JPS59194306A - Oil-immersed condenser - 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 Field of Industrial Application The present invention relates to an oil-immersed capacitor that achieves improved characteristics and a higher potential gradient for use in high voltage applications, power applications, electrical equipment applications, electronic communication applications, etc. be.

Conventional structure and its problems Conventionally, in this type of oil-immersed capacitor, which is equipped with plastic film or insulating paper as a dielectric material, the insulating oil is damaged by thermal or electrical energy, which is a problem when used for a long period of time. Stabilizers such as antioxidants and deterioration inhibitors are mixed into insulating oil for the purpose of suppressing deterioration of the insulating oil and chain reactions caused by the deterioration products, and various stabilizers have been proposed. For example,
Publication No. 239 describes epoxy stabilizers in Japanese Unexamined Patent Publication No. 5
No. 3-35999 proposes mixing a phenol stabilizer and an epoxy stabilizer. These stabilizers have the effect of capturing chlorine and moisture contained in the manufacturing process or decomposition products during use, and suppress the acceleration of deterioration and chain reactions of insulating oil and dielectric materials during long-term life and actual use. However, on the other hand, the more effective these stabilizers are in trapping chlorine, moisture, and decomposition products and suppressing the acceleration of deterioration, the more they have the opposite effect. In addition, the insulation resistance of the insulating oil became low, the dielectric loss tangent value (hereinafter referred to as -δ) also deteriorated, and the -δ characteristic, which is important for oil-immersed capacitors, was likely to deteriorate. In particular, the epoxy stabilizer has a large trapping effect as described above as a stabilizer and has an extremely good deterioration inhibiting effect, but on the other hand, it also has a large degree of deterioration of the δ of the oil-immersed capacitor.

Therefore, conventional oil-immersed capacitors mixed with various stabilizers can suppress deterioration and improve long-term reliability, but in order to make oil-immersed capacitors smaller, they are designed with a higher potential gradient. This was extremely difficult since the heat generation affected by tan δ would become large and cause thermal destruction.

Purpose of the Invention In view of the above-mentioned drawbacks, the present invention provides a small and lightweight oil-immersed capacitor that suppresses the acceleration of deterioration of the oil-immersed capacitor, simultaneously improves the VCt and u+δ characteristics, improves performance, and enables a higher potential gradient design. The purpose is to provide the following.

Structure of the Invention Therefore, the present invention impregnates a capacitor element including at least one plastic film as a thin dielectric between a pair of electrodes with an impregnating oil containing at least an epoxy stabilizer and a silane coupling agent in an insulating oil. This is what I did.

Description of Examples The silane coupling agent used in the present invention has two or more functional groups in its molecule, and the functional groups are usually silicon compounds having different reactivities. This silane coupling agent can generally be represented by the general formula Y RSi X3. Here, xll-i represents a hydrolyzable group bonded to the S1 atom, and is an alkoxy group.

Representative examples include acyloxy groups (especially acetoxy groups) and halogens (especially chlorine). Further, Y represents an organic functional group of each scale, for example, vinyl/shi group.

Representative examples include organic functional groups containing amino groups, imino groups, chloro groups, epoxy groups, mercapto groups, peroxy groups, ureido groups, etc. ing.

Specific examples of the silane coupling agent include γ-methacryloxypropynontrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyl/L'I-'
J-engineering silane, vinyltris(β-methoxyethoxy)silane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)V)γ-7 Minopropyltrimethoxysilane and the like.

The present inventors have conducted research on improving the -δ characteristics of oil-immersed capacitors that are completely impregnated with insulating oil containing an epoxy stabilizer, and have found that the insulating oil contains an epoxy stabilizer and a silane coupling agent such as those listed above. By impregnating the capacitor with impregnating oil, the -δ of the oil-immersed capacitor was significantly improved compared to the conventional one, thereby improving the characteristics and achieving a higher potential gradient.

The amount of silane coupling agent mixed varies depending on the operating humidity and rating of the oil-immersed capacitor, but generally it is 0.1 to 10
Preferably, it is % by weight. If it is less than 0.1% by weight, the above-mentioned dielectric dissipative value will be little improved and it will not be enough to achieve a large potential gradient.
If the value exceeds % by weight, there is no particular problem as the specific resistance value of the insulating oil will only decrease slightly, but from an economic standpoint, this silane coupling agent is extremely expensive, so it should be A small amount is desirable.

