JPH0754764B2 - Tank type arrester - Google Patents

Description

TECHNICAL FIELD The present invention relates to a tank type arrester.

[Conventional technology]

The tank-type lightning arrester configured by stacking zinc oxide element groups has a drawback that the potential distribution in the stacking direction of the element groups is biased due to stray capacitance between the element group and the tank. In this regard, conventionally, as described in Japanese Patent Application Laid-Open No. 55-105989, one or more shield rings connected to the high potential side are used to correct the bias of the above-mentioned potential distribution. Alternatively, as described in JP-A-60-44986, by using a capacitance element, the capacitance of the capacitance element is monotonically increased from the low potential terminal side toward the high potential terminal side. The bias of the potential distribution is corrected.

[Problems to be solved by the invention]

The above-mentioned conventional technique has an effect of correcting the bias of the potential distribution in the longitudinal direction of the element group, but in JP-A-60-44986, the effect is obtained unless a capacitance element is provided for all zinc oxide element groups. There is no. In the example of JP-A-55-105989, no consideration is given to the potential of the zinc oxide element group in the vicinity of the shield ring closest to the low voltage side, that is, the lowermost shield ring, and there is a problem that this potential is likely to change suddenly. It was Recently, there has been considered a device in which the cross-sectional area of the element itself is changed to prevent a sudden change in potential. However, with this structure, many element bodies having different cross-sectional areas of the element itself have to be manufactured, and the element cannot be easily manufactured.

The present invention has been made in view of the above points, and it is of course possible to prevent sudden changes in the potential of the zinc oxide element group near the bottom shield ring from suddenly changing, and of course, a tank type arrester that facilitates the production of the element. It is intended to provide.

[Means for solving problems]

The above-mentioned object is to divide the zinc oxide element group into at least three parts including the facing portion facing the shield ring on the ground terminal side, and to the outer periphery of the zinc oxide element group facing the shield ring or in the insulating support member. This is achieved by arranging a capacitor in parallel with the zinc oxide element group.

That is, as shown in FIG. 7 showing a conventional example of a tank type arrester, the internal elements of the arrester, that is, the zinc oxide element group 1 are housed in the grounding tank 2 and the insulating spacer 3
Connected to the high voltage bus bar 4 via. Shield rings 5a and 5b for improving potential distribution are provided at the high-voltage side terminal. In the figure, 6 is a metal fitting. By making the permittivity macroscopically seen in the zinc oxide element group 1b in the vicinity of the lowermost shield ring 5b in the tank type lightning arrester thus configured, larger than the zinc oxide element groups 1a, 1c in the other portions. , The purpose is achieved. Zinc oxide element group 1b
Since the portion is composed of the zinc oxide element and the insulating support member, in order to increase the macroscopic permittivity of this portion, the insulating support member of this portion is made of a material having a large permittivity. A member having a large dielectric constant is juxtaposed to the zinc oxide element group 1b in this portion, or the zinc oxide element group 1b in this portion is arranged.
This can be achieved by connecting a capacitor in parallel with.

[Action]

The dielectric constant of the zinc oxide element group 1b of the tank type arrester shown in FIG.
An example of the electric field analysis of the zinc oxide element group 1 when it is made larger than c is shown when there is no increase.
The equipotential surface 7 concentrated in 1b is dispersed in the zinc oxide element groups 1a and 1c in other portions. That is, the potential sharing ratio is plotted on the vertical axis and the element length of the zinc oxide element group 1 is plotted on the horizontal axis, as shown in FIG. The ratio is improved. That is, in the figure, the electric field concentration increases as the potential sharing ratio is larger than 1, and the curve I shows that the element group of the zinc oxide element group 1b shown in FIG.
The curve II shows the case where the dielectric constant of the zinc oxide element group 1b is about 10% larger than that of the other zinc oxide element groups 1a and 1c. The curve II in which the dielectric constant of the zinc oxide element group 1b is made larger than that of the other zinc oxide element groups 1a and 1c in this way has a potential sharing ratio of 1 compared to the curve I which is not increased.
Approached and improved significantly. By the way, zinc oxide element group 1
The ideal value is 1 when the potential is evenly shared with respect to the unit length in the longitudinal direction. Since this is an element of the same size, the element can be easily manufactured.

