JPH07240336A - High-voltage power capacitor - Google Patents

Abstract

PURPOSE:To improve the insulation restoring property of a film at a defective part when the defective part occurs due to a dielectric breakdown by forming a plurality of vapor-deposited metallic electrodes by providing a plurality of insulating belts and serial and parallel circuits of small-capacitance capacitors. CONSTITUTION:A plurality of serial capacitors are constituted by forming a plurality of belt-like vapor-deposited metallic electrodes 1 and 1' by providing a plurality of insulating belts 2 and 2' in the length directions of metallized polyolefin films A and B. Then serial and parallel circuits of small-capacitance capacitors C1 and C2 are formed by forming sprayed electrodes on both end faces of a wound body of a small capacitor net constituting a plurality of parallel circuits by forming a plurality of island-like vapor-deposited metallic electrodes by providing a plurality of insulators 3 and 3' in the direction perpendicular to the length directions of the films A and B. After forming the circuits, the circuits are impregnated or filled up with an independent liquid insulator, gaseous insulator, or solid insulator. Therefore, even when a dielectric breakdown occurs at a weak point part of the metallized films, the insulation of the part is restored, because the vapor-deposited metallic electrode at the part is scattered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to high-voltage and extra-high-voltage power,
The present invention relates to a high-voltage capacitor for power such as surge absorption, ground compensation, and filter.

[0002]

2. Description of the Related Art A conventional high-voltage capacitor for electric power uses paper or a plastic film or a combination of paper and a plastic film as a dielectric, and uses aluminum foil as an electrode foil. Are alternately superposed and wound to form a capacitor element, and one or more capacitor elements are assembled,
Depending on the parallel connection or the voltage, series connection or series-parallel connection was performed to form the one having the necessary withstand voltage and capacitance. Further, as another technique, recently, a metallized plastic film or the like in which a metal is vapor-deposited is used instead of an aluminum foil electrode to form a dielectric.

[0003]

The dielectric of the capacitor is thin and has a large area of several μm to several tens of μm.
Therefore, in the withstand voltage of the dielectric material, defects are likely to occur, and although these defective parts are very small in area, it was necessary to design the capacitors in consideration of the defective parts. In the conventional design, a method of covering a minute defect portion of one dielectric with another dielectric by superposing several thin dielectrics has been mainly adopted. The better the effect, the better the effect. However, when the number of superposed dielectrics is increased, the thickness between the electrodes becomes thicker, which has a drawback of causing corona discharge from the end faces of the electrodes and shortening the life of the capacitor. As another countermeasure against defects, there is also a method of recovering the insulation by evaporating and scattering the electrode metal around the dielectric defect part by the vapor-deposited metal electrode by the discharge current at the time of dielectric breakdown. Since it is difficult to shut off, it has not been put to practical use.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is to improve the vapor-deposited metal electrode so as to dramatically improve the insulation recovery property at the time of dielectric breakdown in the defective portion of the film. The electrode is divided into a plurality of islands, the vapor-deposited metal electrodes divided into islands are connected in series and in parallel, and the edge-deposited metal electrode is connected to the metallikon electrode, which is an external extraction electrode, As a whole, a mesh-like small capacitor network as shown in FIG. 2 is formed, and the discharge energy for the discharge at the defective portion of the film is made minute to reduce the destruction portion at the time of discharge, and if some of the electrodes Even if a short circuit occurs, the capacity of the series capacitor is kept small enough to suppress the partial short-circuit current and make the current recoverable during normal capacitor operation. It is limited.

That is, (1) a metallized polyolefin film in which a vapor-deposited metal electrode is formed by leaving an edge insulating band at one end of one side of a polyolefin film, or a polyolefin film is inserted between the metallized polyolefin films and wound. In the high-voltage capacitor for electric power consisting of the above, a plurality of insulating bands are provided in the length direction of the metallized polyolefin film to form a plurality of strip-shaped vapor-deposited metal electrodes to form a plurality of capacitors in series, and Of a winding body of a small capacitor network in which a plurality of island-shaped vapor-deposited metal electrodes are formed by providing a plurality of insulating bands in a direction perpendicular to the longitudinal direction of the modified polyolefin film to form a plurality of parallel circuits. Metallicon electrodes are formed on both end faces to form a series-parallel circuit of small-capacity capacitors. A high-voltage capacitor for electric power, characterized in that it is impregnated and filled with one of a body insulator and a solid insulator. (2) The number of insulating bands provided in the direction perpendicular to the longitudinal direction of the metal or the polyolefin film is different from that of other evaporated metal electrodes only in the edge evaporated metal electrodes. It is the high-voltage capacitor for electric power of the above (1). (3) The stored energy of the small capacitor is 0.1 J or less at the peak value of the rated voltage, and the rated effective voltage of the small capacitor is 600 VAC or less. It is a capacitor.

