JPH065439A - Winding for stationary induction apparatus - Google Patents

Abstract

PURPOSE:To improve flame retardance and reliability of a winding for a stationary induction apparatus by providing means for always holding gel-like silicone in a pressurized state and absorbing its expansion. CONSTITUTION:A conductor 1 is wound on an inner peripheral insulation cylinder 2 through a radial spacer 3 and an axial spacer 4 to form a winding. A temporary bottom plate and a temporary outer peripheral cylinder are respectively mounted on a lower part and a periphery of the winding, gel-like silicone 5 of a low viscosity state before gelling is filled, and gelatinized. Thereafter, the bottom plate and the peripheral cylinder are removed, and a bottom plate 6, an outer peripheral plate 7 and a cover 8 having sizes larger than those of the bottom plate and the peripheral cylinder are mounted airtightly. Then, inert gas 9 is sealed in a space of this sealed case under a predetermined pressure. Thus, a winding for a stationary induction apparatus filled with the gel-like silicone can be obtained without introducing insulation malfunction due to a variation in a load even when it is applied to a large capacity and a high voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a winding wire for a static induction device such as a transformer, and more particularly to a winding wire for a static induction device which is flame retardant, lightweight and compact.

[0002]

2. Description of the Related Art In recent years, power equipment has been increasingly installed in urban areas in response to the expansion of power demand in the urban areas. Of this type of power equipment, equipment installed in buildings or underground malls, especially large equipment such as transformers, is
Safety and environmental friendliness are required.

In urban areas, the price of land is high, and the equipment is installed in places where there are severe restrictions on transportation.
Miniaturization is a top priority issue. Therefore, various incombustibility,
Research is being conducted on the application of flame-retardant insulating media to transformers.

Under such a background, conventionally, a mold transformer cast with an epoxy resin has been widely used. However, defects such as cracks and voids are caused by heat shrinkage caused by a curing reaction at the time of casting. Since it is easy to form, and in some cases corona discharge may occur under high voltage and eventually cause dielectric breakdown, 33 kV is said to be the practical limit at present.

On the other hand, for flame-retardant oils such as silicone oil, highly reliable insulating properties can be easily obtained by vacuum lubrication or the like, but since it has a flash point because it is a liquid, it is more disaster-proof than a molded transformer. There is no choice but to say that it is inferior.

Therefore, liquid and solid as a disaster prevention type transformer having both excellent flame retardancy of a solid insulation device such as a mold transformer and excellent insulation property of a liquid insulation device such as a silicone oil-filled transformer. The one using a gel-like insulator having an intermediate property of is expected.

As a proposal regarding such a transformer,
Japanese Laid-Open Patent Application No. 56-56 for relatively high voltage and small capacity
There are those described in Japanese Patent No. 118313 and Japanese Patent Laid-Open No. 3-250714.

That is, the high-voltage winding and the low-voltage winding are arranged on the legs of the iron core, housed in a case, and then filled with gel-like silicone. Usually, by filling in a low-viscosity state before gelation, void defects do not occur even if the object to be filled has a complicated shape. In addition, there is no heat generation due to the gelation reaction, and since it is extremely flexible, cracks do not occur.

[0009]

However, when such a structure is used for a large capacity, high voltage power transformer or the like, the following problems may occur.

1) Since silicone gel has a high gas permeability, when the winding temperature suddenly rises due to a change in load or the like, a void is generated due to the absorbed air.
It causes insulation failure.

2) Since the silicone gel has a large coefficient of thermal expansion (5-10% volume expansion at 100 ° C. increase), the volume of the gel filled in each part increases when the winding temperature rises due to an increase in ambient temperature or load. It expands and partially peels off or forms voids from the winding conductor, resulting in insulation failure.

The present invention has been made in view of the above circumstances, and even when applied to a large capacity and a high voltage, a transformer filled with a gel-like silicone does not cause insulation failure due to load fluctuation and the like. To provide a winding for a static induction device.

[0013]

A winding for a static induction device according to the present invention has a case in which the winding is housed and is filled with gel-like silicone, and at least a part of the case is filled with the gel-like silicone. It is characterized in that a means for absorbing a swelling of the gel-like silicone is provided while maintaining a constantly pressurized state.

In this case, at least a part of the case may be filled with an inert gas or foamed foam to constitute means for keeping the gel-like silicone under a constant pressure and absorbing the expansion of the gel-like silicone. . Alternatively, a gas expansion chamber communicating with the inside of the case may be provided, and the inside of the gas expansion chamber may be filled with an inert gas for keeping the gelled silicone in a pressurized state at all times.

