JPH03280410A - High voltage power capacitor - Google Patents

Abstract

PURPOSE:To improve the insulation recovery characteristics when the defective part of a film is dielectrically broken down by a method wherein the vapor-deposited metal electrode only at the edge part of a vapor-deposited metal small capacitor network, consisting of a plurality of parallel circuits which are formed by providing a plurality of insularly vapor-deposited metal electrodes, is formed into one or a plurality of continuous conductors. CONSTITUTION:A capacitor element is formed by lap-winding two sheets of metallized polyolephine films having vapor-deposited metal electrodes 1 and 1' formed on one side. A plurality of series capacitors are formed between the edge part vapor-deposited metal electrodes 1 and 1' by providing dielectric bands 2 and 2 in longitudinal direction of the metallized films A and B, and the capacitance of a capacitor element is made equal to that obtained by parallel-connecting a plurality of divided small capacitors by providing dielectric bands 3 and 3' in the direction at right angle to the longitudinal direction. The internal connection is formed in such a manner that a number of small capacitor groups are reticularly arranged in series connection and parallel connection between the edge part vapor-deposited metal electrodes 1 and 1'. One of a mixed solution insulator, a gaseous insulator or a solid insulator is impregnated and filled therein.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a high-voltage capacitor for power use such as high-voltage, extra-high-voltage power, surge absorption, ground compensation, and filter use.

Conventional technology Conventional power high voltage capacitors use paper or plastic film, or a combination of paper and plastic film, as the dielectric, and use aluminum foil as the electrode foil, with the dielectric and electrode foil alternated. The capacitor elements are stacked and wound to form a capacitor element, and one or more capacitor elements are connected in parallel or in series or series-parallel depending on the voltage to obtain the required withstand voltage and static It consisted of capacitance. In addition, metallized paper on which metal is vapor-deposited in place of the aluminum foil electrode or the dielectric material of the metallized plastic fill capacitor are thin with a thickness of several μm to several tens of μm and have a large area. Therefore, defects are likely to occur due to the dielectric's withstand voltage. Although this defective portion is minute in area, it was necessary to take the defective portion into consideration when designing the capacitor.

In conventional designs, a method has been adopted in which several sheets of thin dielectric material are overlapped to cover minute defects in one dielectric material with another dielectric material. This method became more effective as the number of stacked thin dielectrics increased. However, increasing the number of stacked dielectrics increases the thickness between the electrodes, which has the disadvantage of generating corona from the end faces of the electrodes, shortening the life of the capacitor. In addition, as another defect countermeasure, the electrode metal around the dielectric defect area using a vapor-deposited metal electrode is
There is a method to recover the insulation by evaporating and scattering it using the discharge current at the time of dielectric breakdown, but this method has not been put to practical use because high-voltage capacitors do not have the ability to cut off the current at the time of dielectric breakdown.

Means to Solve the Problem The principle is that a vapor deposited metal electrode is divided into multiple islands, and the island-shaped divided vapor deposited metal electrodes are connected in series and parallel to each other to prevent discharge from occurring in defective areas of the film. In addition to reducing the discharge energy and reducing the damage caused by the impact force during discharge, even if some parts become short-terminated and continuous current flows, insulation recovery is possible because the capacitance of the series capacitor part is small. current.

FIG. 1 shows a plan view of essential parts of the form and arrangement of the vapor-deposited metal electrodes of a pair of metallized films constituting a capacitor element having this function. Figure 1 shows evaporated metal mold 8i on one side! (
A capacitor element is constructed by overlapping and winding two metallized films A and B with a diagonal (shaded area in the figure), and the two metallized films A and B have the same shape and are
The arrangement is rotated by 0°. 1.1″ is metallized film A
, B is a vapor-deposited metal electrode on the edge portions of the metallized films A and B which are adhered to the metallicon metal sprayed on the end face of a capacitor element formed by overlapping and winding the metallized films A and B. 2.2 is a metal-deposited metal type i1.1. ° form multiple series capacitors. 3.3° is an insulating band provided perpendicular to the longitudinal direction of metallized films A and B, and by providing insulating band 2.2' and insulating band 3.3'', one capacitor element is The capacitor is formed by connecting a large number of small capacitors divided in parallel.Edge vapor-deposited metal electrodes 1, 1
In order to ensure the adhesion to the metallic metal, a continuous electrode is used without providing an insulating band. FIG. 3 shows the shape of a capacitor element 5 in which the metallized films A and B formed as described above are superimposed and wound, then pressed flat and sprayed with metallicon metal 4 on both end faces.

