JP2018026449A - Arrestor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the bending strength or torsional strength of an arrestor.SOLUTION: In an arrestor 1, a plurality of zinc oxide elements 4 are laminated between a pair of electrodes 2, 3, the electrodes 2, 3 being fixed to each other by a support member 5. The support member 5 includes a core member and a FW layer formed by winding a FW (filament winding) material around the outer periphery of the core member. Holes are formed at both ends of the support member 5, respectively. One hole is hooked to a portion 2b to be hooked which is provided to the electrode 2, and the other hole is hooked to a portion 3b to be hooked which is provided to the electrode 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lightning arrester used for protecting an electrical device from an abnormal voltage that has entered a system. In particular, the present invention relates to a structure of a polymer lightning arrester in which a zinc oxide element unit is molded with a polymer insulating material such as silicone rubber.

  Lightning arresters are used to protect electrical equipment from abnormal voltages that have entered the system. For example, the lightning arrester is also used as a power transmission arrester main body for preventing a trip accident due to a lightning strike to a transmission line.

  As shown in FIG. 5, the direct mold type lightning arrester 9 is oxidized by a zinc oxide element unit 12 in which a zinc oxide element 4 which is a non-linear resistance element is laminated between electrodes 10 and 11, and a polymer insulating material such as silicone rubber. And a jacket 7 formed by directly molding the zinc element unit 12.

  A cage structure is mainly applied to the direct mold type lightning arrester 9. Specifically, a support member 13 is provided between the electrodes 10 and 11 so as to be disposed around the stacked zinc oxide elements 4. The support member 13 mechanically fixes the stacked zinc oxide elements 4 between the electrodes 10 and 11 and provides strength against bending moment. The support member 13 is formed of an insulator such as glass fiber reinforced plastic (FRP).

  The direct-mold type lightning arrester 9 is required to withstand a bending moment generated during an earthquake or a short-circuit current flowing during a short circuit, similarly to a lightning arrester using a porcelain insulator tube or a polymer insulator tube.

  Further, in the direct mold type lightning arrester 9, in order to prevent the polymer insulating material constituting the outer sheath from being intruded between the zinc oxide elements 4 and other parts that become conductive paths in the mold of the outer sheath 7, A compressive force is applied between the elements 4 by the pressing spring 14. And after installing as the lightning arrester 9, it receives the tension | tensile_strength of a lead wire (not shown), a wind pressure load, and the moment by an earthquake. Since these loads are mainly tensile loads on the support member 13 constituting the zinc oxide element unit 12, the strength of the support member 13 and the fixing strength between both ends of the support member 13 and the electrodes 10 and 11 are important factors. It becomes.

Japanese Patent Laid-Open No. 10-70013

  Glass fiber reinforced plastic (FRP) is a material in which a resin is reinforced with glass fibers and has excellent mechanical strength. However, the mechanical strength of the support member may be significantly reduced by performing processing such as cutting the glass fiber to fix the support member to the upper and lower electrodes.

  Therefore, in the lightning arrester according to the prior art, the electrodes are fixed by a belt-shaped wire ring (corresponding to a support member) (see, for example, FIG. 1 of Patent Document 1). The belt-shaped support member is formed of glass fiber and plastic bundled in one direction, and the glass fiber is oriented in the belt direction. Further, since the support member is in a belt shape, the glass fiber is not cut in order to fix the electrodes. Therefore, the belt-shaped support member has a structure advantageous to the tensile force generated by the bending load, and can exhibit the original strength of FRP.

  On the other hand, by making the support member into a belt shape, the center of the support member becomes a space, and the torsional rigidity of the support member itself is reduced, and as a result, the strength against the torsion of the lightning arrester is reduced. In order to improve the strength against the torsion of the lightning arrester, a reinforcing member can be attached to the outer periphery of the supporting member or the number of the supporting members can be increased. However, such reinforcement increases the cost of the lightning arrester.

  The belt-like support member is usually produced by winding glass fiber impregnated with epoxy resin around a mold (filament winding) and then curing the mold, and the mold is formed according to the length of the zinc oxide element unit. Necessary. That is, a mold is produced for each length of the zinc oxide element unit, and the manufacturing cost of the lightning arrester increases.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an inexpensive lightning arrester with improved bending strength and torsional strength.

  An aspect of the lightning arrester of the present invention that achieves the above object is to provide a stacked element having non-linear voltage-current characteristics, a pair of electrodes provided at both ends of the stacked element, and provided between the electrodes. A plurality of support members disposed around the element, and at least the element, the pair of electrodes, and a jacket made of a polymer insulating material that integrally molds the plurality of support members, The support member includes a core member, and a glass fiber reinforced layer formed on an outer peripheral portion of the core member and including glass fibers oriented in a direction along the outer periphery of the core member, and the electrode includes the electrode A stretched portion for stretching the support member between the electrodes is provided.

