JP3546576B2 - Surge arrester - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an arrester, and more particularly to an arrester having an insert coated with an insulating polymer material.
[0002]
[Prior art]
The current surge arrester basically includes a sintered body mainly composed of zinc oxide as a characteristic element (hereinafter, referred to as a ZnO element) and upper and lower electrodes for sandwiching the ZnO element and supplying current to the ZnO element. And an insulating container for integrally forming the ZnO element and the upper and lower electrodes and enclosing the insulating container, and a jacket for covering the insulating container.
[0003]
This lightning arrester is installed on power transmission, distribution line or protection equipment, and protects these lines or equipment from abnormal voltage.Conventionally, porcelain porcelain insulators have been used as outer jackets. In addition, in recent years, instead of porcelain insulator tubes, fiber-reinforced plastics (hereinafter abbreviated as FRP) having excellent mechanical strength, heat resistance, and pressure resistance are used instead of porcelain insulators. A so-called "insulating cylinder" is formed by covering an outer periphery thereof with a rubber jacket (hereinafter abbreviated as "jacket") such as an insulating polymer material having good weather resistance, for example, EPDM (EP rubber) or silicon (rubber). The development of polymer arresters is underway.
[0004]
FIG. 6 is a cross-sectional view of a main part of an integrated structure of the electrode and the ZnO element of the polymer surge arrester. Reference numerals 1 and 2 denote upper and lower electrodes. Both electrodes are formed in a columnar shape. , Circumferential grooves 1a and 2a are provided.
[0005]
Reference numeral 3 denotes a ZnO element. The ZnO element 3 is made of a sintered body mainly composed of zinc oxide as a characteristic element of the lightning arrester, and is used in a single or a plurality in series according to the rated voltage of the lightning arrester. You. Reference numeral 4 denotes a pressure contact spring, which is elastically mounted between one end of the ZnO element 3 and the upper electrode 1 via the electrode plate 5, and presses the ZnO element between the ZnO element and the upper and lower electrodes.
[0006]
Reference numeral 6 denotes a moisture-proof tape, which is directly wound around the entire outer peripheral surface of the ZnO element 3 and a part of the outer peripheral surfaces of the electrodes 1 and 2 with the press-contact spring 4 interposed therebetween so that moisture infiltrates the ZnO element 3. To prevent
[0007]
Reference numeral 7 denotes a pressure-resistant insulating tube which is obtained by winding a resin-impregnated tape (prepreg tape) impregnated with FRP resin and heat-curing the resin-impregnated tape. And 2a and the electrode steps 1b and 2b are tightly wound without providing a gap, and are formed by heating and curing. Reference numeral 8 denotes an electrode supporting means for holding the electrodes 1 and 2 so that the electrodes 1 and 2 do not pop out when the internal pressure rises. A resin impregnated tape is wound around the grooves 1a and 2a as reinforcement, and the pressure-resistant insulating cylinder 7 is heated. Heat curing at the same time as curing. Alternatively, it is compressed and held by a compression fitting. These ZnO elements 3 and electrodes 1 and 2 are integrated by a pressure-resistant insulating cylinder 7 to form an insert 10.
[0008]
The lightning arrester is configured by mounting a jacket on the outer periphery of the insert 10. As means for mounting, there are two methods as shown in FIG.
[0009]
7A and 7B are conceptual diagrams of a lightning arrester for explaining mounting means. FIG. 7A shows a method called an integral molding method, in which an insert 10 is integrally molded with a jacket 11.
[0010]
FIG. 2B shows a so-called slip-on system, in which a jacket 12 and an insert 10 are separately formed, and the jacket 12 is hermetically supported by grippers 13 and 14, so that a gap between the jacket 12 and the insert 10 is obtained. Is filled with an encapsulant 15 such as silicone rubber.
[0011]
[Problems to be solved by the invention]
The advantage of the integral molding method is that the outer casing is integrally molded with the insert, so that the sealing property or adhesion between the outer casing and the insert is good. It is less susceptible to electrical performance degradation due to entry.
[0012]
On the other hand, there are disadvantages such as the occurrence of defects due to the load on the insert during molding of the jacket, the discard of a healthy insert due to the defective molding of the jacket, and the like, resulting in poor product yield and high product cost.
[0013]
Further, in the slip-on method, since the outer cover and the insert are separately molded and the insert is covered with the outer cover, it is possible to solve the disadvantages of the load and yield on the insert, which are disadvantages of the integral molding method.
[0014]
On the other hand, as a disadvantage, it takes time to cover the jacket.
[0015]
However, the slip-on method is preferable from the viewpoint of the structure of the jacket, manufacturing cost, or prevention of functional deterioration of the ZnO element.
[0016]
When this slip-on system is used, there are the following problems to be solved.
