JPH0224364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a lightning arrester, and in particular to a support structure for a non-linear resistance element.

[Background of the Invention] A general lightning arrester is composed of a series connection of a gap having discharge characteristics and a characteristic element. As a characteristic element, we utilize the non-ohmic nature of the contact resistance of SiC particles.

In response, a lightning arrester has been developed that uses a zinc oxide sintered body that has the characteristics of a conventional series-connected body. This zinc oxide sintered body contains ZnO and a small amount of
It is obtained by firing a mixed powder consisting of Bi ₂ O ₃ , CoO, MnO, Sb ₂ O ₃ , Cr ₂ O ₃ , etc. in air.

A lightning arrester using this type of nonlinear resistance is shown in FIG.

A plurality of nonlinear resistance elements 1 are stacked in an insulator tube 3, and connecting plates 4 provided at both ends of the element group are connected by an insulating support rod 2 to support and fix the element group. As can be seen from FIG. 2, three insulating support rods 2 are arranged on the outside of the element 1. The contact pressure between the elements 1 is provided by a spring 6 between the upper terminal plate 5 and the connecting plate 4.

The element 1 is usually manufactured as a disk as shown in FIG. 3 due to conditions such as molding, firing, and surface coating. For this reason, the conventional lightning arrester has a structure in which an insulating support rod 2 is disposed outside the element 1. In this structure, the outer diameter L of the connecting plate 4 is L≧a+2b+2c, where the outer diameter of the element 1 is a, the outer diameter of the insulating support rod 2 is b, and the insulation distance between the element 1 and the insulating support rod 2 is c. ......(1) Therefore, the dimension l ₁ is important in the anti-fouling design of lightning arresters.
(distance between insulator pipe 3 and connection plate 4) cannot be made large,
It is susceptible to fluctuations in the surface potential distribution of the porcelain tube when it is contaminated.
The drawback was that the activation voltage of the lightning arrester was lowered.

Also, a lightning arrester using a metal container instead of the insulator tube 3 is also known. In this type of lightning arrester, the first
In the case of the configuration shown in the figure, a metal container with a large diameter is required due to the connection plate 4.

In addition, in any type of lightning arrester, the element 1
Since a plurality of insulating support rods 2 are used on the outside, the structure is complicated.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a lightning arrester which has a good cooling effect, has a simplified element support structure, and has a reduced diameter of the sealed container.

[Summary of the invention]

In the present invention, the element is constructed as an annular disk body having a through hole in the center, and the laminated element is supported by an insulating support rod inserted into the through hole, and both ends are sealed with terminal plates. It is designed to be placed inside an insulated pipe. Each element has a metallicon layer on both end faces in the stacking direction, and this metallicon layer is provided to have an inner diameter larger than the through hole and a smaller outer diameter than the outer diameter of the element, and is provided between each element and the insulating support rod. By creating a continuous gap between the elements and improving the element support structure, the element support structure can be significantly simplified and cooling can be improved, and the connecting plate can also be made with a diameter equal to or smaller than that of the element. The diameter of the sealed container can be reduced.

[Embodiments of the invention]

The present invention will be explained below with reference to embodiments shown in the drawings.

In FIG. 4, which shows an insulator type lightning arrester, a non-linear resistance element 10 such as a zinc oxide sintered element as a characteristic element is housed in an insulator tube 3. As shown in FIG. 6, the element 10 is an annular disk having a through hole 10b in the center, and metallicon layers 10a are provided on both end faces in the stacking direction. This metallicon layer 10a has an outer diameter smaller than the outer diameter of the element 10 and an inner diameter larger than the inner diameter of the element 10, and the difference in diameter between the two is about 1 to 2 mm. Achieve the effect of

The element 10 having such a configuration is shown in FIGS. 4 and 5.
As shown in the figure, the insulating support rod 11 is supported and fixed to the lower terminal plate 14 of the insulator tube 3, and its through hole 10b is inserted into the insulating support rod 11 to be stacked. A connecting plate 12 is arranged at the upper end of the stacked elements 10, and a pressure spring 13 interposed between the connecting plate 12 and the upper terminal plate 15 of the insulator tube 3 allows
Contact pressure is applied between each element. The upper end of the element 10 is supported by fixing an insulating support 16, such as a pressboard, which is in contact with the inner surface of the porcelain tube 3 to the connecting plate 12.