〔Example〕

Hereinafter, the present invention will be described based on the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. Since the same parts as those of the prior art are designated by the same reference numerals, the description thereof will be omitted. As shown in the figure, the zinc oxide element group 1, which is an internal element of the arrester, is fixed to the insulating support member 8. In the present embodiment, the zinc oxide element group 1 thus configured is divided into at least three parts including the facing part facing the shield ring on the ground terminal side (lowermost shield ring, not shown), and the shield is formed. A capacitor was arranged in parallel with the zinc oxide element group 1b on the outer periphery of the zinc oxide element group 1b facing the ring. By doing so, the dielectric constant of the zinc oxide element group 1b facing the lowermost shield ring becomes larger than the dielectric constants of the other zinc oxide element groups 1a and 1c, and the zinc oxide element group 1b near the lowermost shield ring 1b. Of course, it is possible to prevent sudden changes in the potential of
Since the same cross-sectional area is required, the element can be easily manufactured. Therefore, it is possible to prevent the sudden change in the potential of the zinc oxide element group in the vicinity of the bottom shield ring and, of course, the tank type lightning arrester that facilitates the element manufacturing. Can be obtained.

That is, on the outer periphery of the zinc oxide element group 1b facing the bottom shield ring, a capacitor is arranged in parallel with the zinc oxide element group 1b, which is a zinc oxide element group 1b and a zinc oxide element group 1a and Support electrodes 9a and 9b are provided between the capacitor cylinder 1 and 1c, and the capacitor cylinder 10 is provided between the support electrodes 9a and 9b and provided on the outer circumference of the zinc oxide element group 1b. By doing so, the capacitor cylinder 10 is provided on the outer circumference of the zinc oxide element group 1b facing the lowermost shield ring, and the dielectric constant of the zinc oxide element group 1b is that of the zinc oxide element groups 1a and 1c. It will be larger than that. Therefore, the electric field concentrated in the zinc oxide element group 1b is relaxed, and it is possible to prevent a sudden change in the potential of the zinc oxide element group 1b.
The potential sharing ratio of the entire zinc oxide element group 1 can be made uniform. Since the potential distribution ratio of the entire zinc oxide element group 1 is thus uniform, the tank type arrester can be made highly reliable and compact. Furthermore, since the same cross-sectional area is sufficient, the device can be easily manufactured.

FIG. 2 shows another embodiment of the present invention. In this embodiment, the capacitor is arranged in parallel with the zinc oxide element group 1b in the insulating support member 8 of the zinc oxide element group 1b facing the lowermost shield ring. The inner insulating support member 8 is a hollow insulating pipe 11, and a connecting metal fitting 12a is provided between the insulating pipe 11 and the zinc oxide element groups 1a, 1c and the insulating support member 8 which are not opposed to each other. , 12b are provided, and the connecting fittings 12a, 12b
And the capacitor 13 provided in the insulating pipe 11. Then, the capacitor 13 was made of barium titanate. That is, since the insulating support member 8 for fixing the zinc oxide element groups 1a, 1b, 1c is usually rod-shaped,
A hollow insulating pipe 11 is used as an insulating support member penetrating the portion 1b, and connecting fittings 12a and 12b are provided at both ends thereof. The insulating support member 8 is connected to the insulating support member 8. A capacitor 13 made of, for example, is enclosed and connected in parallel with the zinc oxide element group 1b. Also in this case, since the dielectric constant of the zinc oxide element group 1b facing the lowermost shield ring is larger than the dielectric constants of the other zinc oxide element groups 1a and 1c, the elements of the same size may be used. The same operational effect as can be obtained.

