JPS6035408A - Electrically insulating oil - 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 The present invention relates to electrical insulating oil used in electrical equipment such as capacitors and transformers. By mixing alkylnaphthalene (hereinafter referred to as AN) or other aromatic hydrocarbon compounds, the low-temperature properties of vegetable oil can be improved and highly reliable electrical equipment can be obtained. This is what we are trying to provide.

Conventionally, hydrocarbon-based insulating oils such as mineral oil, alkylbenzene, and bolybdenum have been used as electrical insulating oils.

However, although these hydrocarbon-based insulating oils are relatively thermally stable, they have a drawback in that their dielectric constant is low and there is no room for improvement in terms of rationalization of design. As a solution to this drawback, a method of using vegetable oil as an electrical insulating oil has been considered in the past. Vegetable oil has a high dielectric constant of 3.1 to 4.5 (compared to conventional insulating oil), and polypropylene film (hereinafter referred to as PP film), which is widely used as an oil-immersed material, has a small swelling, making it suitable for use in oil-immersed capacitors, etc. It also has the feature of improving the impregnating property between dielectric layers.

There are various types of vegetable oils, but among them, those used as insulating oils are non-drying oils or semi-drying oils, which have good electrical properties, low viscosity, and low pour points. Table 1 shows the properties of some vegetable oils that can be used as insulating oils. Among them, castor oil has the lowest pour point, but it has a high viscosity and is unsuitable for impregnating insulating materials such as PP film and Buchnutik film, so rapeseed oil has a low pour point and is superior. It is thought that

However, even though the pour point of rapeseed oil is low, it is
'c, and the pour point of conventional insulating oils (mineral oil -35°C, alkylbenzene -60°C, polybutene -45'C, etc.)
It is very expensive, making it impossible to use electrical equipment stably at low temperatures, especially at -20''C or lower.

In this way, it is necessary to improve the pour point of rapeseed oil.

Therefore, the present invention has found that it is effective to lower the pour point by mixing alkylbenzene, diarylethane, alkylnaphthalene, or other aromatic hydrocarbon compounds having a pour point of 130'C or less with rapeseed oil. Confirmed experimentally. Furthermore, the proportion of aromatic compounds is 30 to 5 Q
The suitability of VO1% will be explained below using experimental data.

Figure 1 shows rapeseed oil mixed with AB (curve ■ in the figure), oil mixed with I) A E (curve ■ in the figure), oil mixed with AN (curve ■ in the figure), and alkyldiphenyl. (hereinafter referred to as A I)) (curve ■ in the figure) and oil mixed with polybutene (curve ■ in the figure) are shown in Table 9. (JIS C2 for flow
101) lower than the pour point of rapeseed oil,
For example, mixing the above compounds lowers the pour point. Furthermore, it has been found that mixing aromatic hydrocarbon compounds such as AB%DAE, AN, and AD has a greater pour point lowering effect than mixing an aliphatic hydrocarbon compound S such as polybutene.

FIG. 2 shows the pour point of oil prepared by mixing rapeseed oil with 3 Q vol 1% of an aromatic hydrocarbon compound having a comparable pour point. The pour point reduction of rapeseed oil is most effective when mixed with an aromatic hydrocarbon compound having a pour point of -30°C or lower.

From the above results, we confirmed that by lowering the pour point of rapeseed oil, the influence of the lowered pour point on the 'N and mechanical properties of the rapeseed oil was confirmed.

Figure 3 shows the corona onset 'tortoise pressure at -20'C of a 30 μF model capacitor in which a capacitor element with double-sided gold-covered paper as electrodes and PP film as dielectric is impregnated with rapeseed oil and AB mixed oil. It is. When the mixing ratio of AB is 20 to 50 vol%, the corona onset voltage is higher than that of rapeseed oil alone, and the effect of lowering the pour point appears.

Figure 4 shows the swelling ratio of the PP film in a mixed oil of rapeseed oil and an aromatic hydrocarbon compound. The swelling ratio is the saturated thickness change of the PP film at 90'c. The swelling rate of aromatic hydrocarbon compounds is 3 to 4 times greater than that of rapeseed oil, so
As the amount of aromatic hydrocarbon compound mixed increases, the swelling ratio of the mixed oil also increases. In Figure 3, the mixing ratio of AB is 50vo
At 1% or more, the corona onset voltage decreases not because of the pour point problem, but because the swelling of the PP film increases, resulting in a decrease in the interlayer retention in the capacitor element.

Although rapeseed oil is effective as a solution to the drawbacks of conventional electrical insulating oils, it was found that the pour point should be improved, and as a method to do so, aromatic hydrocarbon compounds with a pour point of -30°C or less were developed. It was discovered that it is effective to mix 20 to 50 vol% of this with rapeseed oil. Experiments have been conducted on aromatic hydrocarbon compounds using AB, DAE%AN, and AD, but this is not the only option; other aromatic hydrocarbon compounds can be used as long as the pour point is 130"C or lower. A similar effect can be obtained by using a compound.

