JPH0533805B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Object of the Invention [Field of Industrial Application] This invention relates to a method of manufacturing a high-voltage capacitor used for electric power.

[Prior art] So-called wound capacitors, in which a plastic film is used as a dielectric material and a metallized film on which a metal is deposited are stacked and wound, are used for electric power because they are non-polar and have low dielectric loss. used for. However, when used under high voltage, corona discharge tends to occur at both ends of the winding, and improvements in dielectric strength characteristics are required.

By the way, the high-voltage capacitor (conventional example 1) described in Japanese Utility Model Application Publication No. 59-107131 was devised to solve the above-mentioned problem, and as shown in FIG. The elements 24 are connected in series and parallel to each other, and SF ₆ is housed in the outer container 25.
There is a high-voltage capacitor (conventional example 2) that is filled with an insulating gas such as gas.

The high-voltage capacitor of Conventional Example 1 is constructed by filling an insulating gas into a capacitor element formed by integrally winding an electrode and a dielectric, and further surrounding the outer periphery of this capacitor element with a flame-retardant synthetic resin part. ,
Furthermore, it has a structure in which terminals from electrodes are led out on the outer surface of this synthetic resin part, and this high voltage capacitor is manufactured generally by the following manufacturing method.

First, metallized films are stacked and wound up in the air, metal is thermally sprayed on both end faces of the wound element to form electrodes, and lead wires are connected to these electrodes to obtain a capacitor element.Next, A plurality of the obtained capacitor elements are assembled, placed in a mold, and subjected to vacuum drying treatment.The vacuum mold is filled with insulating gas, and the insulating gas is injected into the gap between both ends of the winding of each capacitor element. After that, a flame-retardant synthetic resin liquid is injected while maintaining the insulating gas inside the mold at a positive pressure state, the synthetic resin liquid is heated to a curing temperature, and after the curing reaction, the mold is removed and the high-voltage capacitor is taken out. It is used.

The high-voltage capacitor produced by the manufacturing method of Conventional Example 1 can be expected to have a slight amount of insulating gas stagnation in the irregularities on both ends of the windings of each capacitor element, and has poor corona discharge characteristics compared to a capacitor element in which the capacitor element is not filled with insulating gas. This has the advantage of improving dielectric strength and improving dielectric strength at the same time. Moreover, the conventional example 2 has the advantage that corona discharge characteristics are improved by sealing an insulating gas in the outer container 25.

[Problems to be Solved by the Invention] However, in the high-voltage capacitor manufactured by the manufacturing method of Conventional Example 1, the metallized films are stacked and wound in the atmosphere, so air is trapped between the wound metallized films. There is a problem in that air voids exist between them.

Even if each capacitor element with such air voids is vacuum-dried, it is possible to remove air and moisture from the irregularities on both winding end faces of each capacitor element, but the air and moisture present between the metallized films can be removed. There is a problem in that the air voids present cannot be removed by this vacuum drying process.

Furthermore, when embedding each capacitor element injected and filled with insulating gas under a positive pressure state into a synthetic resin liquid, the winding of each capacitor element is The insulating gas that had accumulated in the uneven parts of both end faces gains buoyancy from the synthetic resin liquid, and some of it flows out as bubbles in the synthetic resin liquid, and the synthetic resin liquid is heated to the curing reaction temperature. During the initial stage of curing, the viscosity of the synthetic resin liquid decreases, and the remaining insulating gas is warmed and becomes more buoyant, which causes bubbles to form in the synthetic resin liquid and escape to the outside. . Therefore, there is a problem in that it is difficult to expect much of the insulating gas to remain in the uneven portions on both ends of the winding of each capacitor element.

In addition, in the structure of Conventional Example 2, the insulating gas sealed in the outer container 25 leaks from the joint between the container body 25a and the lid body 25b forming the outer container 25, or from the attachment part of the bushing 26. The insulating gas pressure within 25 may drop. When the insulating gas pressure decreases, the insulation of the capacitor element 24 decreases, and there are problems in that moisture and the like from the outside enter through the airtight leakage area and deteriorate the capacitor element.