  Another aspect of the lightning arrester of the present invention that achieves the above object is that the lightning arrester projects at the end of the stretched part to the opposite side of the extending direction of the support member provided on the stretched part. A protruding edge portion is formed.

  According to the above invention, it is possible to manufacture an inexpensive lightning arrester having high bending strength and torsional strength.

(A) Side view of the main part of the lightning arrester according to the embodiment of the present invention, (b) Top view of the main part of the lightning arrester, (c) Bottom view of the main part of the lightning arrester, (d) FIG. It is AA sectional drawing of the lightning arrester shown in. (A) Top view of the electrode provided on the underside of the lightning arrester according to the embodiment of the present invention, (b) Side view of the electrode, (c) BB sectional view of the electrode shown in FIG. 2 (a) It is. (A) The top view of a supporting member, (b) CC sectional drawing of the supporting member shown to Fig.3 (a). (A) The enlarged view of the edge part of the core member which comprises a support member, (b) The enlarged view of the edge part of the support member before processing a hole, (c) The enlarged view of the edge part of a support member. It is sectional drawing which shows the outline of the lightning arrester which concerns on a prior art.

  The lightning arrester which concerns on embodiment of this invention is demonstrated in detail based on drawing.

  As shown in FIG. 1, a lightning arrester 1 according to an embodiment of the present invention includes a pair of electrodes 2, 3, a zinc oxide element 4 stacked between the electrodes 2, 3, and a periphery of the stacked zinc oxide elements 4. And a support member 5 disposed on the surface. Although not shown in FIG. 1, the lightning arrester 1 includes a zinc oxide element unit 6 in which a zinc oxide element 4 is laminated between the electrodes 2 and 3 in the same manner as the lightning arrester 9 according to the prior art shown in FIG. There are provided an outer member 7 directly molded with a polymer insulating material such as silicone rubber or an elastic member for applying a pressure contact force to the zinc oxide element 4. In the description of the embodiment, the side on which the electrode 2 is provided is the upper side and the side on which the electrode 3 is provided is the lower side with respect to the zinc oxide element unit 6, but the vertical direction does not limit the present invention in any way. Absent.

  The electrodes 2 and 3 are substantially cylindrical, and the end of the support member 5 is loosely fitted on the outer peripheral surface of the inner end of the electrodes 2 and 3 (that is, the end facing the zinc oxide element 4). Electrode grooves 2a and 3a are formed. The electrode grooves 2 a and 3 a are formed at substantially equal intervals according to the number of support members 5 provided in the zinc oxide element unit 6. In addition, the electrodes 2 and 3 can have not only a substantially cylindrical shape but also a prismatic shape having sides corresponding to the number of support members 5. As shown in FIG. 2B, a stretched portion 3 b that protrudes in the radial direction of the electrode 3 is provided on the surface of the electrode groove 3 a that faces the main surface of the support member 5. The stretched portion 3b is inserted into a hole 5a formed in the support member 5 described in detail later, and the support member 5 is hooked. Further, a protruding edge 3c is formed at the distal end of the stretched portion 3b and protrudes to the opposite side of the extending direction of the support member 5 provided on the stretched portion 3b. 3 is prevented from falling off in the radial direction. Similarly, the electrode 2 is provided with a stretched portion 2b protruding in the radial direction of the electrode 2 on the surface of the electrode groove 2a that faces the main surface of the support member 5, and the distal end of the stretched portion 2b. Is formed with a protruding edge 2c that protrudes to the opposite side of the extending direction of the support member 5 provided on the stretched portion 2b. Thus, the support member 5 is stretched between the electrodes 2 and 3 by hooking the end portions of the support member 5 to the stretched portions 2b and 3b.

  The zinc oxide element 4 has non-linear voltage-current characteristics. The zinc oxide element 4 functions as an insulator in the continuous use voltage of the lightning arrester 1 and functions as a conductor in a region where a voltage such as a lightning surge is large. This function makes it possible to protect the device from lightning surges. As shown in FIG. 1A, a length adjusting electrode 8 is provided between the zinc oxide element 4 and the electrode 2 (or electrode 3). One of the length adjustment electrodes 8 (for example, the length adjustment electrode 8 on the electrode 2 side) is abutted with a hexagon socket set screw, which will be described in detail later, and the length between the electrodes 2 and 3 is adjusted. .

