WO2021140593A1

WO2021140593A1 - Polymer-type lightning arrester

Info

Publication number: WO2021140593A1
Application number: PCT/JP2020/000336
Authority: WO
Inventors: 成彦後藤; 富和安食; 良昌阿嘉; 靖宣春日; 深野　孝人
Original assignee: 株式会社東芝; 東芝エネルギーシステムズ株式会社
Priority date: 2020-01-08
Filing date: 2020-01-08
Publication date: 2021-07-15

Abstract

The present invention provides a polymer-type lightning arrester that ensures a high mechanical strength and economical efficiency, that can reduce stress generated in an insulating rod when a bending load is applied, by dispersing bending moment generated at the base of the lightning arrester, and that is applicable to a high-rated lightning arrester. In a mold-type lightning arrester 20, an element pillar 19 of a nonlinear resistor 1 and electrodes 5a, 5b disposed at both ends of the element pillar 19 are fastened together by a plurality of insulating rods 2 so as to form an inner element 18, and the inner element 18 is directly molded by using a silicone rubber 13. In the polymer-type lightning arrester 20, right screw holes 8 which are first screw holes are provided to the electrodes 5a, 5b. Counter boring holes 9 are formed so as to be continuous from the right screw holes 8. Spacers 10 are fitted in the counter boring holes 9. Left screw holes 11 which are second screw holes are provided to the spacers 10. Two screw bolts 12 which apply axial force to the nonlinear resistor 1 are mounted to the screw holes 8, 11.

Description

Polymer type arrester

The embodiment according to the present invention relates to a polymer type lightning arrester.

A lightning arrester that protects power equipment from overvoltage such as lightning strikes is an indispensable device for realizing high-quality power supply. In recent years, polymer type arresters have become widespread as lightning arresters that are excellent in compactness and weight reduction. In the polymer type arrester, a plurality of insulating rods for increasing the rigidity are arranged around a non-linear resistor in which a plurality of layers are laminated. A non-linear resistor and an insulating rod are used as internal elements of the arrester. In polymer arresters, the outer cover is provided by directly molding this internal element with silicone rubber.

Generally, a lightning arrester needs a predetermined mechanical strength in consideration of the load during installation work and vibration due to wind. In a polymer type arrester, since the material of the outer cover is silicone rubber, it is difficult to obtain mechanical strength by the outer cover. Therefore, the polymer type arrester secures the mechanical strength by the insulating rod arranged around the non-linear resistor and the element column which is a laminate of the non-linear resistors.

JP 2013-229362 JP 2014-22632

By the way, the bending moment due to the bending load on the arrester is generated at the base of the arrester. Since the mechanical strength of the polymer type arrester depends on the strength of the insulating rod in particular, the damaged portion due to the bending moment is often the root portion of the insulating rod. Therefore, in the conventional polymer type arrester, by increasing the size and the number of insulating rods, it is possible to avoid damage to the base of the insulating rods and increase the mechanical strength of the arrester. However, increasing the size and number of insulating rods leads to an increase in size and complexity of the polymer type arrester, which leads to an increase in cost.

When comparing a polymer type arrester and an insulator type arrester that uses a porcelain insulator as the material of the outer cover, the former is more compact and lighter, so in terms of economy, the polymer type arrester is more economical than the insulator type arrester. Is more advantageous. For this reason, polymer arresters are required to maintain good economic efficiency. In terms of mechanical strength, the polymer type arrester depends only on the internal elements compared to the insulator type arrester that fully satisfies the seismic performance, so the mechanical strength must be lower than that of the insulator type arrester. .. Therefore, the polymer type arrester is required to have a constant improvement in mechanical strength.

Currently, the development of a polymer type arrester that can also be applied to high-rated arresters is awaited, but with high-rated arresters, the overall height and weight will increase. Therefore, it is necessary to further increase the mechanical strength of the polymer type arrester that can be applied to the high rated lightning arrester. Against the background of the above points, in the polymer type arrester, it is an issue to further improve the mechanical strength while maintaining good economic efficiency.

The embodiment of the present invention has been made to solve the above-mentioned problems, and relaxes the stress generated in the insulating rod when a bending load is applied by dispersing the bending moment generated at the base of the arrester. It is possible to apply it to high-rated lightning arresters, and it is an object of the present invention to provide a polymer type arrester that secures high mechanical strength and economy.

