JPH0332908B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to an improvement in oil-immersed capacitors that are widely used for power factor correction, motor drive and operation, and ballasts for lighting equipment. Structure of conventional examples and their problems Oil-immersed capacitors, which are made by wrapping electrode paper with vapor-deposited metal layers on both sides and plastic film as a dielectric layer and impregnating it with insulating oil, have been used in the above-mentioned fields. Widely used. Increasing the potential gradient of such oil-immersed capacitors is advantageous not only in making the plastic film thinner, but also in reducing the consumption of insulating oil and capacitor containers, as well as lowering the price of capacitors. Great effects can be expected in terms of resource conservation. Conventionally, in oil-immersed capacitors using electrode paper, the occurrence of partial discharge has been suppressed due to good impregnation properties, and it also has the self-healing property unique to vapor-deposited metals, so it is possible to use a structure that does not use insulating oil. It is possible to set a higher potential gradient than some dry capacitors or oil-immersed capacitors using metal foil or metallized film. In order to further increase the potential gradient of such an oil-immersed capacitor, it has been proposed to increase the resistance value of the electrode layer on the side where the capacitor is formed to improve self-healing properties. FIG. 1 is a sectional view of a conventional example proposed for this purpose. On both sides of electrode paper 1, 9Ω/
Form a vapor-deposited metal electrode layer 2 using zinc, consisting of a low resistance part of □ below and a high resistance part of 20 to 200Ω/□,
Wrap it with plastic film 3. A non-halogenated insulating oil 4 is filled between the layers, and the electrodes are led out using a metal sprayed part 5 for leading out the electrodes. In the vapor-deposited metal electrode layer 2, a metal sprayed part 5 for leading out the electrode
The reason why the side has low resistance is to reduce the contact resistance between the metal sprayed part 5 for electrode lead-out and the vapor-deposited metal electrode layer 2. However, although this configuration improved self-healing performance, the dielectric loss tangent value increased due to the high resistance on the capacitor formation side, and heat dissipation to the outside through the electrode layer was also suppressed. A problem arose in that it was susceptible to thermal deterioration and thermal destruction under high voltage. Regarding this point, it has been proposed to insert metal foil between the layers and dissipate the heat to the outside through this, but this inevitably increases the volume of the element, and the original purpose of making oil-immersed capacitors smaller and lighter is to reduce the weight. It was not possible to achieve a price reduction. As is clear from the above explanation, oil-immersed capacitors in which the electrode layer on the capacitance formation side has high resistance still have problems such as thermal deterioration and thermal destruction under high temperature and high voltage, and have good self-contained properties. The current situation was that the characteristic of resilience was not being fully utilized. OBJECTS OF THE INVENTION In view of the problems of the oil-immersed capacitors, the present invention
Our goal is to achieve a higher potential gradient by improving the dielectric loss tangent value itself under high temperature and high voltage conditions, thereby making capacitors smaller, lighter, and cheaper. Structure of the Invention As a structure for that purpose, the present invention has a vapor-deposited metal electrode layer made of zinc on both sides, and the resistance value of the vapor-deposited metal electrode layer is 9 on the side of the metal sprayed part for leading out the electrode.
Ω/□ or less, and 20 to 200Ω/ on the capacitance forming part side
A capacitor element is made by winding an electrode paper within the range of □ and a dielectric plastic film in layers, and is impregnated with non-halogenated insulating oil to which one or more types of silane coupling agents are added. Description of Examples Silane coupling agents are those represented by the general formula _YRSiX3 . Here, X is a hydrolyzable group bonded to a Si atom, and representative examples thereof include an alkoxy group, an acyloxy group, and a halogen. Further, Y is an organic functional group, and typical examples thereof include a vinyl group, an amino group, an imino group, a chloro group, an epoxy group, a mercapto group, a peroxy group, and a ureido group. Note that Y is bonded to the Si atom via the organic group R or directly. Such silane coupling agents include, for example, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane,
-glycidoxypropyltrimethoxysilane, γ
-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane,
N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, vinyltris(β-methoxyethoxy)silane, vinyltriethoxysilane, vinyltrichlorosilane, etc., and one or more of these types are added to non-halogenated insulating oil. In this case, the object of the present invention can be achieved. Further, the amount of the silane coupling agent added is desirably about 0.1 to 10% by weight based on the insulating oil. This means that if it is less than 0.1%, it is difficult to see any noticeable effect.
If more than 10% of the silane is mixed in, the insulation resistance value will only decrease slightly and there will be no problem with the properties, but since silane coupling agents are generally expensive, this will cause problems in terms of cost. Examples of the non-halogenated insulating oil used in the present invention include aromatic hydrocarbon insulating oil, aliphatic hydrocarbon insulating oil, and mixtures thereof. Typical examples include phthalate esters, maleate esters, fumarate esters, alkylbenzene oils, and silicone oils. , a remarkable effect can be obtained. Furthermore, it is widely practiced to add up to several percent of epoxy additives to non-halogenated insulating oils as heat stabilizers, voltage stabilizers, or oxidative deterioration inhibitors, but in this case as well, the insulating oil The object of the present invention can be achieved by incorporating a silane coupling agent therein. Further, the plastic film used in the present invention includes, for example, polypropylene film, polyethylene film, polyethylene terephthalate film, polycarbonate film, etc., and remarkable effects can be obtained when one or a mixture of these is used. . As a specific example of the present invention, an oil-immersed capacitor having the structure shown in FIG. The case of a capacitor will be explained below. FIG. 2 shows the relationship between the applied voltage and the dielectric loss tangent value at 100°C. P is a conventional product having the configuration shown in Figure 1 and using only DOP as the insulating oil, and P is an example product of the present invention in which 1% by weight of the silane coupling agent shown in the following table is added to DOP. .

