JPS6015087B2 - capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a capacitor in which a capacitor element containing a biaxially oriented polypropylene film as a thin dielectric is impregnated with insulating oil.

This type of capacitor is usually constructed using an organic insulator as an insulating oil or a thin dielectric material.

However, such organic insulators deteriorate due to thermal and electrical energy during use, and the resulting deterioration products cause a chain reaction that accelerates the deterioration of the organic insulators and impairs their insulation properties. As a result, it has been difficult to use this type of capacitor for a long period of time as a result of deterioration of electrical properties such as dielectric properties. In view of the above-mentioned problems, this invention extends the life of this type of capacitor by mixing a phosphite stabilizer into the insulating oil to quickly capture the aforementioned deterioration products and prevent the chain reaction. The aim is to

- Phosphite-based stabilizers include tricresyl phosphite, tribenzyl phosphite, trimethyl phosphite, triisopropyl phosphite, trihexyl phosphite, trisnonyclephenyl phosphite, and the like.

Also, the amount of this phosphite stabilizer mixed into the insulating oil varies depending on the use and rating of the capacitor, but it is between 0.1 and
The range was set at 3% (wt%). If the amount is less than 0.1%, the above-mentioned footing effect is small and it cannot be said to be sufficient, and this type of phosphite stabilizer is expensive, so it is desired that the amount is as small as possible. Insulating oils mixed with this phosphite stabilizer include mineral oils, hydrocarbon oils such as alkylnaphthalenes (AN), diallylalkanes (DAA), alkyl diphenyls (ADP), and alkylbenzenes, and flame-retardant tricres oils. Zyl phosphate (T
CP), tri(monoethylphenol) phosphate (
TEP), tri(monoisopropylphenol) phosphate (TPP), cresyl diphenyl phosphate, and other orthophosphate ester oils, as well as mixed oils containing these hydrocarbon oils and orthophosphate ester oils. can be used.

When mixing these to obtain a flame-retardant mixed oil, the mixing ratio of the hydrocarbon oil must be 60% or less by weight. Next, embodiments of this invention will be described.

Figures 1 to 6 show the residual effects of a capacitor in which a capacitor element containing a double-stretched polypropylene film as a thin film derivative is impregnated with an insulating oil containing the above-mentioned phosphite stabilizer when AC voltage is applied at 8-0. The trend of the rate is shown. For comparison, a sample in which no phosphite stabilizer was mixed is also shown with the symbol A in the figure. 1st
In Figures to Figure 6, the solid line is 6.5cm thick, 2nd grade in middle school,
A pair of electrodes made of aluminum foil with a length of 5 mm and two sheets of biaxially stretched polypropylene film with a thickness of 12 mm, medium 22 mm, and a length of 6.5 mm are placed between them. 1
．． It uses a capacitor element wound with a thin sheet of dielectric with a sheet of insulating paper 6.5cm long and 6.5cm long, and the dotted line is 6.5cm thick and 20cm long. , length 5m
a pair of electrodes made of aluminum foil with a thickness of 12r,
A capacitor element is used in which a thin dielectric material consisting of three double-stretched polypropylene films each having a length of 6.5 mm is wound around the capacitor element. The types and mixing ratios (% by weight) of the phosphite stabilizer and insulating oil in FIGS. 1 to 6 are as follows. As is clear from Figures 1 to 6, capacitors impregnated with insulating oil containing phosphite stabilizers did not break down and had a survival rate of 1 after 100 days.
It shows 00%.

However, capacitors impregnated only with insulating oil without mixing phosphite stabilizers (marked with symbol A in each figure)
caused complete destruction in an extremely short period of time. This result is thought to indicate that the deterioration products of organic insulators such as insulating oil and biaxial polypropylene film produced by voltage application were quickly captured by the phosphite stabilizer and the chain reaction was inhibited.

As detailed above, according to the present invention, the insulation performance of a capacitor using a biaxially oriented polypropylene film having various excellent properties as part or all of a thin dielectric material is improved, and moreover, it is possible to improve the insulation performance of a capacitor using a biaxially oriented polypropylene film having various excellent properties. Since only a small amount of the agent is required, the life of this type of capacitor can be extended at a very low cost.

[Brief explanation of the drawing]

Figures 1 to 6 show 80 capacitors implementing this invention.
It is a figure which shows the residual rate when AC voltage is applied at qo. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 Adding 0.1% of a phosphite stabilizer to a capacitor element containing a biaxially oriented polypropylene film as a thin dielectric material
A capacitor characterized by being impregnated with insulating oil containing ~3% by weight.