FIG. 2 shows the internal wiring of the capacitor element 5 shown in FIG. 3. FIG. 2 shows a large number of small capacitor groups arranged in series and in parallel in a mesh pattern between the edge evaporated metal molds 8iil, 1'.

The capacitance of one of the small capacitor groups is determined by varying the spacing of the longitudinal insulating strips 2,2° of the metallized films A, B and 3.3' of the insulating strips perpendicular to the winding direction. In the part shown, the capacitance of small capacitors C1 and C2 differs depending on the overlapping state of the insulating bands 3 and 3 degrees of the metallized film A=H, but by keeping the interval of 3 and 3 degrees of the insulating bands constant, the small capacitors C1 and C2 can be The capacitances of c and +c2 are constant. The small capacitor C2+03 is also constant.

Function: The thinner the metallized film constituting the capacitor element shown in FIG. 1, the better the insulation recovery characteristics.

In view of current production technology and cost, the appropriate thickness of the metallized film is about 4 to 10 μm, and 50 V
/μm (effective value), the voltage will be 200 to 500 VAC, and the peak voltage will be 283
~707v. Continuous application of such voltages to the metallized film may cause dielectric breakdown. If there is no voltage drop at the dielectric breakdown area, the vapor deposited metal around the dielectric breakdown area will evaporate and scatter, but due to the high potential gradient, insulation recovery will not occur or the breakdown area will become significantly large, causing the performance of the present invention. As shown in Figure 1, the capacitor element has a structure in which metallized films A and B provided with insulating bands 2.2' and 3.3' are overlapped and wound.For example, if a small capacitor C1 has a defect, Even if dielectric breakdown occurs and all the charges in the small capacitors C1 and 02 are discharged, if the charging energy of the small capacitors C1+02 is kept to 0.1 J or less, the diameter of the evaporation and scattering part of the vapor-deposited metal electrode can be suppressed to 2 mm or less. , the destruction will not spread to areas beyond that point.

In the example shown in Figure 1, the number of small capacitors connected in series inside the capacitor element is nine, so the number of small capacitors connected in series with the small capacitor that caused dielectric breakdown is eight, and The voltage across the 8 small capacitors connected in series between the metal electrodes 1 and 1° is 1.125 times higher, but this voltage is well within a safe range.・Also, even if a small capacitor that has dielectric breakdown discharges to zero voltage at the time of dielectric breakdown, an AC voltage with a DC bias added to the subsequently applied AC voltage will be applied, and the time constant will be approximately one day. There is no problem because it is attenuated.

EXAMPLE Hereinafter, the present invention will be explained with reference to FIGS. 1 to 5. 1st
The film material of metallized films A and H shown in the figure is polypropylene, and electrode parts are formed by vacuum-depositing zinc or aluminum on a polypropylene film with a thickness of 8 μm and a width of 394 mm. When nine small capacitors are connected in series by providing insulating bands 2.2° with a width of 6 mm in the longitudinal direction of the films A and B, the effective width of one small capacitor is 36 mm, and the metallized films A and B An insulating band 3.3'' with a width of 6 mm is provided in the direction perpendicular to the longitudinal direction of the insulating band 3 and 3 or the insulating band 3
If the interval between ° and 3° is 10On+n, the opposing area of the small capacitor is 36X 94 = 3.384X 103m
m2, the capacitance is 0.0172 μF. 367 to this
When applying an effective value voltage of v, its peak value is 367X
J2 = 519v.

When an effective value voltage of 367V is applied to this, the wave height becomes that value, and even if it is completely discharged, it will only cause local destruction and will not lead to destruction of the entire capacitor. Further, where a part of the capacitor becomes conductive due to dielectric breakdown, a current of 2.38 mA in the rated usage state flows, so that the vapor-deposited metal electrode melts and scatters, recovering the insulation.

Next, a specific example of a three-phase, 60 Hz, 6600 V, 100 kVA power high voltage capacitor using the metallized films A and B according to the present invention will be described.