FIG. 3 shows still another embodiment of the present invention. As shown in the figure, the present embodiment is a case where the zinc oxide element group 1 is composed of a plurality of cylindrical zinc oxide element stacks 14a, 14b, 14c. And this zinc oxide element 15
Zinc oxide elements 15a, 1 of a plurality of zinc oxide element laminates 14a, 14b, 14c in which a, 15b, 15c are laminated around the insulating support member 8
5b and 15c are electrically connected in series by an insulating plate 16 that is spirally wound, and zinc oxide elements 15a, 15b and 15 are connected in series.
Insulating plates 17, 17a, 17b, 17c are electrically connected in parallel for every predetermined number of c. In the zinc oxide element group 1 configured as described above, in this embodiment, the zinc oxide element group 1 is at least 3 including the facing portion facing the lowermost shield ring.
It is divided into two parts (only two parts are shown), and the insulating plates 17a, 17b, 17c of the zinc oxide element group 1b in the facing part have a larger dielectric constant than the insulating plates 17 of the zinc oxide element group 1a in the other parts. I tried to be. By doing so, the dielectric constant of the insulating plates 17a, 17b, 17c of the zinc oxide element group 1b in the facing portion becomes larger than the dielectric constant of the insulating plate 17 of the zinc oxide element group 1a in the non-facing portion, The element group 1b has a higher dielectric constant than the zinc oxide element group 1a, and the elements may have the same cross-sectional area. Therefore, the same effect can be obtained in the above case.

That is, the same zinc oxide element laminated body, for example, the zinc oxide element 15a laminated on the zinc oxide element laminated body 14a is the insulating plate 16
Is insulated by the insulating plate 17 every time the spiral is rotated once.
Since the insulating plates 17a, 17b, 17c of the zinc oxide element stacks 14a, 14b, 14c of the zinc oxide element group 1b facing the bottom shield ring are made of a high dielectric constant sintered material such as barium titanate, Zinc oxide element 1 of each zinc oxide element laminate 14a, 14b, 14c
5a, 15b, and 15c have a shape in which one capacitor element is connected in parallel each time the insulating plate 16 makes one spiral turn (see the fourth section), and the zinc oxide element group 1b is macroscopically viewed. The dielectric constant can be made larger than that of the other zinc oxide element group 1a. In this case, the insulating plates 17b and 17c may be formed of an ordinary insulating material, that is, an insulating material having a small dielectric constant, if necessary.

In this embodiment, the insulating plates 17a, 17b, 17c of the zinc oxide element group 1b in the facing portion are formed of a barium titanate sintered body, but the present invention is not limited to this. , Polyethylene, polystyrene, polyethylene terephthalate, a thin film aggregate of polycarbonate, or the like.

5 and 6 show another embodiment of the present invention. In this embodiment, the insulating plate 18 of the zinc oxide element group of the facing portion is pressed into the hollow hole 19 provided in the insulating plate 18, and the metal fitting 20,
It is formed by a capacitor 22 provided via a holding spring 21. By doing so, the dielectric constant of the zinc oxide element group in the facing portion facing the lowermost shield ring becomes larger than the dielectric constant of the zinc oxide element group in the other non-facing portion, which is similar to the above case. It is possible to obtain the action and effect.

