, the gas in the insulating cylinder is released to the outside air through a pressure release hole formed in the current electrode. At this time, the gas travels to the pressure release hole of the current electrode together with the molten metal in the insulating cylinder, the thermally destroyed resistance element, and the like. The gas on the way to the pressure relief hole becomes a cylindrical flow until immediately before the pressure relief hole in any of the above-mentioned conventional examples, and one of the pressure relief holes has a molten metal attached to the pressure relief hole or has been thermally destroyed. When the gas is blocked by a resistance element or the like, the gas flowing in the axial direction goes to the remaining pressure release holes while rotating in the circumferential direction. In this way, the pressure release holes are closed one after another, pressure release is not sufficiently performed, and the insulating cylinder is ruptured.

If a plurality of axial ribs are formed on the inner side of the insulating cylinder to prevent such a gas from flowing around, for example, a columnar resistance laminated body composed of resistance elements is now completely straight. Since it is not a columnar body, paying attention to any one of the ribs, there are places where the resistive element contacts and places where it does not contact in the longitudinal direction of the rib, and the voltage distribution along the longitudinal direction of the rib becomes non-uniform. The withstand voltage value in the longitudinal direction is reduced, and a discharge may occur at a voltage lower than the limit voltage inherent to the resistance laminate.

An object of the present invention is to provide a structure of a lightning arrester capable of exhibiting a sufficient pressure releasing function without deteriorating the electrical characteristics of the lightning arrester.

[0010]

In order to solve the above-mentioned problems, according to the present invention, a resistance laminated body formed by stacking disk-shaped non-linear resistance elements in a column in an insulating cylinder is insulated by a spring. In a transmission line lightning arrester having a structure fixed to both ends of a cylinder and held between current electrodes connected to an external conductor, a spring is formed as a coiled compression spring and a current electrode in contact with the spring is In the inside of the spring, a plurality of pressure-releasing holes are formed in the insulating cylinder in the axial direction from the inner space side of the insulating cylinder, and when the pressure in the insulating cylinder becomes excessive, the gas in the insulating cylinder that is released to the outside air is coiled. Or through the gap between the compression springs and the pressure release hole in the insulating cylinder axial direction of the current electrode, or at least between the current electrode that does not contact the spring and the resistance laminate, Current electrode side end surface is open and multiple through holes in the peripheral wall The formed metal cylinder is interposed, and the current electrode is provided with a plurality of pressure-releasing holes in the axial direction of the insulating cylinder from the inner space side of the insulating cylinder inside the inner peripheral edge of the metal cylinder. The gas in the insulating cylinder, which is released to the outside air when the pressure becomes excessive in the cylinder, is released to the outside air through the through hole in the peripheral wall of the metal cylinder and the pressure releasing hole in the insulating cylinder axis direction of the current electrode. It is assumed that the apparatus configuration is set as follows.

[0011]

According to the present invention, when the high-pressure gas is released from the inside of the insulating cylinder to the outside air, a plurality of pressure-release holes of the current electrode are discharged to a pressure-release hole which is closed by a molten metal or a thermally destroyed resistance element. The smooth flow of the gas flowing toward it is greatly disturbed by providing an obstacle on the inlet side of the pressure relief hole, and since multiple pressure relief holes are formed, it is difficult for gas to concentrate on a specific pressure relief hole. That is, it is noted that the blocking of the pressure release hole is unlikely to occur. Therefore, if this obstacle is constituted by a coil-shaped compression spring, the flow passing through the gap between the springs will be greatly disturbed, and the molten metal carried by the gas will be cooled by the spring wire and adhere to it, Most of the broken solid material such as the resistance element is prevented from entering the inside of the spring, and moreover, since a plurality of pressure relief holes are formed, it is difficult to close all the pressure relief holes. The effect similar to that of the coiled compression spring is that between the current electrode that does not come into contact with the spring and the resistance laminate, at least the current electrode side end surface is opened and a plurality of through-holes are formed in the peripheral wall. Can also be obtained by interposing. In addition, neither the coiled compression spring nor the metal cylinder has the effect of making the voltage distribution in the longitudinal direction in the insulating cylinder non-uniform, so that the dielectric strength inside the insulating cylinder does not decrease.

[0012]

1 and 2 show one embodiment of the present invention.
A current electrode 13 according to the present invention is provided at an upper end and a lower end of an insulating tube 12 made of FRP, which accommodates a resistance laminated body formed by stacking the disc-shaped non-linear resistance elements 1 in a columnar shape.
13 is fixed using the pin 5 and the two current electrodes 13, 13
Between them, the resistance laminated body, the spring 24, and the cylindrical body 16 described below are held in a state of being pressed against each other in the axial direction. The cylindrical body 16 has an open upper end surface, is formed as a bottomed cylindrical body having an outer diameter smaller than the outer diameter of the resistance element 1, and has a plurality of circular through holes 16a formed in a peripheral wall. As shown in the figure, a plurality of (four in the figure) axial discharge holes 1 are provided in the lower current electrode 13 within the area of the contact surface with the spring 24 inside the spring.
3a is formed and communicates with a radial pressure release hole 13b which communicates with the pressure release hole 12a of the insulating cylinder 12 (FIG. 1).

