JPH11121139A - Arrester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance performance regarding the discharge withstand current rating by suppressing a creeping flashover on the surface of a track current limiting element. SOLUTION: Bottoms of recessed plate-like connecting fittings 17, 18, each having a rising part extended from the periphery of the bottom, are bonded to both ends of current limiting elements 11, 12 made of ZnO or the like having a nonlinear volt-ampere characteristic that shows a low resistance to a surge voltage and a high resistance to a normal voltage-to-ground of a transmission line, respectively, a prepreg sheet 19 made by infiltrating a thermoset resin into insulating cloth made of a nonconductive fiber is wound throughout the outside peripheral surfaces of the track current limiting elements 11, 12 and the rising parts of the connecting fittings 17, 18, and the current limiting elements 11, 12 and the connecting fittings 17, 18 integrated together by being covered with the prepreg 19 is received in an insulating cylindrical body 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 for protecting peripheral equipment of a transmission and distribution line from a lightning surge when an abnormal voltage is generated due to a lightning surge or the like.

[0002]

2. Description of the Related Art Generally, when a lightning strike occurs near a high-voltage or extra-high power transmission and distribution line or when an abnormal voltage is generated due to a lightning surge or the like, the transmission and distribution line equipment is protected from lightning surge or the like. A lightning arrestor is installed between the ground side and the wire side of the wire.

As shown in FIG. 3, this lightning arrester has a nonlinear voltage-current 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 current limiting elements 1 and 2 such as O. The current limiting elements 1 and 2 are housed in an insulating cylindrical body 3 made of porcelain, and the terminal electrodes 4 and 5 on the electric wire side and the ground side are attached to the opening portions at both ends of the insulating cylindrical body 3. Current limiting elements 1 and 4
And a sealed space 6 is formed in the insulating cylindrical body 3 by the electric wire side terminal electrode 4 and a seamer fitting 8 described later.

The illustrated surge arrester has two current limiting elements 1 and 2.
2 are stacked in the axial direction, and connection fittings 7 are provided at both upper and lower ends thereof.
And a structure in which the seamer fitting 8 is joined to each other.
Of the two current limiting elements 1 and 2, the upper current limiting element 1 is electrically connected to the wire-side terminal electrode 4 via the connection fitting 7 and another internal element 9 arranged above it. The current limiting element 2 located on the lower side is electrically connected to the ground-side terminal electrode 5 via the seam fitting 8 and the support fitting 10.

In this lightning arrester, when an abnormal voltage occurs due to a lightning surge or the like, the current limiting elements 1 and 2 have a low resistance value and instantaneously escape to the ground, and if the abnormal voltage disappears,
The current limiting elements 1 and 2 have a high resistance value and cut off the normal ground voltage. This valve action protects transmission and distribution line equipment from lightning surges and the like.

[0006]

However, in the above-mentioned conventional lightning arrester, since the current limiting elements 1 and 2 are housed in the closed space 6 in the insulating tubular body 3, the current limiting elements 1 and 2 are not provided. 2, the limit processing energy for a large current having a short waveform (several μs to tens of μs) such as a lightning surge is affected by the dielectric strength of the air layer, and a current limiting element is provided. At present, it has been difficult to make full use of the original performance possessed by the technicians.

Further, when assembling the internal elements of the surge arrester, when the current limiting elements 1 and 2 and the connecting metal 7 and the seamer metal 8 located above and below the current limiting elements 1 and 2 are displaced, If the current-limiting elements 1 and 2 are displaced from each other, the contact area between the current-limiting elements 1 and 2 and the connection fitting 7 and the seam fitting 8 and the contact area between the current-limiting elements 1 and 2 decrease. As a result, the electrical performance is reduced and it is difficult to obtain the desired performance.

Accordingly, the present invention has been proposed in view of the above problems, and an object of the present invention is to provide a surge arrester capable of suppressing creeping flashes on the surface of a current limiting element and improving the performance with respect to discharge capability. Is to provide.

[0009]

SUMMARY OF THE INVENTION As a technical means for achieving the above object, the present invention relates to a current limiting element having a non-linear voltage-current characteristic. Joining the bottom of the concave dish-shaped connection fitting having a portion,
A prepreg sheet obtained by impregnating an insulating cloth made of a non-conductive fiber with a thermosetting resin is wound around the entire outer peripheral surface of the rising portion of the current limiting element and the connection fitting, and the outer peripheral surfaces of the current limiting element and the connection fitting are prepreg. It is characterized by being covered with a sheet.

[0010] In the present invention, it is preferable that the bottom of the concave dish-shaped connection fitting is joined to both ends of the current limiting element along the axial direction.

