JPH0454664Y2 - - Google Patents

Description

[Detailed description of the invention] Purpose of the invention (industrial application field) This invention relates to a cutout that protects a transformer and prevents accidents on electric lines, and particularly relates to a cutout that has a built-in lightning arrester unit.

(Prior Art) Conventionally, there has been a cut-out structure as shown in FIG. 10 in which a lightning arrester unit is housed within the main insulator. This is a stepped portion 81b having a through hole 81a integrally formed at the lower end of the porcelain storage cylinder 81.
On the other hand, the flange portion 83a of the electrode fitting 83 constituting the gap unit 82 is supported, and the terminal portion 83
b was led out to the outside from the through hole 81a. or,
The gap unit 82 was provided with a discharge electrode 84 on the upper part of an insulating cylinder 86, and a discharge electrode 85 on the upper surface of the flange portion 83a. Furthermore, a non-linear resistor unit 8 is provided above the gap unit 82.
8 was stored.

(Problem that the invention aims to solve) However, in the conventional cutout, surface insulation resistance decreases due to deterioration over time, and surface flash shorting occurs in the gap unit 82 during lightning surge discharge, causing damage to the lightning arrester unit. The discharge starting voltage and the discharge voltage characteristics of the gap unit 82 may fluctuate, or due to an excessive lightning surge, the non-linear resistor unit 88 may be damaged and a follow-on arc may flow, resulting in the pressure impact of high-temperature, high-pressure gas. As a result, there was a problem in that the housing tube 81 was damaged and the arc penetrated into the fuse tube housing portion, thereby increasing damage to the cutout.

The purpose of this invention is to provide a cutout that solves the above problems.

Structure of the invention (means for solving the problem) In order to solve the above-mentioned problem, this invention uses a fuse that connects or opens between the fixed electrodes on the power supply side and the load side, which are provided in the main body insulator made of porcelain. In the cutout having a cylinder, a housing cylinder having a bore is integrally formed in the main body insulator, a gap unit and a non-linear resistor unit are connected in series and housed in the bore, and the gap unit is connected to the housing cylinder in series. It is connected to the fixed electrode on the load side, and the external opening edge of the storage cylinder is sealed with a cap fitting that can release pressure, and the outer circumferential surface of the insulating cylinder constituting the gap unit is oriented toward the fixed electrode side. The inner circumferential surface of the storage cylinder is formed into a tapered surface, which was previously formed into a tapered surface with a small diameter, so that it almost coincides with this tapered surface, and an insulator is interposed between both tapered surfaces for adhesion and pressure reception. A method of supporting the gear unit is adopted.

(Function) In this invention, the storage cylinder is provided with a tapered surface, and the tapered surface provided on the outer periphery of the insulating cylinder constituting the gear unit is supported by interposing an insulator, so lightning surge discharge of the gear unit is supported. At this time, the pressure impact is transmitted to the tapered surface of the insulating cylinder and the tapered surface of the housing cylinder by a wedge action and compresses the insulator, so that the joint interface between the circumferential surface of the insulating cylinder and the housing cylinder The insulation is strengthened to prevent surface flashovers and stabilize the gap unit's discharge voltage characteristics. Even if a follow-on current occurs, the pressure impact is dispersed on the tapered peripheral surface, so stress concentration is suppressed, the accommodating cylinder is prevented from breaking, and the arc does not enter the fixed electrodes.

(Example) The first example that embodies this idea will be described below.
This will be explained in detail with reference to FIGS.

As shown in Fig. 3, a power supply side electrode chamber 3 and a load side electrode chamber 4 are formed inside the main body insulator 1 made of porcelain, which are separated by partition walls 2, 2. The electrodes 5, 6 and the arc extinguishing chambers 7, 8 are embedded and fixed at their base end portions with a filler 9. Connection terminals 10 and 11 are attached to the fixed electrodes 5 and 6, respectively, and are connected to a power supply side lead wire and a load side lead wire (not shown), respectively.

