JPS607003A - Oil-filled capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Industrial applications The present invention is applicable to electrical equipment including electric power.

This relates to oil-immersed capacitors used for communications, etc.

Conventional structure and problems Conventional oil-filled capacitors use ester oils such as 7-talic acid esters and phosphoric acid esters, hydrocarbon-based insulating oils such as alkylbenzene (AB) and diallylalkane (DAA), etc. as insulating oils. Used alone or in combination. In practice, stabilizers such as epoxy stabilizers, phenol stabilizers, and bosphite stabilizers are added to the insulating oil in required amounts. These additives cause a chain decomposition reaction in which when an oil-immersed capacitor is used for a long period of time, the insulating oil deteriorates due to thermal and electrical energy and decomposition products increase, which in turn accelerates the decomposition reaction. It becomes impossible to maintain the initial electrical characteristics over a long period of time,
It was added to stop such chain decomposition reactions. There were also halogenated synthetic insulating oils with special silane compounds added for the same purpose, but in any case,
Conventional insulating oils maintain their initial electrical properties over long periods of time by adding stabilizers that chemically react with residual impurities and decomposition products in the insulating oil to stop chain decomposition reactions.

On the other hand, one of the performance requirements for oil-filled capacitors is whether they are nonflammable or flame retardant. One of the factors that determines this nonflammability or flame retardancy is whether the insulating oil impregnated into an oil-filled capacitor is nonflammable or flame retardant. Oil-filled capacitors include those made by mixing hydrocarbon insulating oil with phosphoric acid ester, and those impregnated with a liquid such as an organosilicon compound (for example, dimethylpolysiloxane, methylphenylpolysiloxane, etc.).

Insulating oil, which is a mixture of hydrocarbon-based insulating oil and phosphate ester, has excellent properties such as high dielectric constant and resistance to partial discharge, but on the other hand, compared to organosilicon compound liquids, the film swells more and is particularly susceptible to metallization. When insulating oil is impregnated between the film layers of a capacitor using film, the adhesion strength of vapor-deposited electrodes, etc. becomes extremely weak (especially when polypropylene film is used), which has the disadvantage of making it impractical. .

A problem that these conventional flammable 2, flame retardant or non-flammable capacitors have in common is that they have the characteristic that the dielectric loss factor (tan δ) increases rapidly when the temperature and potential gradient are increased. Figure 1 shows the tan δ-voltage characteristics of conventional oil-immersed capacitors at 100°C. ) 60% (volume ratio) and triisopropylphenylphosphor) (TIP) 4'O% (volume ratio) mixed oil with 1% epoxy stabilizer added to a flame-retardant insulating oil B1 dimethyl capacitor impregnated These are the characteristics of capacitor C impregnated with polysiloxane (DMS). The capacitor configuration in Figure 1 is an oil-immersed capacitor consisting of two sheets of electrode paper with metal vapor-deposited on both sides of the paper and two sheets of polypropylene dielectric film.The solid line indicates the case where the vapor-deposited metal is zinc, and the dotted line indicates the case where the vapor-deposited metal is aluminum. It is. The measured voltage was an AC voltage of 60 Hz, and the horizontal axis in FIG. 1 represents the potential gradient obtained by dividing the applied voltage by the film thickness. According to this, the higher the potential gradient, the higher the tan δ, and the case of zinc electrode paper was particularly worst. Although tan δ is lower in the case of aluminum electrode paper than in the case of zinc electrode paper, it still shows a remarkable tendency to increase in the high potential gradient region. In addition, the tan δ of flame retardant TIP and DAE mixed oil and DMS
Although DOP is extremely large and has the feature of flame retardancy, its dielectric properties are worse than that of flammable DOP. DA for TIP
As the volume ratio of E decreases, the flame retardance increases, but the dielectric properties worsen, and partial discharge does not occur (the capacitor suddenly discharges after a certain period of time without a sudden increase in tan δ). It was not possible to reduce the volume ratio of DAE that much due to unexplained phenomena such as destruction.This also increased the swelling of the plastic film, which extremely weakened the adhesion strength between the vapor-deposited electrode and the plastic film, which made it difficult to put it into practical use. It was making it difficult.

Purpose of the Invention The present invention provides an oil-immersed capacitor that is flame retardant, has very little melting or swelling of plastic, and has a high potential gradient that conventional capacitors of this type could not have.
It is an object of the present invention to provide a new oil-immersed capacitor having a characteristic that an δ does not become large.

