JP2001237109A - Surge arrester - Google Patents

Abstract

(57) [Problem] To provide a lightning arrester in which an air gap between arcing horns causes dielectric breakdown earlier than before. A plurality of non-linear resistance elements are housed in a state in which a plurality of non-linear resistance elements are stacked inside an insulating cylinder having an outer periphery covered with an organic insulating material, and arcing horns are provided at both ends of the insulating cylinder. In the lightning arrester in which the electrodes 5 are provided and the arcing horns 6 form an air gap outside the insulating cylinder 11, a linear groove 12 is formed on the surface of the insulating cylinder 11 so as to be long in the stacking direction of the nonlinear resistance element 1. You.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester having electrodes provided with arcing horns at both ends thereof, and more particularly to a lightning arrester in which an internal nonlinear resistance element hardly scatters to the outside even when an internal failure occurs.

[0002]

2. Description of the Related Art A lightning arrester is for protecting power equipment from lightning and switching surges. FIG. 5 is a cross-sectional view showing the structure of a conventional lightning arrester. The outer periphery of the insulating tube 2 is covered with an organic insulating material 3, and a plurality of non-linear resistance elements 1 mainly composed of zinc oxide are stored inside the insulating tube 2 in a stacked state. A circumferential groove 9 is formed in the inner diameter wall of the insulating cylinder 2. Metal fittings 4 are screwed to both ends of the insulating cylinder, and the metal fittings 4 hold the nonlinear resistance element 1 via a compressible spring 10. Further, an electrode 5 is attached to the metal fitting 4, and arcing horns 6 are protrudingly provided in the outside air portion of the electrode 5.

In FIG. 5, an insulating cylinder 2 is made of an organic insulating material 3.
It is molded and protected from the environment in the outside air. On the other hand, the insulating cylinder 2 is for protecting the built-in nonlinear resistance element 1 from absorbing moisture. A thin portion 2 </ b> A is formed in the insulating cylinder 2 by the circumferential groove 9. The thin portion 2A is for preventing the internal non-linear resistance element 1 from scattering to the outside air part when an internal failure occurs. That is, if the non-linear resistance element 1 breaks down during operation due to insulation deterioration or the like, an internal arc is generated in the insulating cylinder 2. As a result, the internal pressure of the insulating cylinder 2 increases, the thin portion 2A is broken, and the high-temperature and high-pressure gas 8 of the internal arc blows out of the insulating cylinder 2 as shown in FIG. Since the high-temperature and high-pressure gas 8 is interposed in the air gap 6A between the arcing horns 6, the air gap 6A is broken down, and the arc inside the insulating cylinder 2 is indicated by a dotted line.
To the external arc 7 of FIG. At the same time, the internal pressure of the insulating cylinder 2 decreases. Without the arcing horn 6, the internal pressure of the insulating cylinder 2 continues to rise. As a result, when the internal pressure of the insulating cylinder 2 becomes considerably high, the insulating cylinder 2 is broken, and the internal nonlinear resistance element 1 is greatly scattered to the outside air part, so that safety cannot be maintained. Thin section 2A in advance
Is provided, the position at which the high-temperature and high-pressure gas 8 is blown out can be limited, and the internal pressure of the insulating cylinder 2 can be prevented from extremely increasing.

[0004]

However, the conventional lightning arrester as described above has a problem that the arcing horn has a long destruction time when an internal failure occurs. In other words, in FIG. 5, when an internal failure occurs, the air gap 6A between the arcing horns 6 is broken down as quickly as possible, and the internal pressure rise of the insulating cylinder 2 is moderated so that the nonlinear resistance element 1 scatters around. Can be reduced. Thereby, surrounding safety can be improved. In the apparatus of FIG. 5, since the area in which the high-temperature and high-pressure gas 8 blows out is small with respect to the entire length of the external arc 7, the time until the air gap 6A between the arcing horns 6 breaks down the entire path is delayed. . The rise in the internal pressure of the insulating cylinder 2 was correspondingly high, and the degree of scattering around the nonlinear resistance element 1 was large. SUMMARY OF THE INVENTION It is an object of the present invention to provide a lightning arrester in which an air gap between arcing horns causes dielectric breakdown earlier than before.

[0005]

