JP2000100544A - Lightning arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an explosive breakage and avoid the scattering of fragments by easily releasing a pressure even when a current limiting element is broken and the internal pressure rises abruptly. SOLUTION: This lightning arrester is provided with a current limitning element 11 having nonlinear voltage-current characteristic and a pair of metal block-like terminal electrodes 12, 13 that are coaxially arranged with the current limiting element 11 pinched by the terminal electrodes 12, 13, and an insulating envelope body 16 fitted to this lightning arrester. Multiple insulating plates 19 fixed with end sections to the terminal electrodes 12, 13 and extended and bridged between both terminal electrodes 12, 13 are arranged along the outer periphery of the terminal electrodes 12, 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightning arrester, and more particularly to a lightning arrester attached to an insulator to protect peripheral equipment of a transmission and distribution line from a lightning surge when an abnormal voltage occurs due to a lightning surge or the like.

[0002]

2. Description of the Related Art Generally, when a lightning strike occurs near an insulator provided on a high-voltage or extra-high-voltage transmission and distribution line and an abnormal voltage is generated due to a lightning surge or the like, peripheral equipment of the transmission and distribution line is subjected to lightning surge or the like. For protection, a lightning arrester is installed between the ground side and the electric wire side of the insulator.

As shown in FIG. 12, this lightning arrester has a non-linear current-voltage characteristic having a low resistance to a surge voltage and a high resistance to a normal ground voltage of a transmission and distribution line.
It has a structure provided with a current limiting element 1 made of nO or the like. Specifically, a pair of metal block-shaped terminal electrodes 3 and 4 serving as a wire-side terminal and a ground-side terminal are fitted to both ends in the axial direction of the insulating tube 2 made of FRP and fixed by pins 5. The current limiting element 1 described above is housed and arranged between the two terminal electrodes 3 and 4 in the insulating cylinder 2. Further, it has a structure in which an insulating jacket 6 made of an elastic polymer or EPDM is attached to the outer peripheral surfaces of the insulating cylinder 2 and the terminal electrodes 3 and 4.

[0004] A compression spring 7 is inserted between the current limiting element 1 and the terminal electrode 3.
The current limiting element 1 and the two terminal electrodes 3 and 4 are brought into close contact with a predetermined compressive force to obtain a good bonding state.
And the terminal electrodes 3 and 4 are electrically connected.

The lightning arrester described above utilizes an insulator which is mounted on a support arm protruding in the lateral direction, which is disposed above a telephone pole, and which stands upright. Are attached by screws or the like, and a ring-shaped arc horn is attached to the upper end of the lightning arrester to form a predetermined discharge gap between the lightning arrester and the electric wire. The above-described insulator is supported by being fixed via a bind wire to an electric wire wired along an annular groove provided on the outer periphery of the top.

In this lightning arrester, when an abnormal voltage is generated due to a lightning surge or the like, the current limiting element 1 has a low resistance value and instantaneously escapes to the ground. If the abnormal voltage disappears, the current limiting element 1 becomes high. It becomes the resistance value and cuts off the normal ground voltage.
This valve action protects the peripheral equipment of transmission and distribution lines from lightning surges and the like.

[0007]

However, when a surge voltage exceeding the rating, such as a direct lightning strike, occurs, the current limiting element 1 may fail. In this case, the internal pressure in the closed space in the insulating jacket 6 is reduced. Rises sharply. Due to this sudden increase in internal pressure, the insulating cylinder 2 explosively breaks down together with the insulating jacket 6, and fragments thereof are scattered around. When such an explosive destruction of the lightning arrester occurs and its debris scatters, it causes a personal injury and is very dangerous and a serious problem.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to make it easy to release the pressure even if the current limiting element is broken and the internal pressure rises sharply. The purpose of the present invention is to prevent explosive destruction and to avoid the scattering of debris.

[0009]

As a technical means for achieving the above-mentioned object, the present invention provides a current limiting element having a non-linear voltage-current characteristic and a pair of metal block-shaped terminal electrodes on the same axis. A lightning arrester having a current limiting element sandwiched between terminal electrodes and having an insulating jacket attached thereto, the ends of which are fixed to the terminal electrodes, extend in the axial direction thereof, and are bridged between the terminal electrodes. A plurality of insulating plates are provided along the outer periphery of the terminal electrode.