An insulating cover 12 is pivotally attached to the open side (lower side in FIG. 3) of the main body insulator 1 so that it can be opened and closed, and inside the insulating cover 12 there are a pair of electrodes connected or opened between the fixed electrodes 5 and 6. A fuse tube 13 provided with contact blades 13a and 13b is removably attached.

A storage cylinder 14 is integrally formed in the center of the back side (upper side in FIG. 3) of the main insulator 1, and a lumen 14a is formed inside the storage cylinder 14. The inner lumen 14
a is open at its upper part, and is opened between the partition walls 2 and 2 at its lower part, and communicates with the load-side electrode chamber 4 through a guide hole 2a provided in the load-side partition wall 2. Further, an annular stepped portion 14b having an opening having an inner diameter smaller than the upper opening is formed on the inner circumferential surface of the inner cavity 14a. This stepped portion 14b
The inner peripheral surface of the storage tube 14 located on the upper side has a tapered surface 14 that becomes smaller in diameter toward the fixed electrodes 5 and 6.
It is formed in c.

Inside the bore 14a are a lower conductive unit 15, a gap unit 16, and a gap unit 16 constituting a lightning arrester unit.
A non-linear resistor unit 17 and an upper conductive unit 18 are housed in this order.

Therefore, the gap unit 16 and the nonlinear resistor unit 17 will be explained with reference to FIGS. 1 and 2.

As shown in FIG. 1, the gap unit 16 includes an insulating cylinder 19 made of an inorganic material such as alumina porcelain, and a thin plate electrode 20 made of molten metal is adhesively fixed to the upper end surface by silver soldering or the like. An upper discharge electrode 21 is welded to the lower surface of the center. The outer peripheral surface of the insulating cylinder 19 has a tapered surface 1 similar to the tapered surface 14c of the storage cylinder 14.
9a is formed. Further, a pressure-resistant electrode plate 22 made of, for example, an Fe-Ni alloy is adhesively fixed to the lower surface of the insulating cylinder 19 with silver wax, and a lower discharge electrode 23 is welded to the upper surface of the central portion thereof. In this embodiment, the gap unit 16 is composed of the insulating cylinder 19, the thin plate electrode 20, the voltage-resistant electrode plate 22, the discharge electrodes 21 and 23, and the like. A threaded cylinder 24 is provided on the lower surface of the center of the voltage-resistant electrode plate 22, into which a conductive rod 35 of the lower conductive unit 15, which will be described later, is screwed.
is fixed.

A thermal strain prevention ring 25 made of an inorganic material such as alumina porcelain is fixed to the lower surface of the voltage-resistant electrode plate 22 by silver brazing or the like, and the insulating cylinder 19
The thermal stress caused by the difference in thermal expansion coefficient between the voltage-resistant electrode plate 22 and the voltage-resistant electrode plate 22 is alleviated, the voltage-resistant electrode plate 22 is prevented from curving, and the adhesive surfaces of both 19 and 22 are prevented from peeling and the insulating cylindrical body is prevented from being damaged. There is. A flat washer 2 is provided between the thermal strain prevention ring 25 and the stepped portion 14b.
6 and cushion material 27 are interposed.

Rings made of closed foam rubber or the like are provided between the upper outer circumferential surface of the insulating cylinder 19 and the inner circumferential surface of the inner cavity 14a of the storage cylinder 14, and between the outer circumferential surface of the voltage-resistant electrode plate 22 and the tapered surface 14c. 28 and 29 are fitted. Further, an insulating material 30 such as urethane rubber or low melting point glass is provided between the tapered surface 14c and the outer peripheral surface of the gear unit 16, the rings 28, 29, the thermal strain prevention ring 25, the flat washer 26, and the cushion material 27. Filled.