  The support member 5 is stretched between the electrode 2 and the electrode 3. A plurality of support members 5 are provided between the electrodes 2 and 3. As shown in FIG. 3, a tension hole 5 a is formed at the end of the support member 5. As shown in FIG. 4, the support member 5 includes a plate-shaped core member 5b serving as a core, and an FW (filament winding) layer 5c formed on the outer periphery of the core member 5b (that is, the upper and lower sides and the side surface of the core member 5b). Have.

  The core member 5b is, for example, a plate formed of glass fiber reinforced plastic (FRP) or the like, and is formed at the corners of both ends of the core member 5b so that the FW material constituting the FW layer 5c is wound without any gap. Is chamfered (R-processed). The FW material is, for example, roving (glass fiber twisted yarn) impregnated with a matrix such as epoxy resin.

  The FW layer 5c is a layer formed by winding an FW material around the outer periphery of the core member 5b. The FW layer 5 c portion is a portion that bears the most important tensile strength (bending strength) in the support member 5. Therefore, the FW material is wound as many times as necessary to obtain a predetermined strength (so that the FW layer 5c has a thickness necessary to obtain the predetermined strength). As shown in FIGS. 4B and 4C, after the FW material is wound around the outer periphery of the core member 5b, the epoxy resin is cured. Then, the finally finished plate is sliced, and a hole 5a for stretching is opened, whereby the support member 5 is manufactured. In addition, the formation method of the hole 5a does not limit this invention at all. For example, the hole 5a can be formed in the core member 5b in advance, and the FW layer 5c can be formed in the core member 5b in which the hole 5a is formed.

  Even if a part of the glass fiber of the FW layer 5c is cut by opening the hole 5a, the glass fiber located outside the hole 5a is not cut. That is, since the glass fiber is not cut at the portion where the tension is actually received, the support member 5 having a predetermined strength can be obtained. Therefore, the hole 5a may be processed only in the core member 5b portion so as not to cut the glass fiber of the FW layer 5c, or may be processed so that the remaining portion of the FW layer 5c has a predetermined size.

  When the zinc oxide element unit 6 is manufactured, internal components such as the zinc oxide element 4 are disposed between the electrode 2 and the electrode 3, and the support member 5 is suspended between the electrode 2 and the electrode 3. Tension is applied to the support member 5, and the zinc oxide element unit 6 is assembled with the support member 5 extended. Thereby, compressive force is applied to the internal components such as the zinc oxide element 4 and the like, and between the zinc oxide elements 4 and between the zinc oxide elements 4 and the electrodes 2 and 3 (including the length adjusting electrode 8) in the mold of the outer cover 7. The polymer insulating material does not enter the.

  Here, the assembly method of the zinc oxide element unit 6 will be specifically described. First, the zinc oxide element 4 and the electrodes 2 and 3 at both ends are arranged side by side, and the end portion of the support member 5 is hooked on the stretched portions 2 b and 3 b of the electrodes 2 and 3. Next, the electrodes 2 and 3 at both ends are pulled by the assembling apparatus. Since the support member 5 extends, a gap is formed between the internal component (the zinc oxide element 4 or the length adjusting electrode 8) and the electrodes 2 and 3, but the gap is arranged on the electrode 2 (or electrode 3) on one side. The hexagonal socket set screw is turned and buried until the screw and the internal part (specifically, the length adjusting electrode 8) contact. Thereafter, when the tension is gradually applied, the support member 5 is extended and has a spring function. That is, the force that the support member 5 tries to contract becomes the compressive force.

[Torsional strength of support member 5]
The support member 5 and the belt-like wire ring of Patent Document 1 have different values of the cross-sectional secondary pole moment indicating the torsional rigidity of the member itself. Thereby, the ease of twisting of the zinc oxide element unit 6 also changes.

For example, the support member 5 having a thickness of 5 mm and a width of 25 mm has a secondary secondary pole moment of about 6770 mm ⁴ , whereas the wire ring thickness is 5 mm, the wire ring width is 5 mm, and the total wire ring width is 25 mm (there is no core member 5b). In the case) is about 5210 mm ⁴ . That is, when the support member 5 has a structure in which the FW layer 5c is formed on the core member 5b, the torsional rigidity of the member itself is improved by about 30%. As a result, the torsional rigidity of the zinc oxide element unit 6 and the lightning arrester 1 is improved.

  According to the lightning arrester 1 according to the embodiment of the present invention as described above, the lightning arrester 1 excellent in bending strength and torsional strength can be provided at a low cost.

  That is, in the support member 5 provided between the electrodes 2 and 3, at least the FW layer 5c has a structure in which glass fibers are continuous, and the original strength of the FRP can be expected. Moreover, since the fastening method by the screw normally used is not used, not only the original strength of FRP can be expected, but also the lightning arrester 1 can be easily assembled.