In the surge arrester according to the present invention, as described above, the compressive force for sandwiching the current limiting element between the pair of terminal electrodes is held by the insulating plate, and the electrical and mechanical connection between the current limiting element and the terminal electrodes is maintained in a good condition. To maintain. Furthermore, since a plurality of the above-mentioned insulating plates are arranged along the outer periphery of the terminal electrode, the outer periphery of the current limiting element located between the terminal electrodes is only partially covered with the insulating plate. Even when the current limiting element is damaged due to the above and the internal pressure rises rapidly, the pressure can be easily released.

In addition, if a concave groove is formed in the outer peripheral surface of the terminal electrode so that the end of the insulating plate fits therein, even if a rotational force is applied in a direction substantially perpendicular to the axial direction at the time of mounting the lightning arrester, for example.
Since the position of the end of the insulating plate bridged between the two terminal electrodes is regulated by the concave groove, the strength in the twisting direction in the arrangement state of the current limiting element and the terminal electrode is improved. In addition, if the reinforcing metal is interposed between the current limiting elements, the above-described strength in the twisting direction is further improved.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lightning arrester according to the present invention will be described in detail below.

The lightning arrester of the embodiment shown in FIG. 1 has a non-linear current-voltage characteristic that exhibits a low resistance to surge voltage and a high resistance to a normal ground voltage of a transmission and distribution line.
It has only one current limiting element 11 made of O or the like. Metal block-shaped terminal electrodes 12, 13 are arranged at both axial ends of the current limiting element 11, and these terminal electrodes 12, 1
3 has a structure in which the current limiting element 11 is sandwiched. In addition, between the terminal electrodes 12 and 13 and the current limiting element 11, a coned disc spring 14 and a spacer 15
Is interposed. In addition, these two terminal electrodes 12, 13
In addition, an insulating jacket 16 made of silicon rubber or the like is attached to the outer peripheral surface of the current limiting element 11.

The lightning arrester of the embodiment shown in FIG. 2 has a plurality (three in the figure) of current limiting elements 11 arranged in series, and, like the embodiment of FIG. A disc spring 14 and a spacer 15 are interposed between the current limiting element 11 located at both ends and the terminal electrodes 12 and 13, and the outer peripheral surfaces of the terminal electrodes 12, 13 and the plurality of current limiting elements 11 are made of silicon rubber or the like. Is applied.

In this embodiment, a plurality of current limiting elements 11
A conductive bonding material 17, such as lead, is interposed between the bonding surfaces. The joining material 17 forms a layer between the joining surfaces of the current limiting element 11, but when assembling the current limiting element 11 and the terminal electrodes 12 and 13, a plurality of granular leads are scattered between the joining faces of the current limiting element 11. Then, by applying a compressive force while the current limiting element 11 is sandwiched between the terminal electrodes 12 and 13, the above-described granular lead is formed by spreading.

By thus interposing the conductive joining material 17 between the joining surfaces of the current limiting elements 11, the current limiting elements 11 can be mechanically and strongly joined to each other. In addition, when the insulating jacket 16 made of silicon rubber or the like is attached, the silicon rubber or the like does not enter between the joining surfaces of the current limiting element 11, so that the electrical connection between the current limiting elements 11 is good. And the desired device characteristics can be secured.

The current limiting element 11 as in this embodiment
Even when the conductive bonding material 17 is not interposed between the bonding surfaces, a structure like the lightning arrester of the embodiment shown in FIG. 3 can be adopted. The embodiment shown in FIG.
And a heat shrink tube 21 attached over the entire outer periphery of the substrate and a part of the outer periphery of the terminal electrodes 12 and 13. In addition to the heat-shrinkable tube 21, the current limiting element 11
In addition, any insulating tube that is in close contact with the outer periphery of the terminal electrodes 12 and 13 may be used.

In this way, the heat-shrinkable tube 21 is in close contact with the current-limiting element 11, so that the current-limiting elements 11 can be mechanically and strongly joined to each other. Current limiting element 1 when body 16 is applied
Since silicon rubber or the like does not intrude between the bonding surfaces of the first, the electrical connection between the current limiting elements 11 can be maintained in a good state, and desired element characteristics can be secured.