As described above, when the electrical insulating oil of the present invention is used, it is possible to reduce the swelling of PP film, which is widely used as an oil-immersed insulating material, by not having a high specific electric current, and to ensure fluidity at low temperatures. , it has made a great contribution to industry by improving the reliability of electrical equipment.

[Brief explanation of the drawing]

Figure 1 is a mixture ratio of various compounds in rapeseed oil - pour point characteristic diagram, Figure 2 is an aromatic hydrocarbon compound - pour point characteristic diagram of an oil obtained by mixing rapeseed oil with 30 vol % of aromatic hydrocarbon compounds, Figure 3 shows the mixing ratio of alkylbenzene to rapeseed oil.
FIG. 4 is a characteristic diagram of the corona start voltage/rated voltage characteristic of the capacitor, and a characteristic diagram of the mixing ratio of an aromatic hydrocarbon compound to rapeseed oil versus the swelling rate. Patent applicant Nippon Capacitor Industry Co., Ltd. Q 20 40 60 90 1
, 4 shi middle E ibis, 4 chi 乍gu. Go 3・Scold (vd, n [] Fig. 3 0 25 !; 0 7 tan lθθ *N m, Jshi't v yd n tr n LiQ7
1 day Bi, (Va",?)Fig. ;
] 2, (Vd Li Procedural Amendments Imported) 1 Indication of the case Patent Application No. 1442418 filed in 1982 2 Title of the invention 14i, Kisin Song 3 Relationship with the famous case for which the amendment is made A brief explanation of the patent applicant 5. Contents of amendment (1) Line 15 of page 1 of the specification is corrected as follows. "Naphthalene (hereinafter referred to as AN), alkylsiphenylene/I/ (hereinafter referred to as AD) or others" (2) Lines 5-6 of page 4 of the specification are corrected as follows. Oil mixed with rAN (curve ■ in the figure), oil mixed with AD (in the figure) (3) "Electrical equipment" in page 1, item 15 of the specification is corrected to "capacitor". (4) Specification No. Page 5, lines 7 and 8 are corrected as follows: ``A 30 μF model capacitor in which a capacitor element made of 18 μm sheets of aluminum is impregnated with a mixed oil of rapeseed oil and AB, and a mixture of rapeseed oil and DAE?!-oil. (5) Line 13 of page 5 of the specification is corrected as follows: ``Figure 4 shows a mixed oil of rapeseed oil and AB, a mixture of rapeseed oil and DA
One 20″ of lOμF capacitor impregnated with mixed oil of E.
It shows the corona onset voltage at C. Figure 5 shows a mixture of rapeseed oil and aromatic hydrocarbon compounds. (6) Line 19 of page 5 of the specification is corrected as follows. "Yes. In Figures 3 and 4, the mixing ratio of AB is 50vo1%.
(7) Ming Glaze f - Insert the following sentence between the 3rd and 4th lines of page 6. ``Next, Figure 6 shows the survival rate of the capacitor when a voltage of 13 times the rated voltage was applied at -20'C, and the life test was carried out using the same type of capacitor used in Figure 3. Rapeseed oil and AB10vo 1% mixed oil ■, rapeseed oil and AB30vo 1% mixed oil ■ and AB50vo
The capacitor impregnated with 1% mixed oil ■ had a survival rate of 100% even after 1000 hours. Furthermore, Fig. 7 shows the residual rate of the capacitor when a voltage 2.5 times the rated voltage is applied at 90'C.
The survival rate of a capacitor impregnated with 1% mixed oil is 1000
It remained 100% even after hours. (8) Lines 7 to 9 of page 7 of the specification are corrected as follows. "Heavy pressure / rated voltage characteristic diagram, Figure 4 is the mixing ratio of aromatic hydrocarbon purple oil to rapeseed oil - corona onset voltage of capacitor / rated voltage characteristic factor, No. 51 Mixing ratio of aromatic hydrocarbon compound to rapeseed oil - The swelling rate characteristic diagrams, Figures 6 and 7, are within the life characteristics of the capacitor.'' (9) Figure 3 is corrected as shown in the attached sheet. α0) Correct Figure 4 to Figure 5. (11) Add Figures 4, 6, and 7 as attached. L(5-ratio(\be, 1.right'Igd;h
, J4u(b!'t4tala, ah ratio(vol, 2
)Fig.
Tsuba to Masuhi (yol, 5≦'9 Figure 6 Figure 17 Imazaki Ken (hr) Procedural amendment (voluntary) 1. Indication of the case 1982 Patent application No. 14424 January 2 Name of the invention Electrical insulating oil 3 , Related to the old case to be amended Patent applicant 4, i1i correct subject "Meishu (detailed explanation column of the invention of shoes)" 5 "30-50" on page 3, line 20 of the description of the contents of the amendment ``20~50
Correct it with J.

Claims (1)

[Claims] 20 to 5% of sulfalkylbenzene, diarylethane, alkylnaphthalene, or other aromatic hydrocarbon compounds having a pour point of below 30°C are added to rapeseed oil, which is a vegetable oil.
An electrical insulating oil characterized by being mixed within a range of 0 to 1%.