The nonlinear resistor unit 17 includes a predetermined number of cylindrical nonlinear resistor elements 31 made of zinc oxide (ZnO), and electrode plates 32 are provided on the upper and lower surfaces of the nonlinear resistor elements 31 and between them. are arranged and joined together. The non-linear resistor unit 17 is connected in series to the gap unit 16 via the lower electrode plate 32.
The outer peripheral surface of the non-linear resistor unit 17 is EPR.
The inner cavity 14a is insulated and enclosed by a heat-shrinkable tube 33 mainly made of (ethylene propylene rubber) or a silicone rubber tube with excellent heat resistance.
An insulating material 34 such as urethane rubber is filled in some gaps formed between the circumferential surfaces.

Next, the lower conductive unit 15 attached to the threaded tube 24 will be explained based on FIG.
A seal fitting 37 is fitted through the seal fitting 37, and an O-ring 38 is interposed between the upper surface of the seal fitting 37 and the lower surface of the stepped portion 14b. The seal fitting 37 is attached to the lower end of the conductive rod 35 with the disc spring 3.
9 and a nut 41 that presses upward via the spring holder 40 is screwed together. Further, a lead wire 43 for connecting the lower conductive unit 15 to the load-side fixed electrode 6 is attached to the lower end of the conductive rod 35 by a screw 42. Note that the inner cavity 1
An insulator 44 is filled in the lower part of 4a.

Next, the upper conductive unit 18 will be explained. The unit 18 is arranged above the non-linear resistor unit 17 in the inner cavity 14a, and the conductive cylinder 45 constituting the unit 17 has a small diameter cylindrical portion 45a. The bottom plate part 45b includes a bottom plate part 45b formed on the lower outer periphery of the cylindrical part 45a, and a peripheral wall part 45c protruding from the outer periphery of the bottom plate part 45b.
The electrode plate 32 of the nonlinear resistor unit 17
is joined to. The upper end opening of the cylindrical portion 45a is hermetically closed with a lid 46 made of lead, copper, or the like. Further, the insulator 34 is also filled between the conductive cylinder 45 and the inner peripheral surface of the inner cavity 14a.

A seal ring 47 is attached to the upper end of the storage tube 14.
A spring conductor 50 whose upper and lower ends are connected by a flexible conductor 49 between the cap metal fitting 48 and the bottom plate portion 45b of the conductive tube 45, which are caulked together through
is interposed.

The cap metal fitting 48 has a thin metal plate such as a copper plate with a cap-shaped central surface protruding from its central surface so that it can bulge and deform due to the internal gas pressure caused by the short-circuit current arc when the follow-on current cannot be interrupted and release the pressure. It is formed with a notch (not shown) for breaking the hole, etc. Further, it is preferable that the discharge electrodes 21 and 23 are made of thin metal plates such as a low melting point alloy, and are appropriately provided with a notch so that they can be dissolved or broken by gas.

A terminal fitting 52 for connecting a grounding wire 51 is provided on the upper surface of the cap fitting 48. A clamp plate 53 is tightened and fixed to one side of the terminal fitting 52 by bolts 54, and the clamp plate 53 and the terminal fitting 52 are tightened and fixed.
A grounding wire 51 is clamped between. Further, the other end of the grounding wire 51 is fixed to a grounding conductor such as a metal arm (not shown). Furthermore, the terminal fitting 52 has a horizontal portion 52a that is adhesively fixed to the cap fitting 48, and a vertical portion 52b that is orthogonal to the horizontal portion 52a.
The horizontal part 52a is bifurcated, and
The boundary between both parts 52a and 52b is a bendable part 52c. Then, due to the abnormally high pressure inside the storage tube 14, the cap metal fitting 48 comes off and separates from the storage tube 14 as shown in FIG. 4, or a part of the cap metal fitting 48 breaks as shown in FIG. When detached, the vertical portion 52b connects to the bendable portion 5.
2c, and absorbs the impact on the ground wire 51 due to the movement energy of the cap metal fitting 48, thereby preventing the cap metal fitting 48 from flying off due to breakage of the ground wire 51.

Next, the operation of the cutout configured as described above will be explained.