[0017]
(1) Prevention of outflow of the encapsulant (2) Ensuring easy installation of the jacket (3) Prevention of falling off of the jacket In particular, the problems (2) and (3) pursue conflicting performances. In FIG. 7B, in order to solve the problems (1) to (3), both ends of the electrode are fixed by gripping tools. In this case, depending on the shape of the gripping tool, the outer shape may be reduced. Depending on the material of the jacket or the material of the jacket, stress relaxation may occur during long-term use, and the material may fall off, and the problem (3) cannot be solved.
[0018]
The present invention has been made to solve these problems in the slip-on system.
[0019]
[Means for Solving the Problems]
In the present invention, a means for solving the above-mentioned problem is to separately provide an insert in which a ZnO element and an electrode are integrally formed by a pressure-resistant insulating cylinder, and a jacket made of an insulating polymer material covering the outer periphery of the insert. Formed in the lightning arrester, which is mounted on the insert, and the gap between the insert and the outer cover is filled with an encapsulant.
A circumferential fitting groove is provided on each of the upper and lower portions of the insert, and a circumferential protrusion is provided on the outer cover so as to elastically fit into each of the fitting grooves. The fitting groove is fitted elastically. Further, a tapered portion having a large diameter in the direction of insertion of the jacket is provided in each of the upper and lower portions of the insert, and the jacket is provided with a projection having a tapered hole joined to each of the tapered portions. The tapered hole of the part is joined to the tapered part of the insert to be mounted. Furthermore, a circumferential fitting groove is provided in the tapered portion of the insert having the tapered portion, and the outer jacket is elastically fitted into the fitting groove in addition to the protrusion having a tapered hole joined to the tapered portion. A circumferential projection is provided, the projection is elastically fitted into the fitting groove, and the jacket is hermetically supported by both the joining of the tapered portion and the fitting of the projection.
[0020]
The mounting of the insert jacket is performed simply by using the elasticity of the jacket to fit into the groove or joined to the tapered part. Prevention of falling off can be easily realized.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the embodiments shown in FIGS. 6 and 7 are denoted by the same reference numerals, and description thereof is omitted.
[0022]
FIGS. 1A and 1B are explanatory views of a first embodiment of the present invention, in which FIG. 1A is a front view in which a jacket is sectioned, and FIG.
[0023]
In the present embodiment, the fitting grooves 1c and 2c in the circumferential direction are provided in the upper part and the lower part of the insert 10, for example, in a part of the outer periphery of the electrodes 1 and 2, respectively. Are provided with annular projections 21 and 22, respectively, which are fitted into the fitting grooves 1c and 2c to seal the inside.
[0024]
This mounting means utilizes the elasticity of the jacket. That is, the inner diameters of the protrusions 21 and 22 are smaller than the outer diameters of the electrodes 1 and 2 and are equal to or slightly larger than the outer diameters of the bottoms of the fitting grooves 1c and 2c. When a projection having a small inner diameter is inserted, the projection is expanded by elasticity and easily deformed to have a thickness capable of slipping and inserting around the outer periphery of the electrode, and the width of the fitting groove is elastically fitted in accordance with this thickness.
[0025]
In this manner, the jacket 20 is fitted and fitted into the fitting grooves 1c, 2c by utilizing the elasticity of the rubber of the projections 21, 22, and the upper and lower sides are sealed, and then the sealing provided in the jacket in advance is provided. An encapsulant 15 such as silicone rubber is filled from a material insertion portion (not shown), and the insertion portion is sealed.
[0026]
The shape of the fitting groove of the mounting portion and the shape of the protrusion fitted to the fitting groove are not necessarily limited to a rectangular cross section. The cross section may be triangular as shown in FIG. 2A or may be elliptical in cross section as shown in FIG.
[0027]
FIGS. 3A and 3B are explanatory views of a second embodiment of the present invention, in which FIG. 3A is a front view of a cross section of a jacket, and FIG.
[0028]
In this embodiment, the outer diameter of the upper electrode 1 and the lower electrode 2 is set to be smaller for the former and larger for the latter, and the outer circumference of the electrodes 1 and 2 is inserted in the direction in which the jacket is inserted (FIG. 3). Tapered portions 1d and 2d having a large diameter (from the top to the bottom) are provided, and the jacket 30 is provided with projections 31 and 32 having insertion holes corresponding to the outer shapes of the electrodes 1 and 2. Then, the outer cover 30 is inserted from the upper electrode 1 having the smaller outer diameter and pushed down strongly, and the insert 10 and the outer cover 30 are strongly attached to the insert 10 by the elasticity of the outer cover.
[0029]
In addition, the insertion hole which is joined to the tapered portion of the upper electrode by the projection of the jacket is a tapered hole corresponding to this electrode. In addition, the tapered portion 2d of the lower electrode 2 may be provided only on the upper end side so that the protrusion 32 can be easily inserted as shown in FIG. Good.