Means for the invention to be solved

In order to achieve the above object, an embodiment of the present invention includes an element column of a non-linear resistor containing one or a plurality of laminated zinc oxide as a main component, and electrodes arranged at both ends of the element column. In a polymer type lightning arrester in which the internal element is directly molded with silicone rubber by fastening with a plurality of insulating rods to form an internal element, the electrode is provided with a screw hole and a bolt, and the screw hole is continuously connected to the screw hole. A counterbore hole is formed, a spacer is fitted in the counterbore hole, a second screw hole is provided in the spacer, and the shaft of the non-linear resistor is provided in the first screw hole and the second screw hole. Install the force-applying bolts.

Longitudinal sectional view of the first embodiment

Embodiment of the invention

Hereinafter, the polymer type lightning arrester according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a vertical cross-sectional view of the polymer type lightning arrester according to the first embodiment.

(Constitution)
As shown in FIG. 1, the polymer type lightning arrester 20 is provided with a plurality of non-linear resistors 1 laminated. The non-linear resistor 1 is a disk-shaped zinc oxide element containing zinc oxide as a main component. A columnar element column 19 is formed by stacking a plurality of disk-shaped non-linear resistors 1. A plurality of insulating rods 2 are arranged around the element column 19 in order to increase the rigidity of the polymer type lightning arrester 20.

A plurality of insulating rods 2 are arranged at equal intervals around the element pillar 19. The insulating rod 2 tightens the non-linear resistor 1 from the surroundings so that the positions of the non-linear resistors 1 do not shift. The insulating rod 2 is made of, for example, a rod-shaped member made of FRP having a diameter of 10 mm or more. The non-linear resistor 1 and the insulating rod 2 are used as the internal element 18 of the polymer type lightning arrester 20. In the polymer type arrester 20, the outer cover is provided by directly molding the internal element 18 with the silicone rubber 13.

An FRP insulating plate 3 is arranged at approximately the center of the element column 19 in the height direction. The insulating rod 2 is fixed to the insulating plate 3 in order to prevent the insulating rod 2 from being displaced. Electrodes 5a and 5b are fixed to the lower end and the upper end of the insulating rod 2. The electrodes 5a and 5b are provided with holes 4a and 4b for fastening having an inclined surface at positions corresponding to the ends of the insulating rod 2.

The hole provided in the lower electrode 5a is referred to as a pilot hole 4a, and the hole provided in the upper electrode 5b is referred to as an upper hole 4b. The prepared hole 4a is a truncated cone-shaped hole whose diameter gradually narrows upward, and the upper hole 4b is a truncated cone-shaped hole whose diameter gradually narrows downward.

Wedge-shaped spacers 6a and 6b are inserted into the pilot hole 4a and the upper hole 4b, respectively. The spacer 6a is inserted into the prepared hole 4a so that the sharp end is located on the upper side, and the spacer 6b is inserted into the upper hole 4b so that the sharp end is located on the lower side. The insulating rod 2 and the electrodes 5a and 5b are fastened by inserting the spacers 6a and 6b into the holes 4a and 4b from the end faces of the electrodes 5a and 5b.

A Teflon sheet 7 having a thickness of 0.1 to 0.2 mm is attached to the surfaces of the spacers 6a and 6b. By attaching the Teflon sheet 7 between the spacers 6a and 6b and the contact surfaces of the electrodes 5a and 5b, the friction coefficients of the two are equalized.

A right-hand screw hole 8 is provided at the center of the electrodes 5a and 5b. In the central portion of the electrodes 5a and 5b, a counterbore hole 9 which is a cylindrical hole is provided on the side closer to the non-linear resistor 1 continuous with the right-hand screw hole 8. The counterbore hole 9 is concentric with the right-hand screw hole 8 and is formed at the center of the electrodes 5a and 5b so as to be one step wider than the diameter of the right-hand screw hole 8. A cylindrical spacer 10 is fitted in the counterbore hole 9. The spacer 10 is made of aluminum.

In the first embodiment, the clearance between the inner peripheral surface of the counterbore hole 9 and the outer peripheral surface of the spacer 10 is set to 2 mm. The depth dimension of the counterbore hole 9 is set to be shallower than the height dimension of the spacer 10. Therefore, when the spacer 10 is fitted into the counterbore hole 9, the end face of the spacer 10 protrudes closer to the non-linear resistor 1 than the end faces of the electrodes 5a and 5b. Further, the diameter of the spacer 10 is set to, for example, 40% or more and 90% or less of the diameter of the non-linear resistor 1.