[Table] In the conventional product, the dielectric loss tangent value increases rapidly under high temperature and high voltage, but it can be seen that this is greatly improved in the example product of the present invention. Figure 3 shows the temperature of the capacitor P.
This figure shows the results of a step-up pressure failure test. The voltage was started at 300V, increased by 50V every 24 hours, and the voltage at which the capacitor was destroyed was defined as the withstand voltage. Clearly, in the example products of the present invention, a high withstand voltage far exceeding that of the conventional products is obtained. The above explanation was for the case where the silane coupling agent shown in the table was added, but similar results were obtained when other silane coupling agents were added. Similar results were also obtained when insulating oil other than DOP was used.
Furthermore, similar results were obtained when polyethylene film, polyethylene terephthalate film, polycarbonate film, etc. were used as the dielectric material in addition to PP film. Effects of the Invention According to the present invention, by adding a silane coupling agent to the non-halogenated insulation of an oil-immersed capacitor, an epoch-making capacitor that can withstand high potential gradients far superior to conventional products and is small and lightweight is created. This has an excellent effect that makes it possible to realize the following.

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view of an oil-immersed capacitor, Fig. 2 is a comparative characteristic diagram showing the relationship between applied voltage and dielectric loss tangent value of an oil-immersed capacitor in an embodiment of the present invention and a conventional example, and Fig. 3 is a diagram showing the relationship between the applied voltage and the dielectric loss tangent value in the same step. FIG. 3 is a comparative characteristic diagram showing the results of a pressure-up breakdown test. 1... Electrode paper, 2... Vapor deposited metal electrode layer, 3...
Plastic film, 4...Non-halogenated insulating oil, 5...Metal sprayed part for electrode lead-out.

Claims (1)

[Claims] 1. Having a vapor-deposited metal electrode layer made of zinc on both sides, and the resistance value of the vapor-deposited metal electrode layer is 9 Ω/□ or less on the metal sprayed part side for electrode derivation, and within the range of 20 to 200 Ω/□ on the capacitance forming part side. An oil-immersed capacitor is an oil-immersed capacitor in which a capacitor element made of electrode paper and a plastic film as a dielectric layer is wound around the capacitor element, and is impregnated with non-halogenated insulating oil containing one or more types of silane coupling agents.