JPH117853A - Current-limiting unit and current-limiting high-tension clamp insulator using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulating coating which has a high arc shielding effect without the insulation reduction caused by rainwater bridging and can minimize the influence on an adjacent insulator when it receives an excessive lighting surge. SOLUTION: A nonlinear resistant element 1 is connected and fixed to terminal metal fittings 2, 3 in series through a conductive paste 4 mainly composed of silver, and a plurality of elastic insulating coatings 5 having pleats 6 are applied to the circumference thereof. The diameters of the pleats 6 of the insulating coating 4 are successively reduced from the upper stage to the lower stage, whereby rainwater bridging is eliminated, and the flying of arc to parts other than an electrode is shielded. A thin part 7 formed of a gently curved surface is provided on one circumferential surface between the major diameter pleats 6, 6 in the upper part so as to be turned on the opposite side of a wire support insulator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current limiting device provided with an insulating coating used to protect a wire supporting insulator such as a high voltage clamp insulator or a high voltage tie top insulator of a distribution line from an arc generated by a lightning strike. The present invention relates to a unit and a current limiting type high pressure clamp insulator using the same.

[0002]

2. Description of the Related Art Conventionally, as a current limiting unit, a non-linear resistance element such as zinc oxide and a terminal fitting are joined and fixed in series, and a cylindrical insulating coating made of rubber or the like is provided on the outer periphery thereof. Used from. A current limiting unit having such a conventional insulating coating is disclosed in Japanese Patent Application Laid-Open No. 7-320577.
As shown in the publication, the diameter of the fold of the insulating coating was a constant cylindrical shape from the upper end to the lower end.

However, such a current limiting unit having a conventional insulating coating has the following problems. Since the diameter of the fold of the insulation coating is the same from the upper end to the lower end, during heavy rain such as thunderstorms, the rainwater flowing down from the tip of the upper fold reaches the tip of the lower fold, causing a bridge between the rainwater and insulation. May be reduced. Since the current limiting unit has a cylindrical shape, the effect of shielding the arc generated by lightning is small, and if the external discharge gap is set large, the lightning surge may occasionally fly to the side or base of the current limiting unit due to a sharp lightning surge. In some cases, the original function of the flow unit was not properly exhibited. The diameter of the fold of the insulating coating is the same from the upper end to the lower end, and the thickness of the insulating coating is also substantially uniform. For this reason, when an excessive lightning surge exceeding the capacity of the non-linear resistance element is received and high-temperature and high-pressure arc gas is generated from the non-linear resistance element due to the subsequent flow, the arc gas is ejected from an unspecified part and the adjacent insulator etc. There was a risk of damage.

[0004]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, does not cause a decrease in insulation due to bridging of rainwater, enhances an arc shielding effect, and strikes electric wire supporting insulators and electric wires by lightning. Equipped with an insulation coating that can reliably protect against arcs that occur and minimize the influence on adjacent insulators even if an excessive lightning surge exceeding the capacity of the nonlinear resistance element is received It is intended to provide a current limiting unit and a current limiting type high pressure clamp insulator using the same.

[0005]

According to the present invention, there is provided a current limiting unit having an insulating coating according to the present invention, wherein a non-linear resistance element and a terminal are joined and fixed in series.
A current limiting unit in which an elastic insulating coating having a plurality of pleats projecting around the outer periphery thereof is applied, and the diameter of the pleats of the insulating coating is gradually reduced from an upper stage to a lower stage, A thin wall portion having a smooth curved surface is provided on one outer peripheral surface between the upper large-diameter folds. Further, the current limiting type high pressure clamp insulator according to the present invention is characterized in that the above current limiting unit is attached to the side of the electric wire supporting insulator with its thin portion facing the opposite side of the electric wire supporting insulator.

In the current limiting unit having the insulating coating of the present invention, the diameter of the fold of the insulating coating is gradually reduced from the upper stage to the lower stage as described above. No bridging between the folds
A decrease in insulation due to a stormwater bridge is prevented. In addition, because the upper fold is large, it has an excellent shielding effect on the arc between the live part and the base that is the ground side during a flashover, and prevents the arc from flying to the side or the base of the current limiting unit. it can. In addition, since a thin portion composed of a smooth curved surface is provided on one outer peripheral surface between the upper large-diameter folds toward the opposite side of the wire support insulator, arc gas is supplied only from the thin portion to the opposite side of the insulator. There is an advantage that the gas can be reliably ejected and the influence on the adjacent insulator or the like can be minimized. Other advantages will be described with the following embodiments.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below. FIG. 1 is a cross-sectional view showing a first embodiment of a current limiting unit according to the present invention, wherein 1 is a non-linear resistance element mainly composed of zinc oxide, and 2 and 3 are terminal fittings. The non-linear resistance element 1 and the terminal fittings 2 and 3 are joined and fixed in series via a conductive paste 4 mainly containing silver. The upper terminal fitting 2 is an electrode for capturing an arc.