In addition to the insulating tube described above,
Although not shown, a structure in which an insulating material such as an epoxy resin is applied over the entire outer periphery of the current limiting element 11 and a part of the outer periphery of the terminal electrodes 12 and 13 by means such as coating to form a coating film. It is also possible.

Further, the lightning arrester of the embodiment shown in FIG. 4 has a plurality of (two in the figure) current limiting elements 11 arranged in series, and is the same as that of the embodiment of FIGS. Current limiting element 11 and terminal electrodes 12, 13 located at both ends in the axial direction.
A disc spring 14 and a spacer 15 are interposed between them, and an insulating jacket 16 made of silicon rubber or the like is attached to the outer peripheral surfaces of the terminal electrodes 12 and 13 and the plurality of current limiting elements 11.

The embodiment shown in FIGS. 1 and 2 is of the gapless type, while the embodiment shown in FIG. 4 is of the type having a gap, and is provided between the two current limiting elements 11 and between the current limiting element 11 and the terminal electrode. A series gap 18 is formed between 12 and 13 by a gap spacer (not shown).
By providing the three series gaps 18 in this manner, it is difficult for a leakage current to flow in a power-supplying state,
The applied voltage can be shared between the devices 2 and 13, and the voltage sharing can be made uniform.

In the lightning arrester in each of the above embodiments, a plurality of insulating plates 19 (for example, FRP) extending in the axial direction between terminal electrodes 12 and 13 located at both ends of the current limiting element 11 are provided.
Made). As shown in FIG. 5, for example, three insulating plates 19 are arranged at equal intervals of 120 ° along the outer periphery of the terminal electrodes 12 and 13, and are fixed to the terminal electrodes 12 and 13 by screws or the like. The insulating plate 19 can maintain a compressive force acting on the current limiting element 11 sandwiched between the terminal electrodes 12 and 13.

For example, if the width of the above-mentioned insulating plate 19 is about 1/6 of the entire circumference of the terminal electrodes 12 and 13, when the three insulating plates 19 are provided, the terminal electrodes 12 and 13 Of the entire circumference is covered with an insulating plate 19, and the other portions are merely covered with an insulating jacket 16 made of silicon rubber or the like. As a result, the current limiting element 1
In the case where 1 is broken, even if the internal pressure rises sharply, the above-mentioned pressure release from between the insulating plates 19 is easily performed. The insulating plate 19 is firmly attached to the terminal electrodes 12 and 13 by screws or the like.
2, 13 and the current limiting element 11 do not fall apart.

In the structure for attaching the insulating plate 19 to the terminal electrodes 12 and 13, a concave groove 20 is formed on the outer peripheral surface of the terminal electrodes 12 and 13, and the end of the insulating plate 19 is fitted into the concave groove 20. It is preferable to use a structure in which screws are used.

With such a structure of fitting the end portion of the insulating plate 19, the strength against the rotational force applied in a direction substantially perpendicular to the axial direction is improved. Thereby, even if a rotational force acts in a direction substantially perpendicular to the axial direction when the lightning arrester is mounted, the strength in the twisting direction is improved in the arrangement state of the terminal electrodes 12, 13 and the current limiting element 11.

Further, as described above, the end of the insulating plate 19 is fitted into the concave groove 20 of the terminal electrodes 12 and 13, so that the insulating plate 19 does not protrude as much as its plate thickness, and the lightning arrester can be reduced in size. It becomes easy. If the depth of the groove 20 'is slightly larger than the thickness of the insulating plate 19 as shown in FIG. 6, the above-mentioned miniaturization can be further facilitated without the insulating plate 19 protruding completely. Further, if the outer surface of the insulating plate 19 'is formed into a curved surface similar to the outer peripheral surfaces of the terminal electrodes 12, 13 as shown in FIG.

Further, as shown in FIG. 8, if the width of the bottom surface of the concave groove 20 ″ is slightly larger than the width of the opening surface so as to have a reverse tapered cross section, the insulating plate 19 ″ can be axially moved. Since the mounting method of inserting is possible and the insulating plate 19 ″ does not detach in the radial direction, the fixing means is not limited to screwing, but is pin fixing for restricting removal in the axial direction. Is also possible.