〔The invention's effect〕

As described above, the present invention divides the zinc oxide element group into at least three portions including the facing portion facing the shield ring on the ground terminal side (the lowest stage), and the zinc oxide element group facing the shield ring. Since a capacitor is arranged in parallel with the zinc oxide element group on the outer periphery of the device or in the insulating support member, the dielectric constant of the zinc oxide element group facing the bottom shield ring is the dielectric constant of other zinc oxide element groups. It is possible to prevent the sudden change in the potential change of the zinc oxide element group in the vicinity of the lowermost shield ring, and the same cross-sectional area makes it easier to manufacture the element. It is possible to obtain a tank type lightning arrester which can prevent the sudden change in the potential of the zinc oxide element group and facilitates the manufacture of the element.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a lightning arrester main part of an embodiment of a tank type lightning arrester of the present invention, and FIG. 2 is a vertical side view of a lightning arrester main part of another embodiment of a tank type lightning arrester of the present invention. Is a perspective view of the essential parts of the arrester of still another embodiment of the tank arrester of the present invention, FIG. 4 is an electrical equivalent circuit diagram of FIG. 3, and FIG. 5 is still another embodiment of the tank arrester of the present invention. A plan view of an insulating plate as an example, FIG. 6 is a cross-sectional view taken along the line AA of FIG. 5, FIG. 7 is a vertical side view of a conventional tank type lightning arrester, and FIG. 8 is a lightning arrester of a conventional tank type lightning arrester. FIG. 9 is an electric field analysis diagram of internal elements, and FIG. 9 is a change characteristic diagram of the potential sharing ratio depending on the element length when the dielectric constant of the zinc oxide element group of the portion facing the bottom shield ring is increased and when it is not increased. 1 ... Lightning arrester internal element (zinc oxide element group), 1a ... Zinc oxide element group in non-opposing portion, 1b ... Zinc oxide element group in opposing portion, 1c ... Zinc oxide element group in non-opposing portion, 2 ... … Grounding tank, 4 …… High voltage busbar, 5a …… Shield ring, 5b
...... Bottom shield ring (shield ring on the ground terminal side), 8 ... Insulating support member, 9a, 9b ... Support electrode, 10 ...
… Condenser tube, 11 …… Insulation pipe, 12a, 12b …… Coupling metal, 13 …… Capacitor, 14a, 14b, 14c …… Zinc oxide element laminate, 15a, 15b, 15c …… Zinc oxide element, 16 …… Connection plate, 17 ... Insulating plate of zinc oxide element group in non-opposing part, 17a,
17b, 17c, 18 ... Insulating plate of zinc oxide element group in the facing portion, 19
...... Hollow hole, 20 ...... Presser fitting, 21 ...... Presser spring, 22 ......
Capacitors.

Claims (6)

[Claims] 1. A zinc oxide element group stacked in a ground tank and supported around an insulating support member has one axial end connected to a ground terminal and the other axial end connected to a high voltage terminal. At the same time, in the tank type arrester in which the zinc oxide element group is provided with a concentric shield ring for improving potential distribution surrounding the zinc oxide element group, the zinc oxide element group faces the shield ring on the ground terminal side. The capacitor is arranged in parallel with the zinc oxide element group in at least three parts including the facing portion and on the outer periphery of the zinc oxide element group facing the shield ring or in the insulating support member. Characteristic tank type arrester. 2. The tank type arrester according to claim 1, wherein the capacitor is formed of barium titanate. 3. A grounding tank, one end of which in the axial direction is connected to a grounding terminal, the other end of which in the axial direction is connected to a high-voltage terminal, and a concentric circular potential distribution around the same for improving the potential distribution. A zinc oxide element group provided with a shield ring, the zinc oxide element group being juxtaposed in the ground tank, and a plurality of zinc oxide elements stacked around an insulating support member. The zinc oxide elements of the element stack are electrically connected in series by a spirally wound connection plate, and insulating plates are electrically connected in parallel for each predetermined number of zinc oxide elements connected in series. In the connected tank type arrester, the zinc oxide element group is divided into at least three parts including the facing part facing the shield ring on the side of the ground terminal, and the zinc oxide element group facing the shield ring. Tank type arrester, characterized in that the formation of the insulating plate as an insulating plate of the zinc oxide element groups in the other part becomes a large dielectric constant. 4. The insulating plate of the zinc oxide element group of the facing portion is formed of a sintered body mainly containing barium titanate or a sintered body mainly containing strontium titanate. Tank type lightning arrester according to the third paragraph. 5. The insulating plate of the zinc oxide element group of the facing portion is formed of a thin film integrated body of any one of polyethylene, polystyrene, polyethylene terephthalate, and polycarbonate. Tank type arrester. 6. The insulating plate of the zinc oxide element group of the facing portion is formed of a capacitor provided in a hollow hole formed in the insulating plate via a holding metal and a holding spring. Tank type lightning arrester described in item 3.