[0008] Reference numeral 5 denotes an insulating coating covering the outer periphery thereof.
The insulating coating 5 is made of a resilient material such as rubber, and has a plurality of pleats 6 projecting therearound. In the present invention, the diameter of the folds 6 of these insulating coatings 5 is gradually reduced from the upper stage to the lower stage so that the whole becomes an inverted truncated cone. Further, as shown in FIG. 2, a thin portion 7 having a smooth curved surface is provided on one outer peripheral surface between the upper large-diameter folds 6, 6, which will be described later. I do.

FIG. 3 is a view showing a current limiting type high pressure clamp insulator using the current limiting unit of the present invention. In FIG. 3, the current limiting unit of the present invention shown in FIG. 1 is vertically mounted near the wire supporting insulator 8 by the mounting bracket 9 so that the thin portion 7 faces the opposite side of the wire supporting insulator 8. The base of the mounting bracket 9 is fixed to the base of the electric wire support insulator 8 and the arm 10 of the utility pole, and the arm 11 of the mounting 9 supports the terminal metal 3 below the current limiting unit. A predetermined discharge gap G is formed between the cap fitting 12 of the electric wire supporting insulator 8 and the terminal fitting 2 on the current limiting unit.

When the insulator device shown in FIG. 3 receives a lightning strike, the lightning surge that has entered the electric wire 13 is flashed over by the discharge gap G, captured by the terminal fitting 2, passed through the non-linear resistance element 1, and grounded. Can be discharged to the side. When the lightning surge disappears, the non-linear resistance element 1 interrupts the continuation of the electric wire path, thereby preventing disconnection due to the arc and damage to the electric wire supporting insulator 8 as in the conventional case.

However, the current limiting unit of the present invention has an insulating coating 5
Since the diameter of the folds 6 is gradually reduced from the upper tier to the lower tier, the rainwater flowing down from the tip of the upper fold 6 falls downward without hitting the lower fold 6, and the lower fold 6
There is no bridge between them. For this reason, there is no decrease in insulation due to rainwater bridging, and creepage flashing of the insulating coating 5 is prevented.

Since the upper fold 6 has the maximum diameter and shields the arc, the arc from the cap fitting 12 of the electric wire supporting insulator 8 is reliably captured by the upper terminal fitting 2 projecting from the upper fold 6. can do. Therefore, it is possible to prevent the arc from flying to the side surface or the base of the current limiting unit as in the related art, and to exhibit the original function of the current limiting unit.

If the lightning surge is too large to exceed the capacity of the nonlinear resistor 1, the nonlinear resistor 1
Generates high-temperature and high-pressure arc gas. Therefore, the current limiting unit of the present invention has a large-diameter fold 6,
An arc gas is emitted in a certain direction by providing a thin portion 7 having a smooth curved surface on one outer peripheral surface between the wires 6 so as to face the opposite side of the wire supporting insulator 8. Thickness T ₁ of the thin wall portion 7 shown in FIG. 2, to be able to quickly open when high-temperature, high-pressure arc gas occurs, less than half and then, and the range of the thickness T ₀ of the cylindrical insulating cover 5 It is preferable that the thickness of the cylindrical insulating coating 5 is not more than half of the peripheral surface so as not to be vertically separated. Due to the thin portion 7, the cylindrical insulating coating 5 is broken at an unspecified position by the pressure of the arc gas as in the prior art, or the pieces of the terminal fittings 2, 3 and the non-linear resistance element 1 are separated from the installation location and fall. Can be prevented.

In particular, the current limiting unit of the present invention has an insulating coating 5
The diameter of the fold 6 is gradually reduced from the top to the bottom,
Since the thin portion 7 is provided on the upper part of the current limiting unit as shown in FIG. 1, the large-diameter folds 6 in the upper stage exert a flange effect,
Breakage of portions other than the thin portion 7 can be prevented. For this reason, even when an excessive lightning surge exceeding the capacity of the nonlinear resistance element 1 is received, the arc gas can be ejected in the direction from the thin portion 7 provided on the opposite side of the wire supporting insulator 8 in the direction. In addition to minimizing the influence on the insulators and the like, the collapse of the entire current limiting unit can be prevented by regulating the discharge location of the arc gas, and the terminal fittings 2 and 3 and the nonlinear resistance element 1 can be prevented. Can be prevented from falling to the surroundings. Note that the nonlinear resistance element 1
In the case of the multi-layer stacking, the position of the thin portion 7 can be shifted.

FIG. 4 is a sectional view showing a second embodiment of the current limiting unit according to the present invention, in which a joint between the nonlinear resistance element 1 and the lower terminal fitting 3 is protected by a reinforcing cap 14. Although different from the first embodiment, other points are almost the same as the first embodiment. This reinforcing cap 14
Is made of an insulating material such as plastics or ceramics, and has an effect of reliably guiding the arc gas generated from the non-linear resistance element 1 to the upper thin portion 7 when receiving an excessive lightning surge.