[0011]

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

The lightning arrester of this embodiment has a non-linear voltage / current having a low resistance to a surge voltage and a high resistance to a normal ground voltage of a transmission / distribution line as shown in the overall structure of FIG. Current limiting elements 11 and 12 (two in the figure) made of ZnO or the like having characteristics are stacked and arranged coaxially.
12 are housed in an insulating cylindrical body 13 made of porcelain, and the wire-side and ground-side terminal electrodes 14 and 15 electrically connected to the current limiting elements 11 and 12 are placed in the openings at both ends of the insulating cylindrical body 13. It has a structure in which a sealed space 16 is formed in the insulating tubular body 13 by being attached and the electric wire side terminal electrode 14 and a seamer fitting 21 described later.

In the illustrated embodiment, the two current limiting elements 11 and 12 are arranged in the axial direction.
The present invention is not limited to this, and can be applied to a structure in which one or three or more current limiting elements are housed.
Further, in addition to the structure in which the current limiting elements 11 and 12 are housed in the insulating cylindrical body 13 made of porcelain and the closed space 16 is formed in the insulating cylindrical body 13 as in the above-described embodiment, the current limiting elements The present invention is also applicable to a structure in which an insulating jacket made of an elastic polymer, EPDM, or the like is adhered to the outer periphery of the flow element in a state of being in close contact therewith.

At the upper and lower ends of the current limiting elements 11 and 12 along the axial direction, as shown in FIG.
7, 18 are joined. These concave dish-shaped connection fittings 17 and 1
Reference numeral 8 denotes bottoms 17a, 18a having substantially the same shape and area as the end faces of the current limiting elements 11, 12, and the bottoms 17a, 1
Standing portions 17b, 18 extending in the axial direction from the periphery of 8a
b. The connection fitting 17 may be joined only to the upper end of the current limiting element 11 located on the upper side, and the connection fitting 18 joined to the lower end of the current limiting element 12 located on the lower side is necessarily required. is not.

The current limiting elements 11 and 12 and the connection fitting 1
The prepreg sheet 19 is wound around the outer circumference of the wrappers 7 and 18.
Specifically, the prepreg sheet 19 uses, for example, high-strength non-conductive fibers made of glass fiber or the like as warps along the axial direction, and low-strength non-conductive fibers made of, for example, polyester fiber or the like in the axial direction. Insulating cloth made of weft yarns extending in the orthogonal radial direction is impregnated with an insulating thermosetting resin such as an epoxy resin or a polyester resin.

Connection fittings 17 and 18 are joined to upper and lower ends of the current limiting elements 11 and 12 along the axial direction, and a predetermined pressure is applied from the connection fittings 17 and 18 toward the current limiting elements 11 and 12. In the state, the current limiting elements 11 and 12 and the connection fitting 1
The prepreg sheet 19 described above is wound around the entire outer peripheral surfaces of the upright portions 17b and 18b of the uprights 7 and 18. The prepreg sheet 19 is adhered in a state of being in close contact with the current limiting elements 11 and 12 and the connection fittings 17 and 18 due to the heat shrinkage of the weft yarn by the heat treatment. 18 are integrated.

Prepreg sheet 1 made of this insulating material
9, the current limiting elements 11 and 12 and the connection fittings 17 and 18
Is covered with the entire outer peripheral surface thereof, it is difficult for moisture to enter the inside thereof, and the current limiting elements 11 and 12 and the connection fittings 17 and 1 are not covered.
8 has an effect of suppressing the occurrence of partial discharge at the joint portion with No. 8 and leading to creeping flashover. In particular, since the shape of the connection fittings 17 and 18 is a concave dish shape, the connection fittings 1 and 18 are formed by the upright portions 17 b and 18 b of the connection fittings 17 and 18.
7 has an effect of also suppressing creeping flashover due to partial discharge at a joint portion between the bottom portion 17a and the spacer fitting 20 and a joint portion between the bottom portion 18a of the connection fitting 18 and the seamer fitting 21.

The current limiting elements 11 and 12 and the connection fitting 1
7 and 18 are integrated by the prepreg sheet 19, so that when assembling the internal elements of the lightning arrester, the current limiting elements 11 and 12 and the connecting metal fittings 17 and 18 located above and below them are used.
When the current limiting elements 11 and 12 are plural, the desired performance of the current limiting elements 11 and 12 can be obtained without causing positional offset between the current limiting elements 11 and 12. it can.

The prepreg sheet 19 of this embodiment
Is an insulating cloth composed of a high-strength warp and a low-strength weft, but in addition to this, for example, non-conductive fibers having different thicknesses between the warp and the weft, or By forming a close-packed state in the arrangement relationship between the warp yarns and the weft yarns, it is possible to obtain an insulating cloth in which the transverse strength is lower than the longitudinal strength. Further, the non-conductive fibers of the warp and the non-conductive fibers of the weft may be either the same type of fiber or different types of fiber.

Further, since the above-mentioned connection fittings 17 and 18 have a concave dish shape, they have an effect of preventing displacement of internal components located above and below them. That is, a spacer fitting 20 is fitted into the connection fitting 17 joined to the upper end of the current limiting element 11 located on the upper side, and a seamer fitting is attached to the connection fitting 18 joined to the lower end of the current limiting element 12 located on the lower side. By fitting 21, there is no displacement between the two.

