JP2006278916A - Method for suppressing deterioration in insulating paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for suppressing deterioration in insulating paper that makes it possible to easily and inexpensively suppress deterioration in the insulating paper used in oil-filled electrical machinery and apparatus. <P>SOLUTION: In an electrical apparatus 1, conductive members 11 and 12 in contact with each other are insulated from each other by insulating paper. The insulating paper is immersed in electrical insulating oil 13 containing hydrocarbon base oil and aminic compound and/or phenolic compound. Thus, deterioration in the insulating paper is sufficiently suppressed by the action of the aminic compound and/or phenolic compound. Therefore, the electric insulation between the conductive members 11 and 12 can be kept at a high level for a long time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for operating an electrical device.

  Conventionally, in oil-filled electrical equipment such as oil-filled transformers and oil-filled reactors, a solid insulator and electrical insulating oil are used for insulation between conductive members. For example, in the case of an oil-filled transformer, a solid insulator is interposed between an iron core and a winding, and the insulation between the iron core and the winding is achieved by immersing them in electric insulating oil. (For example, see Patent Document 1.)

  Examples of the solid insulator include insulating paper made of natural / synthetic fibers, mica, asbestos, glass fiber, etc. Among them, insulating paper is widely used because it is inexpensive and easy to use (for example, non-patent See reference 1.)

Further, as the electrical insulating oil, in order to ensure the electrical insulation, it is common to use a highly refined mineral oil base oil or a synthetic base oil such as alkylbenzene or polyolefin. (For example, see Patent Documents 2 and 3.)
JP 2001-143933 A JP-A-6-325622 JP-A-9-279160 "Electrical Insulating Paper", Corona, Chapter 1, Pages 1-2, 1969

  By the way, in oil-filled electrical equipment using insulating paper as a solid insulator, when internal heating or discharge occurs inside, the insulating paper or electrical insulating oil gradually deteriorates, resulting in a decrease in dielectric strength, and finally dielectric breakdown. It is feared that it will lead to And the lifetime of such a hydraulic voltage apparatus is more dependent on the deterioration of insulating paper than electrical insulating oil.

  Therefore, from the standpoint of extending the life of oil-filled electrical equipment, the use of special solid insulators (eg, epoxy resins) with excellent durability has been proposed, but many of these solid insulators are expensive. In addition, since it is difficult to apply to existing electrical equipment, it cannot be a fundamental solution. In addition, as for electrical insulating oil, as described in Patent Documents 2 and 3 above, although some studies have been made on technology for suppressing deterioration of the electrical insulating oil itself, examination from the viewpoint of suppressing deterioration of insulating paper. Is not done enough.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for suppressing deterioration of insulating paper that can suppress deterioration of insulating paper included in oil-filled electrical equipment easily and inexpensively. And

  In order to solve the above-mentioned problems, the present invention includes a hydrocarbon base oil and an amine compound and / or a phenol compound in an electrical device in which conductive members are insulated with insulating paper. Provided is a method for suppressing deterioration of insulating paper, characterized by being immersed in an electric insulating oil.

  In the method for inhibiting deterioration of insulating paper of the present invention, an amine compound and / or phenol is obtained by immersing the insulating paper in an electric insulating oil containing a hydrocarbon base oil and an amine compound and / or a phenol compound. Since the deterioration of the insulating paper is sufficiently suppressed by the action of the system compound, the electrical insulation between the conductive members can be maintained at a high level over a long period of time. Therefore, according to the present invention, it is possible to easily extend the life of the electric device at a low cost.

  According to the method for suppressing deterioration of insulating paper of the present invention, it is possible to suppress deterioration of insulating paper included in an oil-filled electrical device easily and inexpensively.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be.

  FIG. 1 is a schematic cross-sectional view showing an example of an oil-filled electrical device (oil-filled transformer) to which the present invention is applied. In the oil-filled transformer 1 shown in FIG. 1, an iron core 11, a winding 12 wound around the iron core 11, and a sufficient amount of electrical insulation to immerse the iron core 11 and the winding 12 in a tank 10. Oil 13 is contained. A tank cover 15 having a bushing 14 is provided on the upper portion of the tank 10.