The connection plate 12 may be independent from the insulating support rod 11, or its upward and radial movement may be restricted by an end fitting attached to the upper end of the insulating support rod 11. The insulating support 16 may be annular, or may be a plurality of plate-shaped supports provided in the circumferential direction.

By providing the insulating support rod 11 in the through hole of the element 10 in this manner, the outer diameter of the connecting plate 12 can be made equal to or smaller than the outer diameter of the element 10. Therefore, the stray capacitance between the element 10 and the inner surface of the insulator tube 3 can be reduced, and the anti-fouling performance of the lightning arrester can be improved. In addition, element 10
By forming the element 10 into an annular shape, a large current can be passed due to the skin effect, and at the same current, the outer diameter of the element 10 can be made the same as the conventional one.

Furthermore, since the annular element 10 used in the present invention has the inner diameter of the metallicon layer 10a on both end faces in the lamination direction larger than the inner diameter of the element 10, creeping flash of the element 10 can be effectively prevented. .

In order to facilitate insertion of the element 10 into the insulating support rod 11, the diameters of the through hole 10b and the insulating support rod 11 may be determined appropriately. For example, they are manufactured with a diameter difference of about 1 mm. If the insulating support rod 11 is made of FRP, for example, its creeping withstand voltage is higher than that of the element 10, so there is no problem even if the insulating support rod 11 partially contacts the elements. However, when corona generation is a problem between the two, the through hole 10b of the element 10
It is best to form a uniform gap over the entire length by coating the wall with an insulating material or by inserting an insulating tube between the two.

FIG. 7, which shows an insulator type lightning arrester according to a different embodiment of the present invention, shows the free end (upper end) of the insulating support rod 11 in FIG. 4, and the other parts have the same structure.

The upper terminal plate 15 has a concave receiving portion 15 on the inner surface at the center thereof.
a is fixed. The insulating support rod 11 is directly or indirectly supported and fixed to the lower end plate below,
It is inserted and guided into the through hole of each element 10. Further, the upper end of the insulating support rod 11 is led out through the element 10 and the connection plate 12, and an end fitting 2 is attached to the end.
5 are screwed together. The end fitting 25 is the receiving part 15a.
The upper end of the insulating support rod 11 is supported by this. Although the insulating support rod 11 may be directly fitted into the receiving portion 15a, it is preferable to provide the end fitting 25 in close contact with it and fitting it into the receiving portion 15a.

As a result of supporting the insulating support rod 11 at both ends in this way, the insulator tube 3 can be placed laterally, and seismic strength for transportation can also be obtained.

Contact pressure is applied between the elements 10 by a pressure spring 13 disposed between the connection plate 12 and the upper terminal plate 15. As mentioned above, the element 10 and the insulating support rod 11
It is desirable to form a uniform gap between them to prevent corona generation. This can be achieved by supporting both ends of the insulating support rod 11 and regulating the position of the elements 10 by the pressure spring 13, but depending on the number of elements 10,
If it is difficult to specify the position of the upper element 10, the fourth
As in the illustrated embodiment, it is preferable to fix the insulating support 16 that contacts the inner surface of the porcelain tube 3 to the connecting plate 12.

The insulating support 16 can also be supported and fixed to something other than the connection plate 12, although this is also the case in FIG. For example, in an embodiment in which a terminal plate is provided between the elements 10 and the metallicon layers are brought into contact with each other,
The insulating support 16 can be fixed to the terminal plate. However, in this case, the terminal plate for fixing the insulating support 16 is preferably located at the upper end as shown.

Moreover, in this way, the element 10 and the insulating support rod 1 are
Forming a uniform gap in the axial direction between the two is particularly effective when a closed container including an insulator tube is filled with viscous SF ₆ gas, as described in the next example. In other words, this gap is used as a gas flow path for the element 1.
0 helps dissipate heat.

This type of lightning arrester suffers from deterioration due to an increase in the temperature of the element. For this reason, it is desirable to provide suitable cooling means.

As described above, in the present invention, the element 10 is supported by the insulating support rod 11 passed through the through hole 10b of the element 10, and the element 10 and the insulating support rod 1 are connected to each other.
The axial gap existing between the two causes a chimney effect and convection. This allows the element 10 to be cooled. However, since the above-mentioned gap is mainly formed due to the ease of assembly work and manufacturing errors, it is not necessarily continuous in the axial direction.
Therefore, in order to obtain this effect, it is necessary to actively form a gap. Furthermore, the following configuration also makes it possible to obtain the cooling effect of the element 10 by taking advantage of the features of the present invention.