In addition, above the connection fitting 17 joined to the upper end of the current limiting element 11 located on the upper side, the above-mentioned spacer fitting 20, the electrode fitting 22, the gap spacer 23,
The electric wire side terminal electrode 14 is attached with a sealing rubber 26 by bolting or the like via a spring 24 with a lead plate and a buffer plate 25. A support fitting 29 is fixed below the connection fitting 18 joined to the lower end of the current limiting element 12 located below by a silicone 27 and cement 28 via the seamer fitting 21 described above. The ground-side terminal electrode 15 is led out from 29.

In the surge arrester according to the present invention, when an abnormal voltage is generated due to a lightning surge or the like, the current limiting elements 11 and 12 have a low resistance value and instantaneously escape to the ground. The elements 11 and 12 have a high resistance value and cut off the normal ground voltage. This valve action protects transmission and distribution line equipment from lightning surges and the like.

At this time, since the current limiting elements 11 and 12 and the connection fittings 17 and 18 are covered with the prepreg sheet 19, as described above, the creeping flashes at the current limiting elements 11 and 12 and the connection fittings 17 and 18 are performed. It has the effect of suppressing the occurrence of entanglement. Further, since the current limiting elements 11 and 12 and the connection fittings 17 and 18 are integrated by the prepreg sheet 19, the current limiting element 1
Positioning of the current limiting elements 11 and 12 with the connection fittings 17 and 18 and the current limiting elements 11 and 12 can be performed, and desired performance of the current limiting elements 11 and 12 can be obtained.

Further, since the shape of the connection fittings 17 and 18 is concave, the internal elements located above and below the connection fittings 17 and 18 are positioned by fitting.
Current limiting elements 11 and 12 with prepreg sheet 19 attached
In addition, alignment between the connection fittings 17 and 18 and other internal elements becomes easy.

[0025]

EXAMPLE The applicant of the present invention conducted a discharge resistance test on the product of the present invention and a conventional product. This discharge tolerance test is referred to as a lightning impulse large current test. A lightning arrester using a current limiting element for a discharge current of 2500 A has a discharge current waveform of 4/30.
The test current of 10 μs was changed to 10 kA, 20 kA, 30 kA,
. Are supplied twice stepwise at predetermined time intervals (for example, 5 minutes).

The results of this test show that the conventional product provided only a discharge withstand of 50 kA, while the product of the present invention provided a discharge capacity of 7 kA.
The discharge withstand capability of 0 to 80 kA was obtained, and the improvement of the discharge withstand capability of about 1.5 times was realized. As a result, the discharge current 2500
The lightning arrester using the current limiting element for A will have performance comparable to the lightning arrester using the current limiting element for 5000A.

[0027]

According to the present invention, since the current limiting element and the connection fitting are covered with the prepreg sheet, a partial discharge is generated from the joint between the current limiting element and the connection fitting, and the air layer near the current limiting element is generated. Can be suppressed from extending to the creepage flash. Due to the suppression of the creeping flash, the original performance of the current limiting element can be sufficiently exhibited, and the electrical performance with respect to the discharge withstand capability can be improved. In addition, since the shape of the above-mentioned connection fitting is a concave dish shape, an effect of suppressing creeping flashover due to partial discharge from the bottom of the connection fitting is exerted by the rising part of the connection fitting.

Further, since the current limiting element and the connection fitting are integrated by the prepreg sheet, the positioning of the current limiting element, the connection fitting, and the current limiting element can be performed when assembling the internal elements of the lightning arrester. The desired performance can be obtained, and the electrical performance can be improved also in this regard.

Further, since the shape of the connection fitting is a concave dish shape, the internal elements located above and below the connection fitting are positioned by fitting, and the current limiting element and the connection fitting with the prepreg sheet attached thereto are formed. Alignment with other internal elements is facilitated, and good assemblability is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an arrester according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the overall configuration of the arrester of the present invention

FIG. 3 is a sectional view showing an example of a conventional lightning arrester.

[Explanation of symbols]

 11, 12 Current-limiting element 17, 18 Connection fitting 17a, 18a Bottom part 17b, 18b Standing part 19 Pre-preg sheet

Claims (2)

[Claims] 1. A current limiting element having a non-linear voltage-current characteristic, wherein the bottom of a concave dish-shaped connection metal fitting having an upright portion extending from the bottom peripheral edge is joined to an end of the current limiting element. A prepreg sheet impregnated with a thermosetting resin in an insulating cloth made of a non-conductive fiber was wound around the entire outer peripheral surface of the rising portion of the connection fitting, and the outer peripheral surfaces of the current limiting element and the connection fitting were covered with the prepreg sheet. A lightning arrester characterized by the above. 2. The lightning arrester according to claim 1, wherein the bottom of said concave dish-shaped connection fitting is joined to both ends along the axial direction of said current limiting element.