  The winding 12 is covered with insulating paper, and the iron core 11 and the winding 12 are insulated by the insulating paper and the electrical insulating oil 13. The insulating paper is mainly composed of natural or synthetic fibers, and the insulating paper may be subjected to a predetermined chemical treatment. Specific examples of insulating paper include pulp such as kraft pulp, cellulose-derived paper such as cyanoethylated paper and acetylated paper, chemical-added paper such as amine-added paper, morpholine-added paper, and activated alumina-added paper, or DuPont Synthetic fiber paper such as sexual Nomex Pater.

  The electrical insulating oil 13 is an electrical insulating oil containing a hydrocarbon base oil and an amine compound and / or a phenol compound. Hereinafter, each component of the electrical insulating oil 13 will be described in detail.

  The hydrocarbon base oil contained in the electrical insulating oil 13 may be either a mineral base oil or a synthetic base oil. Specifically, as the mineral oil base oil, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and vacuum distillation is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, Examples thereof include paraffinic mineral oil and naphthenic mineral oil that are refined by appropriately combining hydrotreating, sulfuric acid washing, and clay treatment. Specific examples of synthetic base oils include poly α-olefins (polybutene, 1-octene oligomers, 1-decene oligomers, etc.), polybutenes, alkylbenzenes, alkylnaphthalenes, alkyldiphenylalkanes (alkyldiphenylethanes, alkyls). And hydrocarbon synthetic oils such as alkyl biphenyl and the like. Of the above base oils, highly refined mineral oils such as hydrocracked mineral oils and hydrocarbon-based synthetic oils are preferable in that they have a high impact breakdown voltage and a small adverse effect on insulating paper.

In the present invention, one of the above-described hydrocarbon base oils may be used alone, or two or more may be used in combination at any mixing ratio. Further, the viscosity of the base oil according to the present invention is optional, preferably a kinematic viscosity at 40 ° C. is 1 to 50 mm ² / s, more preferably 3~40mm ² / s, 5~30mm More preferably, it is ² / s.

  When the electrical insulating oil 13 contains a phenolic compound, examples of the phenolic compound include phenyl-α-naphthylamine compounds, dialkyldiphenylamine compounds, benzylamine compounds, and polyamine compounds. α-Naphthylamine compounds and alkyldiphenylamine compounds are preferred.

［式（１）中、Ｒ^１は水素原子又は炭素数１〜１６の直鎖状若しくは分枝状のアルキル基を示す。］ As the phenyl-α-naphthylamine compound, phenyl-α-naphthylamine represented by the following general formula (1) is preferably used.

[In formula (1), R ¹ represents a hydrogen atom or a linear or branched alkyl group having ^{1 to} 16 carbon atoms. ]

When R ¹ in the general formula (1) is an alkyl group, the alkyl group is linear or branched having 1 to 16 carbon atoms as described above. Specific examples of such an alkyl group include, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, A tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, and the like (these alkyl groups may be linear or branched). The ratio of functional groups occupied in the molecule is small when the number of carbon atoms of R ¹ exceeds 16, the deterioration suppression effect of the insulating paper tends to decrease.

When R ¹ in the general formula (1) is an alkyl group, from the viewpoint of excellent solubility in base oil, R ¹ is preferably a branched alkyl group having 8 to 16 carbon atoms, and further having 3 or 4 carbon atoms. A branched alkyl group having 8 to 16 carbon atoms derived from an olefin oligomer is more preferred. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene, and isobutylene, and propylene or isobutylene is preferable from the viewpoint of excellent solubility. In order to obtain better solubility, R ¹ is derived from a branched octyl group derived from a dimer of isobutylene, a branched nonyl group derived from a trimer of propylene, or a trimer of isobutylene. Even more preferred are branched dodecyl groups, branched dodecyl groups derived from propylene tetramers, or branched pentadecyl groups derived from propylene pentamers, and branches derived from isobutylene dimers. An octyl group, a branched dodecyl group derived from a trimer of isobutylene, or a branched dodecyl group derived from a tetramer of propylene is particularly preferred.

  As phenyl-α-naphthylamine represented by the general formula (4), a commercially available product may be used, or a synthetic product may be used. The synthesized product is a reaction between phenyl-α-naphthylamine and a halogenated alkyl compound having 1 to 16 carbon atoms, or phenyl-α-naphthylamine and an olefin or carbon number having 2 to 16 carbon atoms, using a Friedel-Crafts catalyst. It can be easily synthesized by reacting with 2 to 16 olefin oligomers. Specific examples of Friedel-Crafts catalysts include metal halides such as aluminum chloride, zinc chloride, and iron chloride; acidic catalysts such as sulfuric acid, phosphoric acid, phosphorus pentoxide, boron fluoride, acidic clay, and activated clay. Etc. can be used.