A left-handed screw hole 11 is provided in the center of the spacer 10 concentrically with the right-handed screw hole 8. Both screw bolts 12 are inserted into the right-hand thread hole 8 and the left-hand thread hole 11. The electrodes 5a and 5b and the spacer 10 are connected by the double-threaded bolt 12. By tightening both screw bolts 12, an axial force is applied to the non-linear resistor 1. That is, the double-threaded bolt 12 provided on the lower electrode 5a applies an axial force to the non-linear resistor 1 from the lower side to the upper side, and the double-threaded bolt 12 provided on the upper electrode 5b is applied to the non-linear resistor 1. Axial force is applied from above to below.

(Action)
In the polymer type arrester 20 as described above, a counterbore hole 9 is provided in the central portion of the electrodes 5a and 5b, and the spacer 10 is fitted in the counterbore hole 9, so that the root portion of the polymer type arrester 20 is subjected to a bending load (FIG. 1). The bending moment generated in the cross section AA) can be dispersed between the insulating rod 2 and the spacer 10. Therefore, it is possible to relieve the stress generated in the insulating rod 2.

As a result of analyzing the bending strength of the lightning arrester in the first embodiment, the bending moment (pu) of the polymer type arrester 20 with respect to the stress generated in the insulating rod 2 is when the conventional structure is "1". , In the first embodiment, it could be "1.2". That is, by applying the first embodiment to the polymer type arrester, the mechanical strength was improved by 20%.

(effect)
In the molded lightning arrester 20 according to the first embodiment, the element column 19 of the non-linear resistor 1 and the electrodes 5a and 5b arranged at both ends of the element column 19 are fastened by a plurality of insulating rods 2. In the polymer type arrester 20 in which the internal element 18 is used as the internal element 18 and the internal element 18 is directly molded with the silicone rubber 13, the electrodes 5a and 5b are provided with the right-hand screw holes 8 which are the first screw holes and are continuous with the right-hand screw holes 8. A counterbore hole 9 is formed, a spacer 10 is fitted in the counterbore hole 9, a left screw hole 11 which is a second screw hole is provided in the spacer 10, and a non-linear resistor 1 is provided in these

screw holes

8 and 11. A double-threaded bolt 12 that gives axial force to the screw bolt 12 is attached.

In the mold type arrester 20 having the above configuration, since the spacer 10 is fitted into the counterbore holes 9 formed in the electrodes 5a and 5b, the bending moment generated at the root of the polymer type arrester 20 when a bending load is applied can be generated. It can be dispersed in the root portion of the insulating rod 2 and the spacer 10. Therefore, it is possible to relax the stress generated in the insulating rod 2 as compared with the case where the bending moment is received only by the insulating rod 2.

Further, in the molded lightning arrester 20 according to the first embodiment, the electrodes 5a and 5b are connected to the spacer 10 by the double-threaded bolts 12 inserted into the right-handed screw hole 8 and the left-handed screw hole 11, and the double-threaded bolt 12 is connected. By tightening, axial force can be applied to the non-linear resistor 1. That is, the tightening structure including the screw holes 8 and 11 and the bolt 12 can increase the axial force with respect to the non-linear resistor 1. Therefore, in the mold type arrester 20 that depends only on the internal element 18 for the mechanical strength, the mechanical strength can be significantly improved. Specifically, the mechanical strength was improved by 20% as compared with the conventional structure. As a result, the mold type arrester 20 according to the first embodiment can be sufficiently applied to a highly rated lightning arrester whose total height and mass increase.

Moreover, in the polymer type arrester 20, no change is made in that the internal element 18 is directly molded with the silicone rubber 13. Therefore, the molded lightning arrester 20 can maintain compactness and weight reduction, and the economy remains good. Therefore, according to the first embodiment, it is possible to provide a polymer type lightning arrester that ensures high mechanical strength and economy.

Further, in the mold type arrester 20 according to the first embodiment, the clearance between the counterbore hole 9 and the spacer 10 is set to 2 mm. Therefore, the silicone rubber 13 can be smoothly poured from this clearance, and the fluidity of the silicone rubber 13 can be easily ensured. Therefore, the work cost does not increase when the silicone rubber 13 is directly molded.

