CN203760268U - 35kV-level oil-immersed amorphous alloy power transformer - Google Patents

Abstract

The 35kV oil-immersed amorphous alloy power transformer includes a box body, which is equipped with an iron core and a coil. The iron core is an amorphous alloy iron core. The cross-sectional shape of the iron core and the coil is square. The amorphous alloy iron core is three-phase Four-frame five-column coiled core structure, multiple sets of cores are used in parallel between the cores; the upper and lower ends of the iron core are respectively provided with an upper clamp and a lower clamp. The upper and lower ends of the iron core are clamped between the upper clamp and the lower clamp; the coil passes through the middle of the iron core, the iron core is hung on the coil, and the upper and lower ends of the coil are connected to the upper clamp and the lower clamp. Insulation pads are provided between them, a gap is provided between the lower end of the coil and the lower iron yoke of the iron core, and a gap is also provided between the lower end of the coil and the lower clamp. The utility model applies the amorphous alloy material to the 35kV transformer product, which greatly expands the application range of the amorphous alloy material on the transformer.

Description

35kV class oil-immersed amorphous alloy power transformer

technical field

The utility model relates to a power transformer.

Background technique

Amorphous alloy material is a new type of alloy material that came out in the 1970s. It adopts international advanced ultra-quick cooling technology to directly cool liquid metal at a cooling rate of 1×106°C/S to form a solid thin strip with a thickness of 0.02-0.04mm, and obtain atomic Amorphous alloy structure with short-range order and long-range disorder in arrangement and combination. This alloy has many unique performance characteristics, such as excellent magnetism, corrosion resistance, wear resistance, high hardness, high strength, high resistivity, etc. .

Amorphous alloy strip contains 78%~81% iron, 13.5% boron, 3.5%~8% silicon, and also contains trace amounts of metal elements such as nickel and cobalt. Its atomic arrangement is characterized by chaotic and disordered state. The outer surface of the strip is characterized by a thin silver-gray band with a metallic color. At present, there are three types of amorphous alloy strip widths used in the field of power distribution: 142, 170, and 213mm. The main physical properties of it and silicon steel are compared in the table below.

The no-load loss of the transformer is mainly composed of eddy current loss and hysteresis loss. The eddy current loss is proportional to the thickness of the core material and inversely proportional to the resistivity. The hysteresis loss is proportional to the area enclosed by the hysteresis loop. It can be seen from Table 1 that the thickness of the amorphous alloy strip is only 27 μm, which is about 1/11 of the cold-rolled silicon steel sheet, and the resistivity is about 3 times that of the cold-rolled silicon steel sheet. Therefore, the iron core made of amorphous alloy , its eddy current loss is much smaller than that of the core made of cold-rolled silicon steel sheet. In addition, the coercive force of the amorphous alloy is less than 4A/m, which is about 1/7 of that of the cold-rolled silicon steel sheet. The area enclosed by the hysteresis loop of the amorphous alloy is much smaller than that of the cold-rolled silicon steel sheet. The hysteresis loss is also much smaller than that of cold-rolled silicon steel sheets. In summary, the amorphous alloy strip is a material with excellent soft magnetic properties, and the no-load loss of the amorphous alloy transformer is very low, only 25% of that of the S9 type silicon steel transformer.

It is precisely because of the ultra-low no-load loss of the amorphous alloy core transformer that the amorphous alloy core transformer has become the direction of promotion and use in the national grid.

However, compared with silicon steel transformers, amorphous alloy transformers also have shortcomings, such as noise. The noise of the transformer mainly comes from the magnetic excitation of the iron core, which is positively correlated with the magnetostriction coefficient of the iron core material. It can be seen from Table 1 that the saturation magnetostriction coefficient of the amorphous alloy is 30×10 ^-6 , which is a cold-rolled silicon steel Therefore, the noise of amorphous alloy transformers is slightly larger than that of cold-rolled silicon steel sheets. This is also a subject that manufacturers of amorphous alloy transformers need to spend a lot of manpower and material resources on.

Due to the following characteristics of amorphous alloys, it also brings many difficulties to the design and manufacture of amorphous alloy transformer cores: 1. The hardness of amorphous alloys is too high. The biggest problem in manufacturing is how to cut amorphous alloy core pieces. Using conventional cutting tools to process it, the wear rate of the tool will be 1000 times that of cutting silicon steel sheets. 2. The thickness of the amorphous alloy core sheet is extremely thin, about 0.027mm thick, which is almost less than one-tenth of the silicon steel sheet. The surface of the material is not very flat, and the iron core is made of it, and the filling factor is low, only 80%. 3. Amorphous alloys are very sensitive to mechanical stress and are easily broken after annealing.

Now there are professional manufacturers of amorphous alloy cores, which specially provide formed amorphous alloy transformer cores for transformer factories, which solves the problem of manufacturing amorphous alloy cores. Transformer manufacturers can order amorphous alloys of various sizes and specifications according to their needs. Transformer core.

Due to some restrictions on the specifications and characteristics of amorphous alloy materials, amorphous alloy cores are currently only used in some small-capacity transformers, especially in distribution transformers, which tend to be popularized in large areas. It is more difficult to apply to power transformers of 35kV and above, and there are many technical problems to be solved.

Utility model content

The purpose of the utility model is to provide a 35kV oil-immersed amorphous alloy power transformer to reduce the loss of the transformer.

The technical scheme of the utility model is:

The 35kV oil-immersed amorphous alloy power transformer includes a box body, which is equipped with an iron core and a coil. The iron core is an amorphous alloy iron core. The cross-sectional shape of the iron core and the coil is square, and the amorphous alloy iron core is three-phase. Four-frame five-column wound core structure, multiple sets of iron cores are used in parallel between the iron cores; the upper and lower ends of the iron core are respectively provided with upper clamps and lower clamps, and the upper clamps and lower clamps are in the shape of a few characters. The upper and lower ends of the iron core are clamped between the upper clamp and the lower clamp; the coil passes through the middle of the iron core, the iron core is hung on the coil, and the upper and lower ends of the coil and the upper clamp and the lower clamp are Insulation pads are provided between them, a gap is provided between the lower end of the coil and the lower iron yoke of the iron core, and a gap is also provided between the lower end of the coil and the lower clamp.

The coil includes a high-voltage coil and a low-voltage coil. There is a main empty space between the high-voltage coil and the low-voltage coil. A square corner ring is provided between the upper and lower ends of the high-voltage coil and the insulating pads on the corresponding side.

The utility model applies the amorphous alloy material to the 35kV transformer product, which greatly expands the application range of the amorphous alloy material on the transformer, and due to the ultra-low no-load loss of the amorphous alloy material, the application of the utility model will cause unfavorable The estimated economic and social benefits can greatly reduce the power consumption of the current transformer itself.

Description of drawings

Fig. 1 is the structural representation of the iron core of the utility model;

Fig. 2 is a structural schematic diagram of the iron core fastening structure of the present utility model;

Fig. 3 is a schematic diagram of the supporting structure of the iron core of the present invention;

Fig. 4 is the B-B sectional view of Fig. 3;

Fig. 5 is a schematic diagram of the structure when the square corner ring structure is adopted on the main insulation structure of the transformer;

Fig. 6 is a schematic diagram of the position of the square corner ring;

Fig. 7 is a structural schematic diagram of a transformer coil mould;

Fig. 8 is a cross-sectional view along line A-A of Fig. 7 .

Detailed ways

As shown in Fig. 1, the 35kV oil-immersed transformer of the present invention includes a box body 10, and the iron core 1 in the box body 10 adopts an amorphous alloy iron core. The no-load loss of the utility model is only 20-30% of that of ordinary transformer products, so it can greatly reduce the loss of the transformer, has a good energy-saving effect, and has immeasurable economic and social benefits.