In any of the current limiting units of the above-described embodiments, the non-linear resistance element 1 and the terminal fittings 2 and 3 are joined and fixed via a conductive paste 4 mainly containing silver. As shown in the above-mentioned Japanese Patent Application Laid-Open No. Hei 7-320577, conventionally, a silver electrode is first baked on the non-linear resistance element 1 at a high temperature, and then the silver electrode and the terminal fittings 2 and 3 are soldered. Although the joining method has been adopted, this conventional method requires two heating steps. On the other hand, if a method is adopted in which the non-linear resistance element 1 and the terminal fittings 2 and 3 are joined and fixed via the conductive paste 4 containing silver as a main component,
Bonding in one step becomes possible.

The conductive paste 4 used is a mixture of silver powder and an organic binder such as an epoxy resin, which is applied to the polished end faces of the non-linear resistance element 1 as shown in FIG. At this time, for example, if a conductive paste is applied using a roller 16 or a squeegee or the like using a screen 15 made of a stainless steel wire mesh, it is possible to apply the conductive paste to a uniform thickness substantially similar to the wire diameter of the wire mesh.

The applied conductive paste 4 is heated to 150 ° C.
It may be fired at a low temperature of about × 40 to 60 minutes. FIG. 6 shows an example of an assembly jig 17 used for that purpose.
It has a structure in which a fastener 20 is provided between the seat plate 18 and the holding plate 19. As shown, a cushion 21 such as an asbestos sheet is placed on the seat plate 18, and the terminal fitting 3 is placed so as to be inserted into a hole of the seat plate 18. Next, the terminal fitting 2 is held down by the holding plate 19.
And then tighten with the fastener 20. As a result, a constant pressure is applied to the upper and lower conductive paste application surfaces of the non-linear resistance element 1, so that the paste may be set in a furnace to cure the paste. If the assembly jig 17 of FIG. 6 is used,
There is an advantage that a plurality can be fired simultaneously.

[0019]

As described above, the current limiting unit provided with the insulating coating of the present invention and the current limiting type high pressure clamp insulator using the same protect the wire supporting insulator and the wire from the arc generated by the lightning strike. Not only that, the diameter of the insulation coating folds is gradually reduced from the top to the bottom, which prevents insulation degradation due to rainwater bridging, and the upper large-diameter folds shield the arc. Excellent,
It is possible to prevent the arc from flying to the side surface or the base of the current limiting unit. In addition, the flange effect of the large-diameter pleats in the upper stage allows arc gas to be reliably ejected only from the thin portion to the opposite side of the insulator, and has the effect of minimizing the effect on adjacent insulators and the like. Therefore, the present invention is a current-limiting unit having an insulating coating that solves the conventional problems and a current-limiting high-pressure clamp insulator using the same,
It is of high value.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing a first embodiment of a current limiting unit of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partial sectional view showing a current limiting type high pressure clamp insulator of the present invention.

FIG. 4 is a sectional view showing a second embodiment of the current limiting unit of the present invention.

FIG. 5 is a perspective view showing a method of applying a conductive paste.

FIG. 6 is a partial sectional view of an assembly jig.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Non-linear resistance element, 2 upper terminal fittings, 3 lower terminal fittings, 4 conductive paste, 5 insulating coating, 6 folds, 7 thin portions, 8 wire support insulator, 9 mounting fittings,
DESCRIPTION OF SYMBOLS 10 Arm of telephone pole, 11 Arm of mounting bracket, 12 cap bracket, 13 electric wire, 14 reinforcing cap, 15
Screen, 16 rollers, 17 assembly jig, 18 seat plate, 19 holding plate, 20 fasteners, 21 cushion

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Kiyoshi Hasegawa 2-56, Suda-cho, Mizuho-ku, Nagoya, Aichi Prefecture Inside Nihon Insulators Co., Ltd. (72) Yoshinobu Noda 2-56, Suda-cho, Mizuho-ku, Nagoya-shi, Aichi No. Japan Insulators Co., Ltd. (72) Inventor Yuji Asai 2-56, Sudacho, Mizuho-ku, Nagoya City, Aichi Prefecture Inside Insulators Co., Ltd. (72) Tetsuya Asukai 2-56, Sudacho, Mizuho-ku, Nagoya City, Aichi Prefecture No. Japan Insulators Co., Ltd.

Claims (3)

[Claims] 1. A current limiting unit comprising a non-linear resistance element and a terminal fitting joined and fixed in series, and an outer periphery thereof provided with an elastic insulating coating having a plurality of pleats projecting therearound, The diameter of the fold of the insulating coating is gradually reduced from the upper tier to the lower tier, and a thin wall portion formed by a smooth curved surface is provided on one outer peripheral surface between the upper large-diameter folds. Current limiting unit provided with an insulating coating. 2. The non-linear resistance element and the terminal fitting are joined and fixed via a conductive paste mainly composed of silver.
A current limiting unit provided with the insulating coating according to item 1. 3. An electric wire supporting insulator according to claim 1, further comprising:
A current-limiting high-pressure clamp insulator, wherein the current-limiting unit according to any one of the preceding claims is mounted with its thin portion facing the opposite side of the wire supporting insulator.