[0006]

The thinner metallized film forming the capacitor element shown in FIG. 1 (A) or (B), the better the insulation recovery property, and usually about 4 to 10 .mu.m is suitable from the viewpoint of cost and production technology. Is. When an AC voltage of 50 V / μm (effective value) is applied to this, the voltage becomes 200 to 500 VAC, and the peak voltage is 283 to 707 V. Continuous application of such a voltage to the metallized film may cause dielectric breakdown. If there is no voltage drop at the time of dielectric breakdown, the evaporated metal around the dielectric breakdown will evaporate and scatter, but if the potential gradient is high, the insulation will not be recovered or the location of the breakdown will be significantly increased and the insulation characteristics will be significantly reduced. Then
It fails because it does not function as a capacitor. The capacitor element of the present invention has a structure in which metallized films A and B provided with insulating bands 2, 2 ′ and 3, 3 ′ are superposed and wound as shown in FIG. 1 (A) or (B). , For example, the small capacitor C1 is defective and causes dielectric breakdown,
Even if all the charged charges of the small capacitors C1 and C2 are discharged,
Small capacitor C1 + C2 charge energy 0.1J
If it is made as small as possible, the diameter of the evaporation and scattering portion of the vapor-deposited metal electrode can be suppressed to 2 mmφ or less, and the damage does not spread to the portion exceeding it.

In the example shown in FIG. 1 (A) or (B) and its equivalent circuit, which is shown in FIG. 2, since the number of series of small capacitors in the capacitor element is 9, there is no difference between the small capacitors having a dielectric breakdown. The number of small capacitors connected in series is 8, and when the voltage between the edge-deposited metal electrodes 1 and 1'is compared with the 8 small capacitors connected in series,
Its overvoltage is 1.125 times, which is well within the safe range. In addition, even if the small capacitor that caused the dielectric breakdown is discharged to zero voltage during the dielectric breakdown, the AC voltage is applied by adding a DC bias to the AC voltage that is continuously applied, and the peak value of that voltage reaches a maximum of 2 times. However, it has secured sufficient safety against this voltage. Explaining the above concretely with numerical examples,
The material of the metallized films A and B of FIG. 1 (A) or (B) is polypropylene, and the thickness is 8 μm and the width is 394 m.
m, aluminum is vacuum-deposited on the metallized films A and B, and the insulating strips 2 and 2'having a width of 6 mm in the longitudinal direction of the set.
When 9 pieces of small capacitors are provided in series, the effective electrode width of each small capacitor is 36 mm. Further, when the insulating strips 3 and 3'having a width of 6 mm are provided at a pitch of 100 mm in the direction perpendicular to the longitudinal direction of the same metallized films A and B, the facing area of this one block of the small capacitor network is 36 × 94 = It is 3.384 × 10 ³ mm ² , and the capacity is 0.0172 μF. When a voltage of 376 VAC (effective value) is applied to this, the peak value voltage is 367 ×
√2 = 519V. The stored energy Jc per small capacitor at this time is expressed by the equation 1.

[0008]

[Equation 1]

Even if all of them are discharged, only local destruction is caused, and not destruction of the entire capacitor. Also, the part where a part of the capacitor became conductive due to dielectric breakdown,
A current of 2.38 mA flows under the rated use condition. With a current of this level, the vapor-deposited metal electrode melts and scatters, and the insulation recovers itself.

[0010]

【Example】

Example 1 The metallized films A and B of the present invention (8 μm thick, 394
(mm width) and the flattened and flattened metallikon electrodes at both ends thereof to obtain three phases, 60 Hz, 660
A specific example of a 0 VAC, 100 kVA high-voltage power capacitor will be described. The rating of one capacitor element 5 was 3300 VAC, 2.03 μF, and 8.34 kVA, and 12 capacitor elements 5 were assembled to form a capacitor unit. One capacitor element 5 is composed of about 10,000 small capacitor networks, and 12 of these are assembled to make a total of about 1
A capacitor unit 6 composed of a network of 20,000 small capacitors is formed, housed in an iron plate container 9, vacuum dried, and filled with sulfur hexafluoride (SF ₆ ) which is a gas insulator. The high voltage capacitor for electric power of Example 1 was manufactured. The capacitor has a stable self-healing property during use,
In the continuous durability test, the test voltage was 8840 VAC (rated voltage × 1.34 times), and the rate of change in capacity after a test time of 1200 h was −0.98% with respect to the initial value, which was a very good electric characteristic.