According to the present invention, in order to achieve the above object, a plurality of non-linear resistance elements are stacked inside an insulating cylinder whose outer periphery is covered with an organic insulating material. An electrode provided with an arcing horn is provided at both ends of the insulating cylinder, and the arcing horns form an air gap outside the insulating cylinder. It is preferable to form a groove that is long in the element stacking direction. As a result, the thin portion formed by the groove of the insulating cylinder is elongated in the axial direction of the insulating cylinder. Intervenes over the entire length of the gap. For this reason, the air gap between the arcing horns is easily broken down earlier than in the past, and the rise in the internal pressure of the insulating cylinder can be suppressed accordingly. Further, in such a configuration, the groove may be linear. In such a configuration, the groove may be spiral.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. FIG. 1 is a cross-sectional view showing a configuration of a lightning arrester according to an embodiment of the present invention. FIG. 2 is a view showing only an insulating tube 11 shown in FIG. 1, and FIG.
FIG. 3B is a sectional view taken along line XX of FIG. Insulation tube 1
A linear groove 12 is provided in the inner peripheral wall of the first inner peripheral wall so as to be long in the axial direction. The rest of FIG. 1 is the same as the conventional configuration of FIG. 5, and the same parts as those of the conventional art are denoted by the same reference numerals and detailed description thereof will be omitted. In FIG. 1, a vertically long thin portion 11 </ b> A is formed in an insulating cylinder 11. When an internal failure occurs in the lightning arrester, the high-temperature and high-pressure gas 13 blown out from the inside of the insulating tube 11 to the outside is interposed over the entire length of the air gap 6A of the arcing horn 6 as shown in FIG. As a result, the air gap 6A between the arcing horns 6 is easily broken down, and the internal arc of the insulating cylinder 11 easily shifts to the external arc 7 earlier than before. The rise in the internal pressure of the insulating cylinder 2 can be suppressed by that much, and the extent to which the nonlinear resistance element 1 scatters around can be reduced. Thereby, safety is improved as compared with the related art. In addition,
The arcing horn 6 and the thin portion 11A need not be provided on the same plane as in FIG. In FIG. 1, the arcing horn 6 is formed on the left side of the insulating tube 11, and even if the arcing horn 6 and the thin-walled portion 11 </ b> A are at positions different from each other by 180 degrees, the root of the external arc 7 easily goes around the arcing horn 6. The conditions under which the air gap 6A tends to cause dielectric breakdown are almost the same.

FIG. 3 is a sectional view showing the structure of a lightning arrester according to a different embodiment of the present invention. FIG. 4 is a view showing only the insulating tube 15 of FIG. 3, and FIG. FIG. 4B is a sectional view taken along the line YY of FIG. In FIG. 3, a helical groove 16 is formed in the insulating tube 15, and a helical thin portion 15A that is long in the axial direction is formed. 3 is the same as the conventional configuration in FIG. When an internal failure occurs in the lightning arrester, the high-temperature and high-pressure gas 14 blown out from the inside of the insulating cylinder 15 to the outside is interposed over the entire length of the air gap 6A of the arcing horn 6 as shown in FIG. For this reason, the air gap 6A between the arcing horns 6 is easily broken down, and the internal arc of the insulating tube 15 easily shifts to the external arc 7 earlier than before. The rise in the internal pressure of the insulating tube 15 can be suppressed by that much, and the extent to which the nonlinear resistance element 1 scatters around can be reduced. Thereby, safety is improved as compared with the related art. However, in FIG.
Blows out not only to the right half surface of the insulating tube 15 but also to the entire outer peripheral portion of the insulating tube 15.

The present invention is not limited to the above embodiment. A groove formed in the insulating cylinder may be provided on the outer peripheral wall of the insulating cylinder to form a thin portion. Further, the groove may be bent or zigzag. In short, if the groove is long connected in the stacking direction of the nonlinear resistance element, the high-temperature and high-pressure gas blown out from the inside of the insulating cylinder will intervene over the entire length of the air gap of the arcing horn. It is easy to destroy.

[0009]

As described above, according to the present invention, by forming a groove which is long in the stacking direction of the non-linear resistance element on the surface of the insulating cylinder, the air gap between the arcing horns is made faster than before. The insulation is easily broken, and the extent to which the non-linear resistance element is scattered to the surroundings is extremely reduced, so that the safety can be further improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of a lightning arrester according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing only the insulating cylinder of FIG. 1 taken out, wherein FIG. 2A is a horizontal sectional view, and FIG.
X sectional view

FIG. 3 is a sectional view showing the configuration of a lightning arrester according to another embodiment of the present invention;

4A and 4B are diagrams showing only the insulating cylinder of FIG. 3 taken out, in which FIG. 4A is a horizontal sectional view, and FIG.
Y sectional view

FIG. 5 is a sectional view showing a configuration of a conventional lightning arrester.

[Explanation of symbols]

1: nonlinear resistance element, 2, 11, 15: insulating cylinder, 2A,
11A, 15A: thin portion, 3: organic insulating material, 4: metal fittings, 5: electrode, 6: arcing horn, 6A: air gap, 7: external arc, 8, 13, 14: high temperature and high pressure gas,
9: circumferential groove, 12: straight groove, 16: spiral groove

Claims (3)

[Claims] A plurality of non-linear resistance elements are housed in a stacked state inside an insulating cylinder whose outer periphery is covered with an organic insulating material, and electrodes having arcing horns at both ends of the insulating cylinder are provided. In the lightning arrester provided, wherein the arcing horns form an air gap outside the insulating cylinder, a groove is formed on the surface of the insulating cylinder so as to be long connected in the stacking direction of the non-linear resistance element. Lightning arrester. 2. The lightning arrester according to claim 1, wherein said groove is straight. 3. The lightning arrester according to claim 1, wherein said groove is helical.