［式（２）中、Ｒ^１５及びＲ^１６は同一でも異なっていてもよく、それぞれ炭素数１〜１６のアルキル基を示す。］ As the dialkyldiphenylamine compound, p, p′-dialkyldiphenylamine represented by the following general formula (2) is preferably used.

[In formula (2), R ¹⁵ and R ¹⁶ may be the same or different and each represents an alkyl group having 1 to 16 carbon atoms. ]

Specific examples of the alkyl group represented by R ² and R ³ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, and undecyl. Group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group and the like (these alkyl groups may be linear or branched). Among these, R ² and R ³ are preferably branched alkyl groups having 3 to 16 carbon atoms, and olefins having 3 or 4 carbon atoms, or the like thereof, from the viewpoint that deterioration of insulating paper at high temperatures can be suppressed over a long period of time. A branched alkyl group having 3 to 16 carbon atoms derived from an oligomer is more preferable. Specific examples of the olefin having 3 or 4 carbon atoms include propylene, 1-butene, 2-butene, and isobutylene. Propylene or isobutylene is preferable because it can suppress deterioration of insulating paper at high temperatures for a longer period of time. Is preferred. In addition, R ² or R ³ is derived from an isopropyl group derived from propylene, a tert-butyl group derived from isobutylene, or a dimer of propylene, since further excellent antioxidant properties can be obtained. Branched hexyl group, branched octyl group derived from isobutylene dimer, branched nonyl group derived from propylene trimer, branched dodecyl group derived from isobutylene trimer, propylene 4 Even more preferred are branched dodecyl groups derived from dimers or branched pentadecyl groups derived from pentamers of propylene, tert-butyl groups derived from isobutylene, branches derived from dimers of propylene Hexyl group, branched octyl group derived from isobutylene dimer, branched nonyl derived from propylene trimer , A branched dodecyl group derived from a tetramer of branched dodecyl or propylene derived from a trimer of isobutylene being most preferred.

When a compound in which one or both of R ² and R ³ are hydrogen atoms is used, sludge may be generated due to oxidation of the compound itself. Moreover, when the carbon number of the alkyl group exceeds 16, the proportion of the functional group in the molecule becomes small, and the effect of suppressing deterioration of the insulating paper at high temperature may be reduced.

  As the p, p'-dialkyldiphenylamine represented by the general formula (2), a commercially available product may be used, or a synthesized product may be used. The synthesized product uses a Friedel-Crafts catalyst, reaction of diphenylamine, a C1-C16 halogenated alkyl compound and diphenylamine, or diphenylamine and a C2-C16 olefin, a C2-C16 olefin, or these It can be easily synthesized by reacting with the above oligomer. As the Friedel-Crafts catalyst, metal halides and acidic catalysts exemplified in the description of phenyl-α-naphthylamine are used.

  The compounds represented by the general formulas (1) and (2) are both aromatic amines. These aromatic amines may be used singly or as a mixture of two or more different structures, but from the point that deterioration of insulating paper at high temperatures can be suppressed over a longer period, It is preferable to use together phenyl-α-naphthylamine represented by (1) and p, p′-dialkyldiphenylamine represented by the general formula (2). The mixing ratio in this case is arbitrary, but is preferably in the range of 1/10 to 10/1 by mass ratio.

［式（３）中、Ｒ^４は炭素数１〜４のアルキル基を示し、Ｒ^５は水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^６は水素原子、炭素数１〜４のアルキル基、下記一般式（ｉ）又は（ｉｉ）：

（一般式（ｉ）中、Ｒ^７は炭素数１〜６のアルキレン基を示し、Ｒ^８は炭素数１〜２４のアルキル基又はアルケニル基を示す。）

（一般式（ｉｉ）中、Ｒ^９は炭素数１〜６のアルキレン基を示し、Ｒ^１０は炭素数１〜４のアルキル基を示し、Ｒ^１１は水素原子又は炭素数１〜４のアルキル基を示し、ｋは０又は１を示す。）
で表される基を示す。］