Therefore, this invention starts corona discharge by allowing SF ₆ gas to accumulate at high density in the weak points of dielectric strength around the edges of the metal thin film on both ends of the winding of the capacitor element and the weak points of dielectric strength due to voids between the metallized films. The present invention aims to provide a manufacturing method for obtaining a high-voltage capacitor having a structure that is resistant to hermetic leakage of insulating gas in order to improve the voltage and maintain this performance for many years.

(b) Structure of the invention [Means for solving the problems] In order to solve the above problems, this invention has the following features:
First, a process of winding a metallized film, which is a metal thin film formed on a plastic film, in an SF ₆ gas atmosphere, a process of forming electrodes on both end faces of the element in the air, and connecting lead wires to the electrode. A process in which the capacitor element with a lead wire connected is housed in an inner container and subjected to vacuum treatment, a process in which SF ₆ gas is filled into the inner container in a vacuum state, and a synthetic resin around the inner container filled with SF ₆ gas is A container-housed capacitor element is created through a molding process, and then a plurality of these container-housed capacitor elements are assembled into an outer container, and the inside of the outer container is vacuum-treated.
The manufacturing method is characterized by a step of enclosing SF ₆ gas.

Hereinafter, each process will be explained using FIGS. 1 to 4 of the drawings. In addition, FIG. 1 is a drawing showing an outline of a film winding device that winds up metallized films while stacking them in an SF ₆ gas atmosphere, and FIG. 2 is an enlarged cross-sectional view of the main parts of a container-housed capacitor element.
FIG. 3 is a diagram schematically showing a vacuum chamber device capable of vacuum processing, introduction of SF ₆ gas, and synthetic resin molding, and FIG. 4 is a cutaway sectional view of a high-pressure capacitor.

In the film winding device shown in FIG. 1, the film winding shaft is located at the bottom of a tank 1, and when SF ₆ gas is introduced into the tank 1, the SF ₆ gas 3 is replaced with air 2.
at the bottom of tank 1 to have a density about 5 times that of
A pool of SF ₆ gas 3 is created, and it is set to be located inside this pool.

When the metallized films 5 and 6 are wound up in the atmosphere of the SF ₆ gas 3 accumulated at the bottom of the tank 1, the SF ₆ gas 3 is trapped in the gap created between the wound metallized films 5 and 6. A void 7 of SF ₆ gas 3 is created between the metallized films of the wound element.

In addition, as for winding the metallized film in an SF ₆ gas atmosphere, for example, although not shown, immediately before winding the metallized films 5 and 6 to be wound,
Winding may be performed while introducing SF ₆ gas. In this case, the SF ₆ gas 3 is trapped in the gap between the metalized films 5 and 6 being wound up in the same manner as above, and the SF ₆ gas 3 is trapped between the metalized films of the wound element.
A void 7 of gas 3 will be created.

To continue manufacturing such an element, since SF ₆ gas is already contained in the tank 1, the bobbin 4 is set on the winding shaft, the metallized films 5 and 6 are set on this bobbin 4, etc. After performing various operations through the upper opening of the tank 1, the process proceeds to winding up the metal films 5 and 6. When the amount of SF ₆ gas in the tank 1 is exhausted and becomes low, it is replenished from the upper opening of the tank 1 as appropriate.

The voids 7 of the SF ₆ gas 3 generated between the wound metallized films are divided into two types: one in which it cannot easily escape and the other in which it easily flows out, depending on the position and shape of the void 7. The majority of the voids are in a condition that cannot be easily removed, and some of the voids located at the winding end surface are
It is thought that SF ₆ gas will be able to escape outside.

The element wound in this way is taken out into the atmosphere, and metal is thermally sprayed on both wound end faces of the element in the atmosphere. A connecting electrode 8a is formed on the metal thin film 5a of the other metallized film 6, a connecting electrode (this electrode is not shown in the drawing) is formed on the metal thin film 6a of the other metallized film 6, and a lead wire 9 is connected to the electrode 8a.
A is connected by soldering, and a lead wire 9b is connected to an electrode (not shown in the drawing) by soldering to obtain a capacitor element 10.