At the time of lightning strike, an arc is generated in the insulating cylinder 12,
When the gas pressure in the insulating cylinder 12 exceeds a predetermined value, the insulating cylinder 1
The jacket made of a heat-shrinkable organic insulating material, which blocks the outlet of the second pressure release hole 12a, is broken, and the gas blows out to the outside air.
At this time, the gas flow in the upper half of the insulating cylinder 12 is such that the gas flows upward through the cylindrical space between the resistance laminate and the insulating cylinder 12 and hits the peripheral wall of the cylindrical body 16, and the gas flows up to that point. The flow changes from a flow having a ring-shaped cross section to a turbulent flow passing through a through hole in the peripheral wall of the cylindrical body. On the other hand, the molten metal contained in the gas is cooled when passing through the through-hole and adheres around the through-hole, and most of the solid matter carried by the gas is the cylindrical body 1.
6, the amount of molten metal and solids contained in the gas penetrating the peripheral wall of the cylindrical body 16 is small, and the number and size of the pressure release holes 13a are appropriately set. Thereby, the gas can always be reliably discharged to the outside without causing the pressure release hole 13a to be closed.

A spring 24 is formed in a coil shape in almost the lower half of the insulating cylinder 12, and the pressure release hole 13 of the current electrode 13 is formed.
Since a is formed in an area inside the spring on the contact surface with the spring, the spring 24 has the same action as the above-described cylindrical body 16 without closing the pressure release hole 13a. The gas is reliably released to the outside.

[0015]

As described above, according to the present invention, in the insulating cylinder, a resistance laminated body formed by stacking disk-shaped non-linear resistance elements in a columnar shape is provided at both ends of the insulating cylinder via a spring. The transmission line lightning arrester having a structure fixed and held between the current electrodes connected to the outer conductor is provided with a spring formed as a coiled compression spring, and the current electrode in contact with the spring is provided inside the spring. In addition, a plurality of pressure release holes in the axial direction of the insulating cylinder are drilled from the inner space side of the insulating cylinder, and gas in the insulating cylinder that is released to the outside air when excessive pressure is generated in the insulating cylinder is generated by the coil-shaped compression spring. At least the current electrode side end face is discharged to the outside air through the gap and the pressure release hole in the insulating cylinder axis direction of the current electrode, or between the current electrode that does not contact the spring and the resistance laminate. A metal cylinder that is open and has multiple through holes When the current electrode is provided with a plurality of pressure-releasing holes in the axial direction of the insulating cylinder from the inner space side of the insulating cylinder inside the inner peripheral edge of the metal cylindrical body, and an excessive pressure is generated in the insulating cylinder. The lightning arrester has a structure in which the gas in the insulating cylinder released to the outside air is released to the outside air through the through-hole in the peripheral wall of the metal cylinder and the pressure-releasing hole in the insulating cylinder axis direction of the current electrode. Because the arc generated in the insulating cylinder effectively prevents the pressure relief hole from releasing the over-pressure gas to the outside air, the lightning arrester can maintain the intended pressure relief function. The safety of the place is significantly improved as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the structure of a lightning arrester for a transmission line according to the present invention.

FIG. 2 is an enlarged sectional view taken along line AA in FIG.

FIG. 3 is a longitudinal sectional view showing a first example of a conventional structure of a lightning arrester for a transmission line.

FIG. 4 is a longitudinal sectional view showing a second example of a conventional lightning arrester structure for a transmission line.

FIG. 5 is a partial longitudinal sectional view showing a third example of a conventional structure of a lightning arrester for a transmission line.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resistance element 2 Current electrode 4 Insulation cylinder 8 Current electrode 12 Insulation cylinder 13 Current electrode 13a Pressure release hole 16 Cylindrical body 16a Through hole 22 Insulation cylinder 23 Current electrode 24 Spring (coiled compression spring) 28 Insulation cylinder 30 Current electrode 33 Current electrode

Continuation of front page (56) References JP-A-61-63001 (JP, A) JP-A-60-137401 (JP, U) JP-A-62-168605 (JP, U) JP-A-56-159987 (JP) , U) Jikken 54-12657 (JP, Y2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01T 1/15 H01C 7/12

Claims (2)

(57) [Claims] 1. A resistance laminated body formed by stacking disk-shaped non-linear resistance elements in a columnar shape in an insulating cylinder, a current electrode fixed to both ends of the insulating cylinder via a spring and connected to an external conductor. In a lightning arrester for a transmission line having a structure held in between, a spring is formed as a coil-shaped compression spring and a current electrode in contact with the spring is provided inside the spring from the inner space side of the insulating cylinder to the shaft of the insulating cylinder. A plurality of pressure-releasing holes are formed in the insulating cylinder, and when the pressure in the insulating cylinder becomes excessive, the gas in the insulating cylinder is released to the outside air. A lightning arrester for a transmission line, wherein the lightning arrester is discharged to the outside air through a pressure hole. 2. A resistance laminated body formed by stacking disk-shaped non-linear resistance elements in a column shape in an insulating cylinder, and a current electrode fixed to both ends of the insulating cylinder via a spring and connected to an external conductor. In a transmission line lightning arrester having a structure held in between, at least a current electrode side end face is opened and a plurality of through holes are formed in a peripheral wall between a current electrode that does not contact with a spring and a resistance laminate. While the cylindrical body is interposed, the current electrode is formed with a plurality of pressure-releasing holes in the axial direction of the insulating cylinder from the inner space side of the insulating cylinder inside the inner peripheral edge of the metal cylindrical body, and excessively large in the insulating cylinder. The gas in the insulating cylinder which is released to the outside air when the pressure becomes a pressure is released to the outside air through the through-hole in the metal cylindrical body peripheral wall and the pressure releasing hole in the insulating cylinder axial direction of the current electrode. A lightning arrester for a transmission line, characterized in that: