JPH03250714A - Foil wound transformer - 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] [Objective of the Invention] (Industrial Application Field) The present invention has a foil-like winding made of a metal sheet and an insulating sheet wound in layers, and a cooling duct is built into the winding. This relates to foil-wound transformers.

(Prior Art) As is well known, transformer insulation can be roughly divided into dry type and wet type. The typical wet type transformer is an oil-immersed transformer, but its use in underground substations of buildings is decreasing because of the risk of explosion due to oil leakage and fire. On the other hand, dry type transformers include face-treated transformers and molded transformers, but face-treated transformers have the disadvantage that their insulation properties deteriorate due to dust and dirt, so molded transformers are currently the mainstream. Here, a molded transformer is one in which the windings of the transformer are placed in a mold and impregnated with synthetic resin under reduced pressure. Therefore, it has a very good appearance and has the advantage of being easy to maintain, as it can be washed with water in extreme cases even against dust and dirt from the outside.

(Problem to be Solved by the Invention) However, since all of the windings of a molded transformer are wrapped in impregnated resin, the cooling characteristics thereof are generally several times lower than those of the insulating oil type. In recent years, as the demand for higher voltage, larger capacity, and non-flammable transformers has increased, it has become important to find ways to improve cooling capacity and provide windings with high dielectric strength. .

As the sleep pressure and capacity increase, the amount of heat generated during operation of the transformer also increases, exceeding the allowable heat resistance temperature of the insulating material.
This causes insulation deterioration and reduces its reliability. Unlike oil-immersed transformers, molded transformers do not have a cooling function by circulating an insulating medium, so the inside of the windings cannot be forcibly cooled with liquid or air, and the amount of heat generated by winding losses is reduced. It was not suitable for large-capacity transformers.

Another disadvantage of molded transformers is that they require a mold. That is, the impregnated resin has the advantage that it has a very good appearance because it can be made into a quality product that matches the shape of the mold by using a mold, but on the other hand, the manufacturing process is entirely determined by the mold. Therefore, in the case of mass production, a large number of the same molds must be prepared, and in the case of multi-product production, various types of molds must be prepared. The mold, of course, depends on the capacity of the transformer, but it must be strong enough to be transported and moved even when the transformer windings and impregnated resin are impregnated, which makes it large and heavy. In addition, molds are often divided into two or three or more parts, but the appearance of the windings impregnated with the impregnated resin of the transformer is determined by the degree of finish on the inside of the mold. Finishing the inner surface of the mold requires considerable precision. Furthermore, even if the impregnating resin is impregnated, extreme care must be taken to ensure that it does not leak from the joints of the molds. Therefore, the production cost of the mold becomes high, making the molded transformer expensive.

An object of the present invention is to solve the problems of the prior art as described above, particularly to improve the cooling efficiency and insulation reliability of the foil winding, and to provide a foil-wound transformer with excellent mechanical strength. .

[Structure of the Invention] (Means for Solving the Problems) The foil-wound transformer of the present invention includes a metal sheet and an insulating sheet that are layered and wound, a cooling duct that extends in the axial direction is wound in the middle of the winding, and the The shaped winding is housed in an insulating container together with a cooling duct, and after being cast and impregnated with an insulating material, it is housed in a tank together with an insulating medium.

(Function) With the structure described above, cooling of the winding is performed by heat transfer between the cooling duct and the winding by flowing refrigerant into the cooling duct, so the cooling characteristics are improved. . Furthermore, since the entire winding is cast with an insulator, it has excellent insulation properties, and by using a glue-like insulator, heat cycles due to operation are repeated.
Cracks do not occur even if the materials expand and contract due to differences in their thermal expansion coefficients. Furthermore, a mold for molding the insulator becomes unnecessary.