［一般式（４）中、Ｒ^１２及びＲ^１４は同一でも異なっていてもよく、それぞれ炭素数１〜４のアルキル基を示し、Ｒ^１３及びＲ^１５は同一でも異なっていてもよく、それぞれ水素原子又は炭素数１〜４のアルキル基を示し、Ｒ^１６及びＲ^１７は同一でも異なっていてもよく、それぞれ炭素数１〜６のアルキレン基を示し、Ａは炭素数１〜１８のアルキレン基又は下記の一般式（ｉｉｉ）： When the electrical insulating oil 13 contains a phenolic compound, the phenolic compound is selected from, for example, compounds represented by the following general formula (3), general formula (4), and general formula (5). At least one alkylphenol compound is preferred.

[In Formula (3), R ⁴ represents an alkyl group having 1 to 4 carbon atoms, R ⁵ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ⁶ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. An alkyl group, the following general formula (i) or (ii):

(In general formula (i), R ⁷ represents an alkylene group having 1 to 6 carbon atoms, and R ⁸ represents an alkyl group or alkenyl group having 1 to 24 carbon atoms.)

(In General Formula (ii), R ⁹ represents an alkylene group having 1 to 6 carbon atoms, R ¹⁰ represents an alkyl group having 1 to 4 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. And k represents 0 or 1.)
The group represented by these is shown. ]

[In General Formula (4), R ¹² and R ¹⁴ may be the same or different and each represents an alkyl group having 1 to 4 carbon atoms; R ¹³ and R ¹⁵ may be the same or different; Represents an atom or an alkyl group having 1 to 4 carbon atoms, R ¹⁶ and R ¹⁷ may be the same or different, each represents an alkylene group having 1 to 6 carbon atoms, and A represents an alkylene group having 1 to 18 carbon atoms or The following general formula (iii):

—R ¹⁸ —S—R ¹⁹ — (iii)
(In general formula (iii), R ¹⁸ and R ¹⁹ may be the same or different and each represents an alkylene group having 1 to 6 carbon atoms)
The group represented by these is shown. ]

（一般式（ｉｖ）中、Ｒ^２３及びＲ^２４は同一でも異なっていてもよく、それぞれ炭素数１〜６のアルキレン基を示す。）
で表される基を示す。］ In General Formula (5), R ²⁰ represents an alkyl group having 1 to 4 carbon atoms, R ²¹ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R ²² represents an alkylene group having 1 to 6 carbon atoms or The following general formula (iv):

(In general formula (iv), R ²³ and R ²⁴ may be the same or different and each represents an alkylene group having 1 to 6 carbon atoms.)
The group represented by these is shown. ]

In the compound represented by the above general formula (3), when R ⁶ is a group represented by the general formula (i), R ⁷ in the general formula (i) is an alkylene group having 1 to 2 carbon atoms. R ⁸ is more preferably a linear or branched alkyl group having 6 to 12 carbon atoms, R ^{7 in the} general formula (i) is an alkylene group having 1 to 2 carbon atoms, and R ⁸ Is particularly preferably a branched alkyl group having 6 to 12 carbon atoms.

  Preferred compounds among the compounds represented by the general formula (3) are shown below.

Examples of the compound when R ⁶ is an alkyl group having 1 to 4 carbon atoms include 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butyl-4-ethylphenol, etc. Can be mentioned.