During work in such an atmosphere, voids 7 of the device that cannot easily escape to the outside remain trapped inside, and voids that can easily escape to the outside are SF. ₆ Gas will escape.

This capacitor element 10 is subsequently housed in the inner container 12 in the atmosphere. Note that capacitor element 1
This inner container in which 0 is housed has an inner diameter slightly larger than the outer diameter of the capacitor element 10, and has a terminal hole formed at the bottom through which one of the lead wires 9b of the capacitor element 10 is inserted and drawn out to the outside. The container body 12b has an inner circumferential surface that fits into the outer circumferential surface of the upper opening of the container body 12b, and has a terminal hole in the upper part through which the other lead wire 9a of the capacitor element 10 is inserted and drawn out to the outside. The air inside the inner container 12 can be evacuated between the fitting surface of the container body 12b of the inner container 12 and the lid 12a.
In addition, the inner container can be filled with SF ₆ gas, and when molding synthetic resin around the inner container 12, a gap 12c is formed that is large enough to prevent the mold resin from easily penetrating into the inner container 12. It has been done.

A glass cloth 11 is wrapped around an inner container 12 containing a capacitor element 10. The glass cloth 11 is designed to have a gap that does not affect the evacuation of the air in the inner container 12 and the filling of the SF ₆ gas 3.

The capacitor element 10 is housed in the inner container 12, the glass cloth 11 is wrapped around the inner container 12, this is set in the mold 14, and the vacuum chamber 1 is placed.
Put it in 5. When the valve 17 of the vacuum chamber 15 is opened, the other valves 16, 18, and 19 are closed, and the vacuum pump is operated to draw a vacuum, the air inside the inner container 12 flows from the gap 12c through the gap between the glass cloth 11 and into the vacuum chamber 15. It is possible to perform vacuum treatment by evacuating outside the chamber.

After vacuum treatment, valve 17 is closed and valve 18 is closed.
is opened and SF ₆ gas is introduced into the vacuum chamber 15 to fill the inner container 12 with SF ₆ gas 3.

When filling the inner container 12 with SF ₆ gas, the SF ₆ gas can be filled into the empty spaces where the SF ₆ gas has leaked out during the electrode spraying and lead wire connection.

Close the valve 18 and open the valve 19 to release the mold 1.
Put the synthetic resin liquid 20' into the chamber 4, surround the inner container 12 filled with SF ₆ gas 3 with the synthetic resin liquid 20', and then heat and harden while maintaining the positive pressure inside the vacuum chamber. By reacting, the molding process of the synthetic resin 20 is completed, so that the container-housed capacitor element 13 can be obtained by taking it out.

In addition, in the process of molding the synthetic resin 20, the synthetic resin liquid 20' when surrounding the inner container 12 with the synthetic resin liquid 20' is
Due to the size of the gap 12c between the container body 12b and the lid 12a, the air inside can be exhausted by vacuuming, and SF ₆ gas can be filled into the inner container 12 in a vacuum state, but the synthetic resin liquid 20' can be easily filled. Since it is formed to a size that cannot be penetrated, it is impossible to penetrate into the interior of the inner container 12 through such a gap 12c. That is, since the synthetic resin liquid 20' cannot enter the interior of the inner container 12, the inner container 1
This means that no external force is applied to the SF ₆ gas filled in the inner container 12 to cause it to be discharged to the outside of the inner container 12.
Therefore, the SF ₆ gas does not become bubbles in the synthetic resin liquid 20' and is discharged to the outside, and the inner container 12 of the container-housed capacitor element 13 can be filled with a predetermined amount of SF ₆ gas. It will be possible.

Next, a plurality of container-housed capacitor elements 13 filled with a predetermined amount of SF ₆ gas in this manner are assembled, and this assembly is housed in the outer container 21.

The outer container 21 has a container body 21a and a lid 21.
The lid body 21b is fixed to the container body 21a in a sealed manner by bolting or the like via a sealing material. Further, the lid body 21b is integrally provided with bushings 22, 22 for connecting the lead wires of the container-housed capacitor element 13, and is provided with an injection port 23 for filling the SF ₆ gas 3.