Example 2 The metallized films A and B of the present invention (8 μm thick, 39
A high-voltage capacitor for electric power having the same rating as that of Example 1 but having a different filler was manufactured by using zinc as a vapor deposition electrode metal having a width of 4 mm). The filler is impregnated and filled with a mixture of vegetable oil and aromatic hydrocarbon of a mixed liquid insulation. The capacitor obtained a stable self-healing property during use, the test voltage was 8840 VAC (rated voltage × 1.34 times) in the continuous durability test, and the rate of change in capacity after a test time of 3000 h was −0. 86%, which was an extremely good electric characteristic. In Examples 1 and 2 described above, the material of the metallized film was polypropylene film, but other polyolefin film such as polyethylene may be used, and the polyolefin film may be interposed between the metallized films. Also obtained similar good results. In addition, regarding the insulator to be impregnated and filled, other gas insulators other than the above, solid insulators such as epoxy resin, aromatic hydrocarbon insulating oils such as mineral oil, alkylbenzene, alkylnaphthalene, rapeseed oil, castor oil, large Good electrical characteristics of the capacitor could be obtained by using vegetable oil such as soybean oil, ester-based insulating oil such as phthalic acid ester and sebacic acid ester, insulating oil such as silicone oil, and mixed liquid insulating materials of these.

[0012]

Since the high-voltage capacitor for electric power of the present invention is constructed as described above, even if the dielectric breakdown occurs at the weak point of the metallized film during use, the vapor-deposited metal electrode in that part scatters and insulates. Recovering and significantly improving reliability,
It has high electric field strength, has effects such as miniaturization and can be manufactured at low cost, and has great industrial and practical value.

[Brief description of drawings]

FIG. 1A and FIG. 1B are plan views of a main part of the form and arrangement of vapor-deposited metal electrodes of a pair of metallized films that constitute a capacitor element according to the present invention.

FIG. 2 is an internal wiring diagram of a capacitor element according to the present invention.

FIG. 3 is a perspective view of a capacitor element.

FIG. 4 is a perspective view of a capacitor unit.

FIG. 5 is a perspective view of a finished product.

[Explanation of symbols]

A, B: Metallized film 1, 1 ': Metallized film A, B edge-deposited metal electrode 2, 2': Insulation band in the longitudinal direction of metallized film A, B 3, 3 ': Metallized film Insulation band perpendicular to the longitudinal direction of A and B 4: Metallikon metal 5: Capacitor element 6: Capacitor unit 7: Interphase insulating plate 8: Tightening plate 9: Iron plate container 10: Lead-out terminal 11: Power high-voltage capacitor C1, C2, C3 ...: Small capacitors

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hirokazu Sakaguchi Oike-dori, Nakagyo-ku, Kyoto Prefecture 1st floor, Karasuma Higashiiri 1st line, 4th Uehara Bldg., 191, Nakaboricho Nichicon Corporation (72) Inventor Shusaku Tsujio 4th Uehara Building, Nichicon Co., Ltd., 191, Nakabori-cho, Oike Dori, Karasuma Higashiiri, Nakagyo-ku, Kyoto City, Kyoto Prefecture

Claims (3)

[Claims] 1. A metallized polyolefin film in which a vapor-deposited metal electrode is formed by leaving an edge insulating band at one end of one side of a polyolefin film, or a polyolefin film is interposed and wound between the metallized polyolefin films. In a high-voltage capacitor for electric power, a plurality of insulating strips are provided in a longitudinal direction of the metallized polyolefin film to form a plurality of strip-shaped vapor-deposited metal electrodes to form a plurality of capacitors in series, and the metallized polyolefin film is formed. Both end surfaces of a winding body of a small capacitor network in which a plurality of insulating bands are provided at right angles to the longitudinal direction of the plurality of islands to form a plurality of island-shaped vapor-deposited metal electrodes to form a plurality of parallel circuits. A metallikon electrode is formed on the to form a series-parallel circuit of a small capacity capacitor, and a single liquid insulator, a mixed liquid insulator, a gas insulator, and a solid insulator are formed. Power high-voltage capacitor, characterized in that the impregnation and filling any one of the insulator. 2. The number of a plurality of insulating bands provided in a direction perpendicular to the longitudinal direction of the metallized polyolefin film is different from that of other evaporated metal electrodes only in the edge-deposited metal electrode. The high-voltage capacitor for electric power according to claim 1. 3. The energy stored in the small capacitor is
The high voltage capacitor for electric power according to claim 1, wherein the peak value of the rated voltage is 0.1 J or less, and the rated effective voltage of the small capacitor is 600 VAC or less.