In order to prevent external creeping flash between the elements 10, it is preferable to form a predetermined gap between the opposing elements 10, and for this purpose a terminal plate is provided between the elements 10. Therefore, a slit or a hole passing through the element 10 in the radial direction is formed in this terminal plate. According to this, even if there is a discontinuous gap in the axial direction between the element 10 and the insulating support rod 11, a plurality of parallel flow paths are formed via the terminal plate, resulting in a plurality of partial convection currents. . At this time, it is best to make the terminals have a heat dissipation effect or to make them from a material with a large cooling effect.

The insulating support rod 11 in each of the above embodiments may be solid or hollow. In the case of a hollow pipe, that is, an insulated pipe, by providing a large number of holes in the side wall of the pipe, the inside of the hollow part can be used as a gas flow path. Alternatively, a pair of insulating rods having a hollow portion and a solid portion at the ends may be used, and these may be fitted in the middle of the element 10 to form a single insulating support rod. Further, in the present invention, all the elements 10 are supported by one insulating support rod 11, but if the axial length is large, for example, by making the lower part from the end fitting 25 in FIG. 8 into one unit. , can be configured by connecting the necessary units in series or in parallel.

Further, the present invention may also be a lightning arrester equipped with a cooling device as a means for providing a temperature gradient to generate convection, or a lightning arrester equipped with a forced gas circulation device with a flow path between the insulating support rod 11 and the element 10. can.

〔Effect of the invention〕

As explained above, in the present invention, the element is a substantially annular disc body, an insulating support rod is provided through the through hole in the center, and a stack of elements is supported by this, and each element By providing a metallicon layer with an inner diameter larger than the diameter of the hole, it is possible to prevent creeping flash and enable the above-mentioned support structure.
Utilizing the axial gap between each element and the insulating support rod, cooling can be performed effectively and deterioration due to temperature rise can be prevented. Furthermore, by reducing the outer diameter of the connecting plate 12 provided at least at the upper end of the stack of elements, the stray capacitance between the insulator tube and the connecting plate can be reduced, improving electrical performance, and further supporting each element. Excellent effects can be achieved by simplifying the structure.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a conventional lightning arrester, FIG. 2 is a cross-sectional view taken along the line - in FIG. 1, FIG. 3 is a perspective view of the element shown in FIG. A vertical cross-sectional view showing one embodiment, FIG. 5 is the − of FIG.
6 is a perspective view of the element of FIG. 4, and FIG. 7 is a longitudinal sectional view of a different embodiment of the arrester according to the invention. 3... Insulator tube, 10... Element, 10a... Metallicon layer, 10b... Through hole, 11... Insulating support rod, 12... Connection plate, 16... Insulating support, 25
...end fittings.

Claims (1)

[Scope of Claims] 1. A lightning arrester having a plurality of linearly stacked elements in an insulating tube whose both ends are sealed with terminal plates, and in which contact pressure is applied between each element by a pressure spring. , each of the above elements is a substantially annular disc with a through hole in the center, and on both end faces in the stacking direction of each of the above elements,
A metallicon layer having an inner diameter larger than the diameter of the through-hole is provided, and the metallicon layer electrically connects the adjacent elements, and an insulating support with at least one end supported and fixed to the through-hole of each element. A lightning arrester characterized in that a rod is inserted and arranged to form a continuous gap in the axial direction of the insulating support rod between each of the elements and the insulating support rod. 2. In a lightning arrester that has a plurality of linearly stacked elements in an insulator tube whose both ends are sealed with terminal plates, and in which contact pressure is applied between each element by a pressure spring, each of the above-mentioned elements is connected to the center. It is a substantially annular disc body with a through hole in the part, and on both end faces in the stacking direction of each of the above elements,
A metallicon layer having an inner diameter larger than the diameter of the through-hole is provided, and the metallicon layer electrically connects the adjacent elements, and an insulating support rod with at least one end supported and fixed is inserted into the through-hole of each of the elements. a continuous gap in the axial direction of the insulating support rod is formed between each of the elements and the insulating support rod, and the other end of the insulating support rod contacts the inner surface of the insulating tube. A lightning arrester further comprising an insulating support for supporting the element located at the other end. 3. In the device according to claim 2, a connection plate is joined to the element located at the other end of the insulating support rod, and the pressure spring is connected between the connection plate and one of the terminal plates. and the insulating support body is fixed to the connection plate.