Examples of the compound when R ⁶ is a group represented by the general formula (i) include the following. N-hexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, isohexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, (3-methyl-5-tert-butyl) -4-hydroxyphenyl) acetic acid n-heptyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isoheptyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate n-octyl Isooctyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, 2-ethylhexyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate, (3-methyl-5-tert- Butyl-4-hydroxyphenyl) acetic acid n-nonyl, (3-methyl-5-tert-butyl-4 Hydroxyphenyl) isononyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetate n-decyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isodecyl acetate, (3-methyl -5-tert-butyl-4-hydroxyphenyl) acetic acid n-undecyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) acetoisodecyl, (3-methyl-5-tert-butyl-4-hydroxy) Phenyl) acetate n-dodecyl, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isododecyl acetate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate n-hexyl, (3 -Methyl-5-tert-butyl-4-hydroxyphenyl) propionic acid Hexyl, n-heptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, isoheptyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5 -Tert-butyl-4-hydroxyphenyl) n-octylpropionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isooctylpropionate, (3-methyl-5-tert-butyl-4-hydroxy) 2-ethylhexyl (phenyl) propionate, n-nonyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, isononyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert-butyl-4-hydroxyl N-decyl propionate, (3-methyl-5-tert-butyl-4-hydroxyphenyl) isodecyl propionate, n-undecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, Isoundecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, n-dodecyl (3-methyl-5-tert-butyl-4-hydroxyphenyl) propionate, (3-methyl-5-tert -Butyl-4-hydroxyphenyl) isododecyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate n-hexyl, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid Isohexyl, (3,5-di-tert-butyl-4-hydroxyphenyl N-heptyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) isoheptyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate n-octyl, (3,5- Di-tert-butyl-4-hydroxyphenyl) isooctyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetic acid 2-ethylhexyl, (3,5-di-tert-butyl-4-hydroxyphenyl) ) N-nonyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) isononyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate n-decyl, (3,5 -Di-tert-butyl-4-hydroxyphenyl) isodecyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) N-undecyl acid, (3,5-di-tert-butyl-4-hydroxyphenyl) isoundecyl acetate, (3,5-di-tert-butyl-4-hydroxyphenyl) acetate n-dodecyl, (3,5- Di-tert-butyl-4-hydroxyphenyl) isododecyl acetate, n-hexyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert-butyl-4-hydroxy) (Phenyl) isohexylpropionate, (3,5-di-tert-butyl-4-hydroxyphenyl) n-heptylpropionate, (3,5-di-tert-butyl-4-hydroxyphenyl) isoheptylpropionate, (3 , 5-Di-tert-butyl-4-hydroxyphenyl) propionate n-octyl, (3,5-di- tert-butyl-4-hydroxyphenyl) isooctylpropionate, 2-ethylhexyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) ) N-nonyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) isononyl propionate, (3,5-di-tert-butyl-4-hydroxyphenyl) n-decyl propionate, ( Isodecyl 3,5-di-tert-butyl-4-hydroxyphenyl) propionate, n-undecyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, (3,5-di-tert- Butyl-4-hydroxyphenyl) isoundecyl propionate, (3,5-di-tert Butyl-4-hydroxyphenyl) propionic acid n- dodecyl, and (3,5-di -tert- butyl-4-hydroxyphenyl) isododecyl propionate.

Examples of the compound when R ⁶ is a group represented by the general formula (ii) include bis (3,5-di-tert-butyl-4-hydroxyphenyl), bis (3,5-di-tert). -Butyl-4-hydroxyphenyl) methane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) ethane, 1,2-bis (3,5-di-tert-butyl-4) -Hydroxyphenyl) ethane, 1,1-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 1,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) Propane, 1,3-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-di-tert-butyl-4-hydroxyphenyl) propane and the like; and This A mixture of two or more of these may be used.

  Next, the alkylphenol represented by the general formula (4) will be described.

A particularly preferable compound when A in the general formula (4) is an alkylene group having 1 to 18 carbon atoms is a compound represented by the following formula (4-1).

A particularly preferred compound in the case where A in the general formula (4) is a group represented by the formula (iii) is a compound represented by the following formula (4-2).

  Next, the alkylphenol represented by the general formula (5) will be described.

Specifically preferable as the alkylphenol represented by the general formula (5) is a compound represented by the following formula (5-1) or (5-2).

  The electrical insulating oil 13 may contain only one of an amine compound and a phenol compound, or may contain both an amine compound and a phenol compound, but considering the adverse effect on the performance of the insulating paper. Then, it is preferable to use a phenol type compound. The total content of the amine compound and the phenol compound is preferably 0.01 to 5% by mass, more preferably 0.1 to 0.5% by mass, based on the total amount of the electrical insulating oil 13. When the total content is less than the lower limit value, the effect of suppressing the deterioration of the insulating paper tends to be insufficient, and when the upper limit value is exceeded, the performance of the insulating paper tends to be adversely affected.