(Example) An example of the present invention will be described below with reference to the drawings. The figure is a sectional view showing a foil-wound transformer according to an embodiment of the present invention. In the figure, a main landing gear core IK metal sheet 2 and an insulating sheet 3 are wound in an overlapping manner to form a low-voltage winding 4 and a high-voltage winding 5.
A hollow cooling duct 6 is wound within these windings 4°5. A condensable or non-condensable refrigerant is sealed in a thin gap in the hollow part of the cooling duct 6.
The refrigerant is insulated by a pump (not shown)! The liquid is guided from the liquid collecting pipe 8 to an external cooling system (not shown) through the id 7, and is configured to circulate within the cooling duct 6 to cool the windings. Such a foil winding is housed in an insulating container 9, and the inside of this insulating container 9 is cast with an insulator 10 made of a solid insulator such as epoxy resin or a glue-like insulator such as silicon dull. The cast insulating container 9 is stored in a tank 12 together with an insulating medium 1. The insulating medium 1 may be an insulating liquid such as insulating oil or silicone oil, or an insulating gas such as SF6 gas. With this configuration, the foil winding 5 is insulated by the solid or semi-solid insulating material 10 such as glue, which has excellent insulating performance, and the insulation reliability is greatly improved. In addition, since the foil winding 4°5 is cooled by the cooling duct 6 built into the sheet 23 and the heat conduction between the sheets 2 and 3, the cooling efficiency is very high. Since it is cooled regardless of the insulating material 10 of
In addition, there is no need to separately prepare a special mold or container for casting. As a result, casting is easy and a container for casting is not required, improving work efficiency.Furthermore, an inexpensive transformer can be obtained without the need for an expensive mold.In addition, the container 9
The transformer can be made non-flammable by housing it in the tank 12 together with the non-flammable insulating medium 11. The insulating medium 1) can be either an insulating gas or a liquid, and either can be used depending on the purpose of the transformer. Furthermore, by filling the insulator with a glue-like insulator such as silicon del or a substance such as insulating rubber, cracks will not occur in the insulator due to differences in thermal expansion even if the heat cycle due to the operation of the transformer is repeated. suppressed, and
It has a significant effect on suppressing vibrations, mechanical movements, and even noise during operation, increasing insulation reliability.

Note that when casting a solid or glue-like insulator on the foil winding 4.5 in the insulating container 9, an insulating/arm-shaped insulator for flowing the refrigerant into the cooling duct 6 must be attached in advance and then cast. Alternatively, the cooling duct 6 and the insulation Δve 7
It is also possible to cast the connection port so that it comes out of the cast insulator, and to connect it to the insulation/die differential after casting. Furthermore, if the insulating material 10 is taken out only from above the insulating/die-def Vi insulating container 9, the insulating material 10 can be cast efficiently. In addition, without being limited to this configuration, the cooling duct 6 and the insulation container 9 can be connected to the lower part of the insulation container 9. It may be configured such that a connection portion for the ide 7 is provided and the insulating/mother ide 7 is pulled out from below.

[Effects of the Invention] As described above, according to the present invention, a foil winding is formed in which a metal sheet and an insulating sheet are overlapped and wound, and a plurality of cooling ducts extending in the axial direction are wound in the middle of the winding. The insulating container is housed in an insulating container, and the insulating container is filled with a solid or semi-solid insulator such as a glue-like insulator, and then the insulating container is stored in a tank together with an insulating medium. , the cooling efficiency of the windings is increased, and the insulation reliability of the windings is also increased.If a glue-like insulator is used in the front, there is no worry of cracks, etc., and it also absorbs the electromagnetic vibrations of the equipment, making it possible to improve the insulation reliability of the windings. It is possible to obtain a foil-wound transformer with low noise caused by vibration and high mechanical reliability.

[Brief explanation of drawings]

The figure is a sectional view showing one embodiment of the present invention. 1... Iron core, 2... Metal sheet, 3... Insulating sheet, 4... Low voltage winding, 5-... High voltage winding, 6... Cooling duct, 7... Insulation/I Eve, 8...Liquid collection pipe, 9
... Insulating container, 10... Insulator, 11... Insulating medium, 12... Tank.

Claims (1)

[Claims] A foil-wound transformer is equipped with a foil-shaped winding in which a metal sheet and an insulating sheet are overlapped and wound around the legs of an iron core, and a plurality of cooling ducts extending in the axial direction are wound between the sheets. A foil-wound transformer characterized in that it is housed in an insulating container, cast-impregnated with a solid or glue-like insulator, and then housed in a tank together with an insulating medium.