Regarding epoxy stabilizers, there have been various types of stabilizers, all of which can be used in the present invention. For example, dipentene dioxide, vinylcyclohexene dioxide.

Bis(2,3)epoxycyclobenzene.

3.4-Epoxycyclohexylmethyl 3.4-Evoxinclohexanecarpoxylate, bis(3,4-epoxy6-methylhexylmethy)V) Atsube-1-,di(2-ethylhexyl/1/)' -4.6 evogycinchlohexane-1.2 dicarboxylene-1, etc.

The amount of the epoxy stabilizer mixed is preferably 0.05% by weight to 10% by weight. If the value is less than 0.05% by weight, almost no effect of suppressing the deterioration of the insulating oil is observed, and if the value exceeds 10% by weight, the -δ improvement effect of oil-immersed capacitors, which is the object of the present invention, will be reduced, and Graduation is not achieved sufficiently.

Insulating oils mixed with these silane coupling agents and epoxy stabilizers include ester insulating oils such as phthalate ester, fumarate ester, maleate ester, fatty acid ester, alkylbenzene, diallylethane, triallyl diethane, etc. Hydrocarbon compounds such as dibenzyltoluene, dialkyldiphenyl, alkylnaphthalene, mineral oil, liquid paraffin, and polybutene.

Next, specific examples of the present invention will be described.

Di(2-ethylhexγ/L/)'-4,5 epoxycyclohexane- was used as an epoxy stabilizer in a capacitor element wound with polypropylene film as a thin dielectric material.
An oil-immersed capacitor impregnated with a phthalate ester mixed with 3% by weight of 1,2 dihydro-bogysylate and 2% by weight of γ-methacryloxypropyltrimethoxysilane as a silane coupling agent, and the epoxy stabilizer. Oil-immersed capacitor B is impregnated with phthalate ester mixed with the same amount of phthalate ester, and oil-immersed capacitor C is impregnated with phthalate ester without epoxy stabilizer or silane coupling agent mixed in.
A high voltage (,1
20v/lL) was applied and a life test was performed.
As shown in Figure 1, all of capacitor C was destroyed within 100 hours, but most of capacitor B was intact even after 1000 hours. Note that A and B in FIG.

C is the characteristic of capacitors A, B, and C, respectively.

This shows that in the present invention, even if a silane coupling agent and an epoxy stabilizer are mixed, the above-mentioned trapping effect and deterioration suppressing effect of the epoxy stabilizer are sufficiently achieved. Furthermore, the results of measuring the voltage characteristics of tan δ at 100″CK for i'lfl immersion capacitors A and BK are shown in FIG.

These results show that in the conventional oil-immersed capacitor B, which is impregnated with phthalate ester and mixed only with an epoxy stabilizer, -δ increases significantly in the high voltage range, whereas in the oil-immersed capacitor A of the present invention, it is clear that -δ increases significantly in the high voltage range. It was observed that -δ became small and very good Peng δ characteristics were obtained. Figure 553 is 80℃
The results of the relationship between the voltage applied to oil-immersed capacitors A and B in an atmosphere and the time until their breakdown (characterized by V-) are shown.

As a result, as is clear from FIG. 3, the oil immersion method of the present invention was confirmed.

Note that almost similar effects were observed with other silane coupling agents and epoxy stabilizers.

Furthermore, similar effects were obtained with other ester insulating oils and other hydrocarbon compound insulating oils.

Effects of the Invention As described above, according to the present invention, an oil-immersed capacitor containing at least one plastic film as a thin dielectric can be prevented from accelerating deterioration and chain reactions caused by decomposition products, and can provide a highly reliable capacitor. We provide capacitors with good −δ characteristics and enable high potential gradient designs.
This has the excellent effect of realizing a small and light oil-immersed capacitor.

[Brief explanation of drawings]

FIG. 1 is an applied voltage one-hour characteristic diagram of an oil-immersed conde capacitor according to an embodiment of the present invention and a conventional product. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 11I Temple CHrji Figure 2 □ Electrician

Claims (1)

[Claims] An oil-immersed capacitor in which a capacitor element including at least one plastic film as a thin dielectric between a pair of electrodes is impregnated with impregnating oil containing at least an epoxy stabilizer and a silane coupling agent in insulating oil.