JPS5860518A - 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] The present invention relates to improvements in oil-filled capacitors.

As shown in Figure 1, the structure of a conventional oil-filled capacitor consists of a plurality of capacitor elements (l) made up of a dielectric using insulating paper and an electrode foil layered together and wound together in a roll shape, with press ports at both ends. After applying a clamping plate 2 consisting of a material such as the like, it is tightened with a clamping band 3 to obtain the rated capacitance, and after being placed in a container 4, it is sealed by vacuum drying and binding oil impregnation treatment. .

By the way, recently, glass film has been used instead of insulating paper for the dielectric material of oil-filled capacitors. Using a plastic film as the dielectric in this way is advantageous because its own water content is significantly eliminated; however, if the capacitor element l is tightened with the tightening band 3 as shown in Fig. 1, the dielectric will be It becomes difficult for water on the surface to be released. Further, when impregnating with insulating oil, there is a problem that infiltration of the insulating oil into the dielectric layer is inhibited. Therefore, the insulation treatment takes a considerable amount of time and increases the number of man-hours, and there has been a demand for a change in this process.

An object of the present invention is to provide an oil-filled capacitor that can be easily and completely dried and impregnated with insulating oil even if a glass film is used as the dielectric.

The present invention provides a metal piece with a shape memory effect between a container and a capacitor element housed therein, and after impregnating this metal piece with insulating oil, heats the metal piece to a temperature higher than the transformation temperature. It is characterized in that the element is configured to be tightened to a predetermined size.

The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 2 1, a plurality of capacitor elements 1 are gathered together, and clamping plates 2 made of an insulating material are held at both ends of the capacitor elements 1 in the gathering direction. The capacitor element assembly 4 is housed in a capacitor element assembly, and 5 is a metal piece having a shape memory effect, which is interposed at the threshold between the clamping plate 2 and the container 4, respectively. The metal piece 5 is made of titanium, such as Nitinol (trade name).
It is made of a nickel alloy and is heated to a temperature of 550°C or higher and processed into a 4-shape as shown in Figure 3, then returned to room temperature and plastic-worked into a U-shape, which is then applied to the inner wall of the container 4. It is something that This metal piece S is heated to a transformation temperature of 135°C*10°C or higher after vacuum drying the capacitor element assembly 1m housed in the container and impregnating it with insulating oil. Tighten the capacitor element assembly 1mm by the specified distance 5 times with the force of trying to return it (second
Figure baml).

Note that the stress when the metal piece 5 returns to its shape is 601-1 or more, so a sufficient tightening force can be obtained for the capacitor element.
Further, although not shown, by providing a stopper in the container 4 for restraining the movement of the clamping plate 2 at an appropriate position, the clamping dimension can be kept within a required value.

According to the above configuration, vacuum drying and insulating oil impregnation treatment can be performed without applying clamping pressure to the capacitor element, so water can be removed from the dielectric surface during drying and insulating oil can be impregnated into the dielectric layer. Impregnation can be carried out quickly and completely.

As a result of measuring the corona start voltage of the 200KV oil-filled capacitor manufactured in this way and the conventional type oil-filled capacitor of the same rating, the results are as shown in Figure 4. The voltage characteristics were found to be stable with little variation in voltage values, and the average value of the corona onset voltage to be as high as 5 to 10%.

As described above, according to the present invention, it is possible to provide an oil-immersed capacitor that has a simple structure, allows drying and insulating oil impregnation treatments to be easily and completely performed, and has high reliability and excellent insulating properties.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional oil-filled capacitor, Figure 2 (a)
and (b) are cross-sectional views showing the state before and after tightening of the capacitor element of the oil-filled capacitor according to the present invention,
FIG. 3 is a perspective view of a metal piece for tightening a capacitor element, and FIG. 4 is a corona start voltage characteristic diagram of the same oil-filled capacitor. l...Capacitor element 1 person...Capacitor element assembly 2...Tightening plate 4...Container 5...
Metal Piece Agent Patent Attorney Mr. Inoue Figure 1 Figure 2

Claims (1)

[Claims] A container, a capacitor element assembly in which several capacitor elements are assembled and housed in the container with clamping plates held at both ends in the assembly direction so that no clamping pressure is applied, and a clamping of this capacitor element assembly. It is interposed between the attached plate and the container and changes after being impregnated with loquat oil! An oil-filled capacitor consisting of a metal piece that has a shape memory effect that tightens the capacitor element assembly to a predetermined size by changing its shape when heated to a temperature higher than