  Further, by increasing the torsional strength of the support member 5, it is possible to reduce the number of the support members 5 and to reduce the reinforcement members provided on the outer peripheral portion of the support member 5. As a result, the cost for reinforcing the lightning arrester 1 (and the zinc oxide element unit 6) can be reduced.

  Further, since the support member 5 is manufactured by winding the FW material around the core member 5b, a mold is not necessary, and the manufacturing cost of the lightning arrester 1 can be reduced. By eliminating the need for the mold, the mold release process is not required, and the trouble of manufacturing the lightning arrester 1 is reduced. Further, even when a commercially available FRP plate is used as the core member 5b, the bending strength and torsional strength are ensured by the FW layer 5c, so that the lightning arrester 1 that is inexpensive and excellent in bending strength and torsional strength can be provided. .

  Further, the length dimension of the support member 5 can be freely changed by changing the length of the core member 5b and the number of windings of the FW material (the degree of freedom in manufacturing the support member 5 in the length direction is great). That is, it is possible to reduce the cost and labor for producing the mold according to the length of the support member 5.

  Further, since the number of windings of the FW material, the orientation direction of the FW material, and the like can be freely selected according to the strength specification, the strength of the support member can be easily changed. Conventionally, a mold corresponding to a wire ring having a necessary width has been produced according to the strength specifications of the lightning arrester. However, in the lightning arrester 1 according to the embodiment of the present invention, the number of windings of the FW material is selected. Thus, the width and strength of the support member 5 can be freely changed. As a result, the manufacturing flexibility in the width direction of the support member 5 is increased, and the cost and labor for manufacturing the mold according to the width of the support member 5 can be reduced.

  Further, since the support member 5 is produced without cutting at least the glass fibers on the outer peripheral portion of the FW layer 5c, not only a bending strength equal to or higher than that of the belt-like support member is obtained, but also the center of the support member 5 is obtained. By providing the core member 5b at the portion, the torsional rigidity of the support member 5 itself is increased, and the torsional strength of the lightning arrester 1 (and the zinc oxide element unit 6) is greatly improved.

  As described above, the lightning arrester and the support member of the present invention have been described in detail by showing specific embodiments, but the lightning arrester and the support member of the present invention are not limited to the embodiment and are within a range not impairing the characteristics thereof. The design can be changed as appropriate, and the changed design also belongs to the technical scope of the present invention.

  For example, in the description of the embodiment, the FW layer 5c is formed on the core member 5b by filament winding (FW), but at least some of the glass fibers are in one direction (the direction along the outer circumferential direction of the core member 5b). As long as they are arranged, the FW layer is not limited to a layer formed by a filament winding method. For example, a glass fiber (glass cloth) may be wound around the outer periphery of the core member 5b so that a part of the glass fiber is oriented in one direction to form a layer similar to the FW layer 5c.

  Further, the stretched portions 2 b and 3 b provided on the electrodes 2 and 3 are not limited to the embodiment as long as the support member 5 can be stretched between the electrodes 2 and 3. For example, a method of machining female threads on the electrodes 2 and 3 and having a projection function with a set screw (preventing falling off is another method), or a method of passing bolts through the female threads formed on the electrodes 2 and 3 The support member 5 can be stretched between the electrodes 2 and 3.

  The element provided in the lightning arrester 1 is not limited to the zinc oxide element as long as it has non-linear voltage-current characteristics.

DESCRIPTION OF SYMBOLS 1 ... Lightning arrester 2, 3 ... Electrode 2a, 3a ... Electrode groove, 2b, 3b ... Stretched part, 2c, 3c ... Projection edge part 4 ... Zinc oxide element (element)
5 ... support member 5a ... hole, 5b ... core member, 5c ... FW layer (glass fiber reinforced layer)
6 ... Zinc oxide element unit 7 ... Coat 8 ... Length adjusting electrode

Claims (2)

A stacked element having non-linear voltage-current characteristics;
A pair of electrodes provided at both ends of the stacked elements;
A plurality of support members provided between the electrodes and disposed around the element;
And at least the element, the pair of electrodes, and a jacket made of a polymer insulating material that integrally molds the plurality of support members,
The support member includes a core member, and a glass fiber reinforced layer including glass fibers formed on an outer peripheral portion of the core member and oriented in a direction along the outer periphery of the core member,
The said electrode is equipped with the stretched part which stretches the said supporting member between the said electrodes, The lightning arrester characterized by the above-mentioned. 2. The lightning arrester according to claim 1, wherein a projecting edge portion is formed at an end portion of the stretched portion that protrudes in a direction opposite to an extending direction of a support member provided in the stretched portion.

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