[0015]

According to the winding for a static induction device of the present invention,

1) The gel-like silicone is always kept in a pressurized state even when voids are generated by the air absorbed in the gel-like silicone when the winding temperature suddenly rises due to load fluctuation or the like. Since the structure is adopted, the voids cannot grow to a size that poses a problem in terms of insulation, and insulation failure does not occur.

2) When the temperature of the winding increases due to an increase in the ambient temperature or the load, even when the gel-like silicone filled in each part expands in volume, the winding conductor is always kept in a pressurized state. Without peeling or voids from the
Does not cause insulation failure.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the winding for a static induction device of the present invention will be described below with reference to FIG. On the inner insulation cylinder 2,
The conductor 1 is wound around the radial spacer 3 and the axial spacer 4 to form a winding. Attach a temporary bottom plate and a temporary peripheral cylinder (not shown) to the lower part and the periphery of this winding,
Fill with low viscosity gelled silicone 5 before gelling,
Harden (gel). After that, the temporary bottom plate and the temporary outer peripheral cylinder are removed, and the bottom plate 6, the outer peripheral cylinder 7, and the cover 8 which are larger in size than the temporary bottom plate and the temporary outer peripheral cylinder are airtightly attached.

After the winding is housed in the airtight case and filled with the gel-like silicone in this way, an inert gas 9 such as nitrogen gas is sealed at a predetermined pressure in the space of the airtight case. To form a winding for static induction equipment.

With such a structure, the inside of the airtight case is always kept in a pressurized state by the inert gas 9. Therefore, even if the winding temperature suddenly rises due to load fluctuation or the like, the gel silicone 5 The possibility that voids will be generated due to the air or gas absorbed inside will be reduced. Also, as the winding temperature rises, the pressure inside the airtight case also rises, so even if a void occurs, the void cannot grow to a size that poses an insulation problem, resulting in insulation failure. There is no.

Further, even when the gel-like silicone 5 filled in each part expands in volume when the winding temperature rises due to the ambient temperature or the load increase, the gel-like silicone 5 is applied with a force so as to adhere to the conductor 1. Therefore, peeling from the winding conductor 1 and voids do not occur, and insulation failure does not occur.

The airtight case may be connected to an external gas expansion chamber (not shown) by a pipe or the like. At least the inside of the gas expansion chamber may be filled with an inert gas to keep the gelled silicone in a pressurized state at all times. For example, it becomes easier to suppress the change in internal pressure with respect to the change in winding temperature within a predetermined range while minimizing the volume of the winding portion.

Further, as shown in FIG. 2, if the foamed foam 10 such as foamed silicone which cures while foaming in the two-liquid mixing is filled around the gel-like silicone 5, the same effect as the above-mentioned embodiment can be obtained. In addition, the case does not need to be airtight, which facilitates the manufacture and eliminates the need for monitoring the internal pressure.

[0024]

As is apparent from the above description, according to the present invention, since the means for keeping the gelled silicone in a pressurized state at all times and absorbing the expansion thereof is provided, it is applied to a large capacity and a high voltage. Also in this case, it is possible to provide a flame-retardant and highly reliable winding for a static induction device that does not cause insulation failure due to load fluctuations and the like.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a winding for a static induction device according to the present invention with a partial cross section thereof.

FIG. 2 is a perspective view showing a partial cross-section of another embodiment of the present invention.

[Explanation of symbols]

1 is a conductor, 2 is an inner peripheral insulating cylinder, 3 is a radial spacer, 4
Is an axial spacer, 5 is a gel silicone, 6 is a bottom plate,
Reference numeral 7 indicates a peripheral cylinder, 8 indicates a cover, 9 indicates an inert gas, and 10 indicates foamed foam.

Claims (3)

[Claims] 1. A case in which windings are housed and gelled silicone is filled in a case, wherein at least a part of the case is kept under pressure, and the gelled silicone expands. A winding for a static induction device, characterized by being provided with a means for absorbing. 2. A means for absorbing an expansion of the gel-like silicone while keeping the gel-like silicone under a constant pressure by filling at least a part of the case with an inert gas or foamed foam. The winding for a static induction device according to claim 1. 3. A case in which a winding is housed and gelled silicone is filled, a gas expansion chamber communicating with the case is provided, and the gelled silicone is constantly added to the inside of the gas expansion chamber. A winding for a static induction device, characterized by being filled with an inert gas which is kept under pressure.