  The electrical insulating oil 13 may be composed of the above hydrocarbon base oil and an amine-based compound and / or a phenol-based compound, but further contains a known additive for electrical insulating oil as necessary. May be. Specific examples of such additives include fluid antistatic agents such as benzotriazole; condensates of chlorinated paraffin and naphthalene, polymethacrylates, olefin polymers (including ethylene-propylene copolymers, alkylated polystyrenes, etc.), etc. Pour point depressants; nitrogen-containing heterocyclic compounds such as indolizine, isoindole, indole, 4H-quinolidine, carbazole, indoline, isoindoline, and the like. Although the content of these additives is arbitrary, the total content of the additives is 5% by mass or less based on the total amount of the electrical insulating oil 13 from the viewpoint of suppressing adverse effects on the insulating paper. Is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

The kinematic viscosity of the electrical insulating oil 13 is not particularly limited, it preferably has a kinematic viscosity at 40 ° C. is 1 to 50 mm ² / s, more preferably ^{3~40mm 2 / s, 5~30mm 2 /} s More preferably.

  According to the above embodiment, by immersing the insulating paper that insulates the iron core 11 and the winding 12 in the electrical insulating oil 13, deterioration of the insulating paper is sufficiently suppressed by the action of the amine compound and / or the phenol compound. Therefore, the electrical insulation between the iron core 11 and the winding 12 can be maintained at a high level over a long period of time, and as a result, the life of the oil-filled transformer 1 can be increased.

  The present invention is not limited to the above embodiment. For example, the oil-filled electrical equipment to which the present invention is applied is not particularly limited as long as it can immerse between conductive members intervening insulating paper in electrical insulating oil, and is not limited to a power plant, factory, large-scale facility. It can be preferably applied to various transformers installed outdoors in high voltage devices such as high voltage cables, high voltage circuit breakers, condensers, and transformers.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example at all.

[Example 1]
An electrical insulating oil having the composition shown in Table 1 was prepared using the base oil and additives shown below.
Base oil 1: Naphthenic mineral oil (kinematic viscosity at 40 ° C .: 7 mm ² / s,% CN: 70)
Base oil 2: Branched alkylbenzene (kinematic viscosity at 40 ° C .: 7 mm ² / s)
Additive 1: 2,6-di-tert-butyl-p-cresol.

  Next, insulating paper (cyanoethylated paper, 15 mm × 160 mm × 70 μm, product name: permalex, manufactured by GE) and copper plate (15 mm × 175 mm × 0.2 mm) that have been dehydrated in advance are placed in a 100 ml capacity test tube. Then, 100 ml of the above electric insulating oil was injected by vacuum oiling while vacuum degassing the inside of the test tube.

  The test tube was put in a stainless steel container having an open top and opened, and the opening of the stainless steel container was covered with a top plate. In addition, in order to ensure the space | gap for ventilation | gas_flowing on the opening side of a stainless steel container, the top plate was spaced apart and arrange | positioned with respect to the stainless steel container. The distance between the lower surface of the top plate and the upper end of the stainless steel container was 2 mm. Thus, the stainless steel container in which the test tube was accommodated was placed in a 150 ° C. air constant temperature bath and heated for 15 days. Thereafter, the insulating paper was taken out from the test tube, and the electric insulating oil adhered thereto was removed by solvent cleaning.

The insulating paper thus heat-treated was measured for tensile strength according to JIS P 8113, and the residual tensile strength was determined according to the following formula. The obtained results are shown in Table 1.
(Remaining tensile strength [%]) = {(Tensile strength after heat treatment) / (Tensile strength before heat treatment)} × 100.

[Comparative Example 1]
First, using the base oil 1 and the base oil 2 described above, an electrical insulating oil having the composition shown in Table 1 was prepared. Next, heat treatment was performed in the same manner as in Example 1 except that the obtained electrical insulating oil was used, and the residual tensile strength of the insulating paper after the heat treatment was determined. The obtained results are shown in Table 1.

  As shown in Table 1, in Example 1, it was confirmed that deterioration of the insulating paper was sufficiently suppressed by the electrical insulating oil containing the phenolic compound.

It is a schematic cross section which shows an example of an oil-filled electrical apparatus (oil-filled transformer).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Oil-filled transformer, 10 ... Tank, 11 ... Iron core, 12 ... Winding, 13 ... Electrical insulation oil, 14 ... Bushing, 15 ... Tank cover.

Claims (1)

In an electrical device in which conductive members are insulated by insulating paper, the insulating paper is immersed in an electrical insulating oil containing a hydrocarbon base oil and an amine compound and / or a phenol compound. Insulation paper deterioration control method.

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