The lightning arrester of the embodiment shown in FIG.
It has a structure in which a reinforcing metal fitting 22 is interposed between two current limiting elements 11 in a state of being in close contact with the joining surface of the current limiting elements 11. As shown in FIGS. 10 and 11, the reinforcing metal fitting 22 has grooves 20, 20 'and 20''formed on the outer peripheral surface thereof, and insulating grooves (not shown) are formed in the grooves 20, 20' and 20 ''. The plate 19 (see FIG. 5) fits.

As described above, the reinforcing bracket 22 is provided between the current limiting elements 11.
The strength against the rotational force applied in a direction substantially perpendicular to the axial direction is further improved as compared with the case where only the insulating plate 19 is interposed. Thereby, even if a rotational force acts in a direction substantially perpendicular to the axial direction when the lightning arrester is mounted, the strength in the twisting direction is further improved in the arrangement state of the terminal electrodes 12, 13 and the current limiting element 11.

[0030]

According to the present invention, a plurality of insulating plates whose ends are fixed to the terminal electrodes and extend in the axial direction and are bridged between the two terminal electrodes are provided along the outer periphery of the terminal electrodes. The state in which a compressive force is applied to the current limiting element between the two terminal electrodes can be held by the above-mentioned insulating plate, and the electrical and mechanical connection of the current limiting element can be kept good, and high quality element characteristics can be maintained. Can be maintained. In addition, since there is a gap between multiple insulating plates, even if the current limiting element breaks and the internal pressure rises sharply, the pressure is easily released, and explosive destruction is prevented and debris is scattered. Can be easily realized.

Further, by forming a concave groove on the outer peripheral surface of the terminal electrode into which the end of the insulating plate is fitted, even if a rotational force is applied in a direction substantially perpendicular to the axial direction at the time of mounting the lightning arrester, etc.
Since the position of the end of the insulating plate bridged between the two terminal electrodes is regulated by the concave groove, the strength in the twisting direction in the arrangement state of the current limiting element and the terminal electrode is increased, and the quality can be improved. If a reinforcing bracket is interposed between the current limiting elements, the above-described strength in the twisting direction is further improved, and a high-quality lightning arrester can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a gapless type lightning arrester having one current limiting element according to an embodiment of the present invention;

FIG. 2 is a sectional view showing a gapless type lightning arrester having three current limiting elements according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a gapless type lightning arrester to which a heat-shrinkable tube is added according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a lightning arrester with a gap in which three series gaps are formed according to another embodiment of the present invention.

FIG. 5 is a sectional view showing an insulating plate attached to a terminal electrode.

FIG. 6 is a partial sectional view showing a concave groove of a terminal electrode and an insulating plate;

FIG. 7 is a partial cross-sectional view showing another example of a concave groove of a terminal electrode and an insulating plate.

FIG. 8 is a partial cross-sectional view showing the concave groove of the terminal electrode and another cross-sectional shape of the insulating plate.

FIG. 9 is a sectional view showing a gapless type lightning arrester according to another embodiment of the present invention, in which a reinforcing bracket is interposed between current-limiting elements.

FIG. 10 is a plan view showing an example of the reinforcing bracket of FIG. 9;

FIG. 11 is a plan view showing another example of the reinforcing fitting of FIG. 9;

FIG. 12 is a sectional view showing a conventional lightning arrester.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Current limiting element 12, 13 Terminal electrode 16 Insulation jacket 19 Insulation plate 20 Depression groove 22 Reinforcement metal fitting

Claims (3)

[Claims] 1. A current-limiting element having a non-linear voltage-current characteristic and a pair of metal block-shaped terminal electrodes are arranged coaxially, and an insulating jacket is covered with the current-limiting element sandwiched between the terminal electrodes. A lightning arrester characterized in that a plurality of insulating plates whose ends are fixed to a terminal electrode, extend in the axial direction thereof, and are bridged between both terminal electrodes are arranged along the outer periphery of the terminal electrode. . 2. The lightning arrester according to claim 1, wherein a concave groove is formed in an outer peripheral surface of each of the terminal electrodes located at both ends of the current limiting element, into which an end of an insulating plate is fitted. 3. The lightning arrester according to claim 2, wherein a reinforcing bracket is interposed between said current limiting elements.