Container-housed capacitor element 13 in outer container 21
A lid body 21b is attached to the container body 21a.
After fixing in a sealed state, the inside of the outer container 21 is evacuated through the injection port 23, SF ₆ gas is filled into the vacuumed outer container 21, and the injection port 23 is sealed. It is possible to obtain a high-voltage capacitor manufactured using the same method.

(c) Effects of the invention (1) By winding up a metallized film in an SF ₆ gas atmosphere, SF ₆ gas is trapped between the rolled up metallized films, and the SF ₆ gas is trapped. Most of the voids 7 are retained inside so that they cannot easily escape to the outside, and the voids of the SF ₆ gas that has flowed out can be filled with SF ₆ gas in the subsequent process. A container-housed capacitor element with a high discharge starting voltage can be obtained.

(2) The SF ₆ gas that has accumulated inside the device cannot easily escape to the outside, and the voids of the SF ₆ gas that have leaked out can be filled with SF ₆ gas, allowing the device to be exposed to the atmosphere. You can take it out and spray metal electrodes on both ends of the winding, and connect the lead wire.
Electrode formation and lead wire connection work become easier.

(3) It is possible to test the operation of the container-housed capacitor elements at the stage of assembling them into an assembly, and it is possible to determine whether they are good or bad, which has the effect of reducing the number of ineffective man-hours in subsequent processes.

(4) In this invention, the airtightness of the high-voltage capacitor manufactured by the manufacturing method is double maintained by the inner container and the outer container. For example, even if an airtight leak occurs in the outer container, the airtightness of each capacitor element will be maintained by the inner container, and as a result, the insulation properties of the capacitor elements will not deteriorate and even if moisture etc. enters the outer container, the airtightness of each capacitor element will be maintained by the inner container. The capacitor element is protected. Furthermore, even if an airtight leak of SF ₆ gas occurs from the inner container, the pressure of the SF ₆ gas filled in the inner container will not drop due to the SF ₆ gas filled in the outer container, and this will prevent corona discharge of the capacitor element. The starting voltage does not drop, and the outer container prevents moisture from entering from the outside, thereby protecting the capacitor element.

Therefore, the present invention has the effect of further improving the reliability and extremely long life of the high voltage capacitor manufactured by the manufacturing method.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an outline of a film winding device, Fig. 2 is an enlarged sectional view of main parts of a container-housed capacitor element, Fig. 3 is an explanatory diagram showing an outline of a vacuum chamber device, and Fig. 4 is a high pressure Cutaway sectional view of capacitor, No. 5
The figure is a cutaway sectional view of a high-voltage capacitor illustrating a conventional example. DESCRIPTION OF SYMBOLS 1... Top open tank, 2... Air, 3... SF ₆ gas, 4... Bobbin, 5, 6... Each metallized film, 5a, 6a... Each metal thin film, 7... SF ₆ gas void, 8a... Electrode, 9a , 9b...Respectively lead wire, 10...Capacitor element, 11...Glass cloth, 12...Inner container, 12a...Lid body, 12
b... Container body, 13... Container housed capacitor element, 14... Mold, 15... Vacuum chamber, 16, 17, 1
8, 19...Valve respectively, 20'...Synthetic resin liquid,
20...Synthetic resin, 21...Outer container, 22...Butting, 23...Inlet.

Claims (1)

[Claims] 1 First, a metallized film with a metal thin film formed on a plastic film is heated with sulfur hexafluoride gas (hereinafter referred to as
The process of winding the wound element in an atmosphere (simply referred to as SF ₆ gas), the process of forming electrodes on both end faces of the element and connecting the lead wires to the wound element in the atmosphere, and the process of forming electrodes and connecting the lead wires to the capacitor element. The process of placing the liquid in a container and vacuum-processing it.
A container-housed capacitor element is created through the steps of filling SF ₆ gas and molding the inner container filled with SF ₆ gas with synthetic resin, and then assembling multiple container-housed capacitor elements. A method for manufacturing a high-voltage capacitor, which includes the following steps: placing the capacitor in an outer container, vacuum-treating the inside of the outer container, and sealing SF ₆ gas in the outer container in a vacuum state.