[0030]
FIGS. 4A and 4B are explanatory views of a third embodiment of the present invention, in which FIG. 4A is a front view in which a jacket is sectioned, and FIG.
[0031]
In this embodiment, the first embodiment and the second embodiment are used in combination. The outer periphery of the upper electrode 1 is a tapered portion 1d, the fitting groove 1c is provided on the outer periphery of the intermediate portion, and the lower electrode 1 is provided with a fitting groove 1c. The electrode 2 has a tapered portion 2d on the inner side, a fitting groove 2c provided on the outer periphery of the intermediate portion, and a tapered portion having an insertion hole at the upper part of the jacket 40 for joining with the tapered portion 1d of the small-diameter electrode 1. A mounting portion 41 comprising a joining portion 41a and a groove fitting portion 41b fitted in the fitting groove 1c is provided, and a fitting 42a to which the large-diameter electrode 2 is joined and a fitting groove 2c are fitted below. A mounting portion 42 is provided which includes a groove fitting portion 42a and a groove fitting portion 42b fitted into the fitting groove 2c. To mount the jacket 40 on the insert 10, insert the electrode 1 from the mounting portion 42 side of the jacket 40, push down in the direction of the arrow to fit the lower projection 42 b into the fitting groove 2 c and the upper projection 41 b into the fitting groove 2 c. It fits into the fitting groove 1c.
[0032]
In this embodiment, the jacket is supported and the airtightness is maintained by the mounting force at both the joint surface of the taper and the projection and the fitting groove. Therefore, the connection between the insert and the jacket becomes stronger, and the fall of the jacket is more reliably prevented.
[0033]
FIG. 5 shows an example of the shape of the jacket mounted on the insert, in which a plurality of pleats H are added to increase the creepage distance of the jacket. Whether to use the sheath with the folds or the sheath without the folds is appropriately selected and used depending on the rated voltage of the lightning arrester, the place of use, and the like.
[0034]
【The invention's effect】
As described above, the present invention provides a fitting groove or a tapered portion in the upper and lower portions of the insert, and the outer jacket is provided with a protrusion or a mounting portion fitted or joined to the fitting groove or the tapered portion, Since the mounting of the jacket to the insert is performed by elastically fitting or joining the protrusions of the jacket to the fitting grooves or tapered portions of the insert, the mounting of the jacket becomes extremely easy, and The outflow can be completely prevented, and the fall of the jacket can be prevented, so that all the problems of the slip-on system can be solved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a first embodiment of the present invention.
FIG. 2 is an explanatory view of a fitting means of FIG. 1;
FIG. 3 is an explanatory diagram of a second embodiment of the present invention.
FIG. 4 is an explanatory diagram of a third embodiment of the present invention.
FIG. 5 is an external view of an embodiment of a jacket of the present invention.
FIG. 6 is a sectional view of a main part of the insert.
FIG. 7 is a conceptual diagram of a conventional lightning arrester.
[Explanation of symbols]
1, 2, electrodes 1c, 2c fitting groove 3, ZnO element 4, press-contact spring 5, electrode plate 6, moisture-proof tape 7, pressure-resistant insulating cylinder 8, electrode support means 10, inserts 11, 12, 20, 30, 40 ... Enclosure 15... Encapsulating materials 21, 22, 31, 32.

Claims (3)

An insert in which a ZnO element and an electrode are integrally formed by a pressure-resistant insulating cylinder, and a jacket made of an insulating polymer material covering the outer periphery of the insert are separately formed, and this jacket is attached to the insert, and the insert and In a lightning arrester consisting of an encapsulant filled in the space created between the jackets,
A circumferential fitting groove is provided in each of the upper and lower portions of the insert, and a circumferential protrusion is provided in the outer cover to elastically fit in the respective fitting groove. A lightning arrester characterized by being fitted elastically in a mating groove. An insert in which a ZnO element and an electrode are integrally formed by a pressure-resistant insulating cylinder, and a jacket made of an insulating polymer material covering the outer periphery of the insert are separately formed, and a rubber jacket is mounted on the insert, and In a lightning arrester formed by filling an encapsulant into a gap generated between rubber jackets,
In each of the upper and lower portions of the insert, a tapered portion having a large diameter in the direction of insertion of the jacket is provided, and the jacket is provided with a projection having a tapered hole that is joined to at least the upper tapered portion. A lightning arrester characterized in that a tapered hole is attached to and attached to a tapered portion of the insert. A circumferential fitting groove is provided on each tapered portion of the insert, and a circumferential protrusion is provided on the outer jacket to elastically fit into each of the fitting grooves. The lightning arrester according to claim 2, wherein the lightning arrester is elastically fitted.

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