Structure of the Invention As a further structure, the present invention is formed by impregnating a capacitor element consisting of at least two electrodes and a dielectric interposed between the electrodes with an insulating oil consisting of a main insulating oil and an additive added thereto. The main insulating oil is an organosilicon compound, and the additive is a silane coupling agent.

Description of Examples The organosilicon compounds used in the present invention include general organosilicon compounds such as dimethylpolysiloxane and methylphenylpolysiloxane, as well as the following general formula (wherein R is phenyl or
-butylphenyl, R' is methyl or phenyl, and It is an organosilicon compound made of tetraalkylsilane.

The additive has the following general formula (wherein R1 is hydrogen or 01-C4 alkyl,
R2 is 01-C8 alkylene or 06-018 substituted or unsubstituted arylene; R5 is C+-C8 alkyl/l/, C1-C8 alkoxy, 06-C+a substitution; C6-C+a substituted or unsubstituted aryloxy, R4 and R5 are C1-C8 alkoxy-C1-C
8 acyloxy or 06-Cue substituted or unsubstituted aryloxy) or the following general formula (wherein R1 is 01-C8 alkylene or 06-C+
a-substituted or unsubstituted a+J-lene, R2 is C1
~C8 alkyl, 01~C8 alkoxy, 06~(+a
Substituted or unsubstituted aryl, 01-C8 acyloxy or C6-01a substituted or unsubstituted aryloxy, R3 and R4 are C1-C8 alkoxy, C
1-C8 acyloxy or 06-.018 substituted or unsubstituted aryloxy) or the following general formula (wherein R1 is hydrogen or C1-C4 aminoalkyl and R2 is 01-C8 alkylene or 06-C+a
Substituted or unsubstituted arylene, R3 is 01-C
8 alkyl, C1-C8 alkoxy, C6-018 substituted or unsubstituted aryl, 01-C8 acyloxy or C6-e1a substituted or unsubstituted aryloxy, R4 and R5 are C1-C8 alkoxy-01-C
8 acyloxy or 06 to 018 substituted or unsubstituted aryloxy) or the following general formula % (wherein R1 to 01 to CB alkylene or 06 to (+
a-substituted or unsubstituted arylene, and R2 is C1-
C8 alkyl, 01-C8 alkoxy, C6-C+a substituted or unsubstituted aryl, 01-CB acyloxy or 06-CI8 substituted or unsubstituted aryloxy, and R3 and R4 are C1-C8 alkoxy, 01-
C8 acyloxy or 06-e1a substituted or unsubstituted aryloxy) or alternatively the following general formula % (wherein R1 is C1-C8 alkylene or 06-Cj
+s substituted or unsubstituted arylene, R2 is C1
~C8 alkyl, 01~C8 alkoxy, 06~C+s
Substituted or unsubstituted aryl, 01-CB acyloxy or 06-G+8 substituted or unsubstituted aryloxy, R5 and R4 are C1-C8 alkoxy, 0
1-C8 acyloxy or 06-Ova substituted or unsubstituted aryloxy) or furthermore the following general formula) % formula % (wherein R1 and R3 and R5 are C1-C8 alkylene or C1-C8 alkoxy, R2 is hydrogen,
01-C8 alkyl, 01-C8 alkoxy, 06-C
+a substituted or unsubstituted aryl, 01-C8 acyloxy is still 06-C+a substituted or unsubstituted aryloxy, R4 and H6 are hydrogen, 01-C6 alkoxy, 01-C8 acyloxy or 06-C+a substituted or unsubstituted aryl A silane coupling agent having a silane coupling agent (selected from oxy) is used alone or in combination.

Among them, preferred silane coupling agents are as follows.

(a) γ-Metaacryloxypropyltrimethoxinelan H3 CH2=C-C, -0-C31hSi(OGHs)s1 (b) γ-glycidoxypropyltrimethoxysilane (c) N-β (aminoethyl ) γ-aminopropyltrimethoxine run HzNCzH4NHC5H6Sj, (OCHs)s)
N-β (agonoethyl) γ-aminopropylmethyldimethoxysilane H2NC2HaNHCsHbSi (OCH3)2Hs (e) γ-aminopropyltriethoxysilane H2N
CsH6Si (OC2Hs)s(to) γ-Mercaptopropyltrimethoxysilane H3CsH6Si (
OCH3)3 (g) γ-Chloroprobyltrimethquine 04C
5H6Si (OGHs)s (t) Vinyltris(β-methoxyethoxy)silane CH2=CH81(OCzH40GH3)s The silane coupling agent referred to here has two or more functional groups in its molecule, and usually The functional groups are silicon compounds having different reactivities.The silane coupling agent can usually be represented by the general formula %. Here, X1 to x5 represent hydrolyzable groups bonded to the St atom, and representative examples thereof include an alkoxy group, an acyloxy group (especially an acetoxy group), and a halogen (especially chlor).