Further, in the molded lightning arrester 20 according to the first embodiment, since the diameter of the spacer 10 is 40% or more of the diameter of the non-linear resistor 1, a sufficient size can be secured as the diameter of the spacer 10. , The mechanical strength can be improved by the spacer 10. At the same time, in the molded lightning arrester 20 according to the first embodiment, the diameter of the spacer 10 is suppressed to 90% or less of the diameter of the non-linear resistor 1, so that the counterbore holes 9 corresponding to the spacer 10 in the electrodes 5a and 5b The diameter of is not too large.

Therefore, in the mold type arrester 20, it is possible to surely form the pilot hole 4a and the upper hole 4b for fastening the insulating rod 2 in the electrodes 5a and 5b. As a result, the plurality of insulating rods 2 fastened to the prepared hole 4a and the upper hole 4 can be efficiently arranged at desired positions of the electrodes 5a and 5b. Therefore, the non-linear resistor 1 can be accurately positioned by the insulating rod 2 and can contribute to the improvement of the mechanical strength of the molded lightning arrester 20.

Moreover, in the molded lightning arrester 20 according to the first embodiment, the right-hand screw holes 8 of the electrodes 5a and 5b and the left-hand screw holes 11 of the spacer 10 are communicated with each other to form the right-hand screw holes 8 and the left-hand screw holes 11. Since the double-threaded bolt 12 is inserted, the axial force applied to the non-linear resistor 1 can be easily adjusted with a very simple structure. Therefore, in the first embodiment, a desired mechanical strength can be obtained without complicating the configuration, and both high mechanical strength and good economic efficiency can be achieved at the same time.

(Other embodiments)
Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

In the first embodiment described above, there is one right-hand screw hole 8 and one left-hand screw hole 11 communicating with each other in each of the electrodes 5a and 5b and the spacer 10, but a plurality of right-hand screw holes 8 and a plurality of left-hand screw holes 11 may be provided. When a plurality of right-hand screw holes, which are the first screw holes, are provided, a plurality of counterbore holes 9 may be provided corresponding to the screw holes. In such an embodiment, not only the number of spacers 10 is increased, but also a plurality of bolts 12 for applying an axial force to the non-linear resistor 1 can be provided, so that the mechanical strength can be further improved.

In the first embodiment described above, the clearance between the counterbore hole 9 and the spacer 10 is set to 2 mm, but the inner peripheral dimension of the counterbore hole 9 and the outer peripheral dimension of the spacer 10 are made the same, and the clearance is not set. The spacer 10 may be fitted into the counterbore hole 9. According to such an embodiment, since the spacer 10 does not move in the counterbore hole 9, the vibration resistance is improved and the mechanical strength is further improved. Although the spacer 10 in the first embodiment is made of aluminum, the spacer 10 is not limited to this, and may be made of FRP, for example.

1 ... Non-linear resistor 2 ... Insulation rod 3 ... Insulation plate 4a, 4b ... Inclined holes 5a, 5b ... Electrodes 6a, 6b ... Spacer 7 ... Teflon sheet 8 ... Right-hand screw hole 9 ... Counterbore hole 10 ... Spacer 11 ... Left-hand screw hole 12 ... Double-threaded bolt 13 ... Silicone rubber 18 ... Internal element 19 ... Element pillar 20 ... Polymer type lightning arrester

Claims

An element column of a non-linear resistor containing zinc oxide as a main component and electrodes arranged at both ends of the element column are fastened by a plurality of insulating rods to form an internal element. In a polymer type arrester in which the internal elements are directly molded with silicone rubber,
A first screw hole is provided in the electrode, and a counterbore hole is continuously formed in the first screw hole.
A spacer is fitted into the counterbore hole.
The spacer is provided with a second screw hole.
A polymer type lightning arrester in which a bolt that gives an axial force to the non-linear resistor is attached to the first screw hole and the second screw hole.
The polymer type lightning arrester according to claim 1, wherein the clearance between the inner peripheral surface of the counterbore hole and the outer peripheral surface of the spacer is 0 or more and 2 mm or less.
The polymer type lightning arrester according to claim 1 or 2, wherein the diameter of the spacer is 40 or more and 90% or less of the diameter of the non-linear resistor.
The polymer type lightning arrester according to any one of claims 1 to 3, wherein the first screw hole and the second screw hole are communicated with each other.
Of the first screw hole and the second screw hole, one is a right-hand screw hole and the other is a left-hand screw hole.
The polymer type lightning arrester according to claim 4, wherein the bolt is a double-threaded bolt.