In the present invention, the inner peripheral surface of the storage cylinder 14 and the insulating cylinder 1
Tapered surfaces 14 each have an inclination angle α on the outer peripheral surface of 9.
c, 19a are provided, and an insulator 30 is interposed between both tapered surfaces, and the gap unit 16 has an insulating cylindrical body 19 that connects the fixed electrodes 5, 6 as shown in FIG.
Since it is supported by the tapered surface 14c of the stepped portion 14b against the side, when the inside of the gap unit 16 is discharged due to a lightning surge, the reaction force of the pressure impact acts on the insulators interposed between the tapered surfaces 14c and 19a. Press it to strengthen the insulation on the surface of the gap unit 16.

That is, the insulating cylinder 1 of the gap unit 16
The reaction force (pressure) F acting on 9 is due to the wedge action, and becomes F=F1sinα+F2cosα =F1sinα+F1・μ・cosα, where F1 is the drag force in the vertical direction to the tapered surface,
F2 is the drag force parallel to the tapered surface. Here, if the friction coefficient μ between the tapered surfaces 14c and 19a is set to zero and its influence is conveniently removed, F≒F1sinα, and the drag force F1 in the vertical direction to the tapered surface is:
Approximately 1/1 of the pressure F caused by discharge
Since it acts as sin α, the tapered surfaces 14c, 1
Sufficient compressive force can be obtained for the insulator interposed between 9a.

If the inclination angle α becomes smaller, the tapered surface 14c
In practice, it is desirable to set the inclination angle α to about 10 to 30 degrees because the vertical resistance against the inclination increases. In this case, the vertical drag force on the tapered surface 14c
F1 will be about 2.0F to 6.0F, but the tapered surface 14c
Due to the pressure-receiving area of , the distributed stress per unit area toward the main insulator 1 side becomes minute, and therefore there is no need to increase the wall thickness of the main insulator 1.

Furthermore, as mentioned above, the compressive shock generated in the gap unit 16 is dispersed on the circumferential surface of the housing tube 14 to prevent damage due to stress concentration, so even if a follow-on arc occurs, both the fixed electrodes 5, 6 Otherwise, it does not enter the fuse cylinder 13 side.

Next, a second embodiment of the present invention will be described based on FIG. 6.

In this embodiment, the stepped portion 14 of the storage cylinder 14
b is omitted, and the lead wire 43 is fixed to the threaded cylinder 24 with a screw 42. Moreover, the tapered surface 1
4c and the tapered surface 19a of the insulating cylindrical body 19, a cushion material 63 as an insulator made of, for example, an asbestos joint sheet coagulated with rubber is interposed.

In the second embodiment, since the step portion 14b and the lower conductive unit 15 can be omitted, the structure can be simplified compared to the first embodiment, but the other structure and operation are the same as in the first embodiment. The same is true.

Next, a third embodiment of the present invention will be described based on FIG.

In this embodiment, a bottom part 19b is integrally formed with the lower end of the insulating cylinder 19 instead of the voltage-resistant electrode plate 22, and an electrode rod 64 is inserted into a mounting hole penetrated through the center of the bottom part 19b. A lower discharge electrode 23 is fitted to the upper end. Further, a threaded cylinder 24 is screwed into the lower end of the electrode rod 64.
4 is fixed to the bottom portion 19b by silver paste or brazing. A conductive rod 35 of the lower conductive unit 15 is screwed into the lower part of the threaded cylinder 24.

Furthermore, the formation of the horizontal surface of the stepped portion 14b provided in the storage tube 14 is omitted to form the tapered surface 14c,
A cushion material 65 as an insulating material such as rubber is interposed. Although this third embodiment can also simplify the structure of the main insulator 1, other structures and functions are the same as those of the first embodiment.

Next, a fourth embodiment of the present invention will be described based on FIG. 8.

In this embodiment, the gap unit 16
A thin plate electrode 66 is used in place of the voltage-resistant electrode plate 22, and the structure of the lower conductive unit 15 is such that the seal fitting 37 is integrally formed with the conductive rod 35, and the stepped portion 14b is formed on the upper part of the conductive rod 35. A dish-shaped washer 67 that is brought into contact with the upper surface is fitted, a nut 68 is screwed onto the upper end of the conductive rod 35, and the gap unit 16 is placed on the upper end surface of the dish-shaped washer 67.