Further, Y represents various organic functional groups, such as vinyl group,
Typical examples are organic functional groups containing amino groups, imino groups, chloro groups, epoxy groups, mercapto groups, peroxy groups, ureido groups, etc., and they are not yet directly bonded to Si atoms via organic groups R. are doing.

The oil-filled capacitor of the present invention is made by impregnating an organosilicon compound with insulating oil containing an effective amount of at least one kind of silane coupling agent, but the effective amount is 0- 0.02 wt% or more, preferably 0.1 wt% or more. 3w
Up to t%, the initial dielectric properties of oil-immersed capacitors at high temperatures become better as the amount added increases, but beyond 3 wt%, the initial dielectric properties do not improve even if the amount added is increased.

However, it exhibits much better initial properties than without additives, and exhibits excellent electrical dielectric properties even with an additive amount of about 10 wt%. Furthermore, when the amount added is increased to 20 to 30 wt%, the initial properties are temporarily poor, but the properties are dramatically improved by voltage aging treatment. However, the current silane coupling agent is extremely expensive, resulting in an extremely expensive oil-immersed capacitor, and at present the preferred range of addition amount is 0.1 wt% to 10 wt%.

As the electrodes constituting the capacitor, electrodes made by directly metallizing a dielectric material by vapor-depositing zinc, aluminum, etc., or aluminum foil are used as electrodes. If the ends of the aluminum foil are folded back and a round edge electrode is used to alleviate the concentration of electric field at the end of the electrode, the effect of suppressing corona discharge can be improved.0 Synthetic resin film or paper can be used as the dielectric material constituting the capacitor. ○ Particularly when using a roughened synthetic resin film (for example, a roughened polypropylene film) that increases impregnability, the dielectric loss of the film itself is small and the impregnability is good, resulting in a high corona initiation voltage and particularly excellent high temperature and high voltage resistance properties. The following is a description of specific embodiments of the present invention.
The figure shows the initial tan δ at 100° C. of the oil-immersed capacitor according to the present invention, and shows only the case where zinc-deposited electrodes are used, which increases the tan δ. The oil-immersed capacitor shown here has the same capacitor electrode configuration as shown in Figure 1, and the insulating oil is impregnated with a low-swelling flame-retardant insulating oil made by adding 1 wt% of γ-methacrylicoxyglopytrimethoxysilane to dimethylpolysiloxane. In the case of capacitor D, 1 wt of methylphenylborisiloxane γ-methacryloxypropyl trimethoxysilane was applied to a capacitor element made by winding two zinc-deposited metallized films around the smooth surface of a single-sided roughened polypropylene film. This is the case of capacitor E impregnated with the added low-swelling flame-retardant insulating oil. Second
As can be seen from the figure, the conventional flame-retardant oil-filled capacitors also exhibit much superior low tan δ characteristics, and these flame-retardant oil-filled capacitors of the present invention can be used at higher temperatures and at a sufficiently higher potential than conventional ones. Can be used at a tilt. Not only is it flame retardant, it has extremely low swelling properties, and the adhesive strength between the thin metal film of the metallized plastic film and the plastic film remains strong for a long period of time, making it an extremely stable oil-immersed capacitor. .

Although the main object of consideration here was an oil-immersed capacitor with electrodes made of zinc, which has particularly poor tanδ characteristics, similar considerations apply to oil-immersed capacitors with electrodes made of aluminum. have an effect.

Effects of the Invention As described above, the present invention has flame retardant properties, extremely low solubility and swelling properties of the plastic film, and further has an unprecedentedly low tan δ characteristic, making it impossible to use conventional capacitors. This provides an excellent effect of providing an oil-immersed capacitor that can be used even under high potential gradients.

[Brief explanation of drawings]

FIG. 1 is an initial tan δ-potential gradient characteristic diagram of a conventional oil-immersed capacitor, and FIG. 2 is an initial tan δ-potential gradient characteristic diagram of an oil-filled capacitor according to an embodiment of the present invention. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 1 ■ Hawk (V/, u)

Claims (1)

[Claims] An oil-immersed capacitor impregnated with insulating oil containing an organosilicon compound and at least one type of silane coupling agent.