The rating of one capacitor element 5 is 3300VAC12
, 03 μF, 8.34 kVA, and is composed of 12 cono-condenser elements 5. The capacitor element 5 is made of a polypropylene film with a thickness of 8 μm and a width of 394 μm, and two metalized films with vapor-deposited metal electrodes placed on top of each other to form nine series small capacitors.
FIG. 4 shows a case where a 100 kVA capacitor unit 6 is constructed by winding and pressing flat, spraying metallicon metal 4 on both end faces, and assembling 12 constituent elements 5 at 7 as shown in FIG. 3. , 7 is an interphase insulating plate, and 8 is a tightening plate. This capacitor unit 6 is composed of a circuit network including approximately 120,000 small capacitors. FIG. 5 shows the capacitor unit 6 connected to a lead-out terminal 10.
1 is an external view of a high-voltage power capacitor 11 housed in an iron plate container 9 equipped with the following. The processing of the power high-voltage capacitor 11 is carried out by storing the capacitor unit 6 in a container 9 and drying it in a predetermined vacuum, and then using aromatic hydrocarbon-based insulating oil such as mineral oil, alkylbenzene, or alkylnaphthalene, rapeseed oil, or
Vegetable oils such as cottonseed oil, castor oil, and soybean oil; ester-based insulating oils such as phthalate esters and separatate esters; liquid insulators such as silicone oil; and mixtures of these liquid insulators (e.g., vegetable oils and aromatic hydrocarbon insulating oils) ) or science fiction.

Impregnated and filled with gas insulators such as gas or solid insulators such as epoxy resin.

In the above example, similar results were obtained even when a metallized polyolefin film in which a vapor-deposited gold electrode was provided on a polypropylene film was used. Similar results were also obtained when a polyolefin film was interposed between metallized polyolefin films.

Effects of the Invention Since the high-voltage capacitor for power use of the present invention is constructed as described above, even if insulation breaks down at a weak point in the metallized film during use, the vapor-deposited metal electrode at that portion will scatter and the insulation will be restored. However, the reliability is significantly improved and the electric field strength is high.
It has the advantage of being smaller and can be produced at a lower cost, and is of great value in industrial and practical applications.

[Brief explanation of drawings]

The figure shows a high-voltage capacitor for power use according to the present invention. Figure 1 is a plan view of essential parts of the form and arrangement of the vapor-deposited metal electrodes of a pair of metallized films constituting the capacitor element, and Figure 2 is an internal wiring diagram of the capacitor element. FIG. 3 is a perspective view of a capacitor element, FIG. 4 is a perspective view of a capacitor unit, and FIG. 5 is a perspective view of a completed product. A, B: Metallized film 1.1': Vapor-deposited metal electrode at the edge of metalized film A, B 2.2": Insulating band in the longitudinal direction of metalized film A, B 3.3": Metallized film Insulating strip 4 perpendicular to the longitudinal direction of A-B: Metallic silicone metal 5: Capacitor element 6: Capacitor unit 7 Two-phase insulating plate 8: Tightening plate 9: Iron plate container 10: Output terminal 11: High-voltage capacitor for electric power

Claims (2)

[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 the polyolefin film, or a high voltage for electric power produced by interposing a polyolefin film between the metallized polyolefin films and winding the film. In the capacitor, a plurality of insulating bands are provided in the longitudinal direction of the metallized polyolefin film to form a plurality of band-shaped vapor-deposited metal electrodes to form a plurality of capacitors in series, and a plurality of insulating bands are provided in the longitudinal direction of the metallized polyolefin film. Excluding the edge vapor-deposited metal electrodes in the direction perpendicular to the edge, multiple insulating bands are provided to form multiple island-shaped vapor-deposited metal electrodes to form multiple parallel circuits to form a small capacitor network. A high-voltage capacitor for power use characterized by being impregnated and filled with any one of a single liquid insulator, a mixed liquid insulator, a gas insulator, and a solid insulator. (2) The high voltage for electric power according to claim 1, wherein the stored energy of the small capacitor is 0.1 J or less at a peak value of the rated voltage, and the rated effective voltage of the small capacitor is 600 VAC or less. capacitor.