In this fourth embodiment, the structure of the lower conductive unit 15 can be simplified, but other structures and functions are similar to those in the first embodiment.

Here, an application example in which the structure of the tapered surfaces 14c and 19a, which are the main parts of the cutout of the present invention, is implemented in a lightning arrester will be described based on FIG. 9.

In this application example, a gap unit 16 is built in the upper end of a cylindrical insulator tube 71 made of an insulating material such as glass or rubber, and a nonlinear resistor unit 17 is built in the lower part of the gap unit 16. Conductive unit 1 similar to unit 18
A cap fitting 48 is attached via 8'.
A high voltage side lead wire 72 is connected to the exposed upper end portion of the conductive rod 35 .

In this application example, as in the previous example, the discharge impact of the gap unit 16 can strengthen the surface insulation of the gap unit 16 and prevent damage to the insulator tube 71.

Effects of the invention As detailed above, this invention strengthens the surface insulation of the gap unit by using the pressing force generated on the gap unit during lightning surge discharge, so it improves the discharge starting voltage and discharge voltage characteristics of the lightning arrester unit. In addition to stabilization, the pressure shock is dispersed over the circumferential surface of the accommodating portion of the gap unit, which has the effect of preventing damage to the insulating container.

[Brief explanation of the drawing]

Figure 1 is a sectional view of only the main parts of a cutout embodying this idea, Figure 2 is a sectional view of a lightning arrester unit attached to the cutout, Figure 3 is a sectional view of the entire cutout, Figures 4 and 3 are sectional views of the cutout as a whole. Figure 5 is a partial cross-sectional view showing the cap metal fittings in a destroyed state, and Figures 6 to 8 are cross-sectional views of only the main parts showing second to fourth embodiments of the present invention as cutouts. 9 is a longitudinal cross-sectional view of the central part showing an example in which the present invention is applied to a lightning arrester, and FIG. 10 is a partial cross-sectional view showing a storage structure of a gap unit in a conventional example. 1... Main body insulator, 5, 6... Fixed electrode, 13...
... Fuse cylinder, 14 ... Storage cylinder, 14a ... Inner cavity, 14b ... Stepped part, 14c, 19a ... Tapered surface, 15 ... Lower conductive unit, 16 ... Gap unit, 17 ... Nonlinear resistor unit, 1
8... Upper conductive unit, 19... Insulating cylinder, 1
9b... Bottom, 21, 23... Upper (lower) discharge electrode, 22... Voltage resistant electrode plate, 24... Screw tube, 3
0...Insulator, 31...Nonlinear resistance element, 35
... Conductive rod, 45 ... Conductive tube, 48 ... Cap fitting, 63, 65 ... Cushion material as an insulator, F ... Reaction force, F1 ... Reaction force in the vertical direction to the tapered surface, F2 ... Taper Horizontal drag force on the surface, α...Inclination angle of the tapered surfaces 14c, 19a.

Claims (1)

[Scope of Claim for Utility Model Registration] In a cutout provided with a fuse tube 13 for connecting or opening fixed electrodes 5 and 6 on the power supply side and the load side provided in the main insulator 1 made of porcelain, Storage cylinder 1 having a cavity 14a
A gap unit 16 and a non-linear resistor unit 17 are connected in series and housed in the bore 14a.
is connected to the fixed electrode 6 on the load side, and the external opening edge of the housing cylinder 14 is sealed with a cap fitting 48 that can release pressure, and the outer peripheral surface of the insulating cylinder 19 constituting the gap unit 16 is sealed. ,
A tapered surface 19a becomes smaller in diameter toward the fixed electrode 5.6 side, and the inner circumferential surface of the storage cylinder 14 is formed into a tapered surface 14c so as to be substantially coincident with this tapered surface 19a.
A cutout characterized in that the gap unit 16 is supported by interposing insulators 30, 63, 65 for adhesion and pressure reception between the tapered surfaces 14c and 19a.