Generally, the common transformer core is a three-phase three-column type. Due to the limitation of the production and processing difficulty of the amorphous alloy material, the cross-sectional shape of the amorphous alloy core 1 of the utility model is all square. The amorphous alloy core 1 is a three-phase, four-frame, five-column wound core structure, which can meet the needs of processing amorphous alloy materials.

The current small-capacity amorphous alloy iron core transformer is generally a single group. The utility model is to increase the cross section of the iron core. However, due to the limitation of the bandwidth of the amorphous alloy material, the iron core 1 adopts the form of multiple sets of iron cores connected in parallel. The cores are insulated from each other and grounded separately.

The current design method of the transformer is suitable for a structure in which both the iron core and the coil are circular.

However, the iron core 1 and the coil 2 of the transformer of the utility model are both square, and the existing various design methods are no longer applicable. The utility model adopts the design method of deriving an equivalent circle, which is suitable for a square structure and greatly simplifies the design. program. Can meet the requirements.

As shown in Fig. 2, the core clamps of the existing transformers are generally channel steel or plate structure, and the high and low voltage clamps are separated. Since the amorphous alloy material is relatively sensitive to stress, the iron core 1 cannot be stressed, and the transformer needs to adopt a new iron core fastening structure to avoid the iron core being stressed. The upper clamping part 3 and the lower clamping part 4 of the iron core 1 adopt a zigzag structure, and the iron core 1 is put into the upper clamping part 3 and the lower clamping part 4, so that the iron core 1 can be prevented from being subjected to a large clamping force.

The upper clamping part 3 and the lower clamping part 4 (high and low voltage clamping parts) are integral structures, which can prevent the iron core 1 from being subjected to a large clamping force and meet the requirement that the amorphous alloy iron core cannot be subjected to force.

As shown in Figures 3 and 4, all existing transformers have a structure with an iron core as the skeleton, and the coil is fastened by the iron core skeleton.

Since the iron core of the amorphous alloy iron core transformer is not allowed to be subjected to internal stress, the support of the iron core is a difficult problem. After research and discussion, the utility model hangs the iron core 1 on the coil 2, which can reduce the force on the iron core 1 as much as possible.

Between the upper clip 3 , the lower clip 4 and the two ends of the coil 2 are two insulating pads 5 . The upper clamping part 3 and the lower clamping part 4 of the utility model clamp the coil 2 through the insulating spacer 5 by screw rods and put them on the foundation feet. In this way, the upper and lower clamping parts, the coil 2 and the foundation feet have been fixed as a whole, and they As a skeleton of the transformer body, the iron core 1 hangs upside down on the coil 2, and there is a certain gap between the lower iron yoke of the iron core 1 and the coil 2, and between the coil 2 and the lower clamp 4, which can ensure that the iron core 1 only bears its own weight. Instead of being subjected to additional stress, it meets the requirement that the amorphous alloy core cannot be stressed.

As shown in Figures 5 and 6, due to the high voltage level of the transformer, the utility model adopts a square corner ring structure on the main insulation structure of the transformer. The upper and lower parts of the coil 2 are insulating pads 5, and the coil 2 includes a high-voltage coil 2-1. and the low-voltage coil 2-2, the main air passage 7 between the high-voltage coil 2-1 and the low-voltage coil 2-2, and between the upper and lower ends of the high-voltage coil 2-1 and the insulating pads 5 on the corresponding side There is a square corner ring 6, the square corner ring 6 is the existing equipment, the use of the square corner ring 6 improves the insulation performance, reduces the distance of the main empty channel 7, reduces the cost of the transformer, and improves the performance of the transformer.

As shown in Figures 7 and 8, the coil 2 is made of a transformer coil mould, the heart of the transformer coil moiety is two circular arc tire hearts 8, and the two ends of the arc tire heart 8 are baffles 9. With this structure, the The processing and installation of the coil mold become simple and convenient, which meets the needs of square coil production.

Claims (2)

The 1.35kV oil-immersed amorphous alloy power transformer includes a box body, and the box body is equipped with an iron core and a coil. The alloy iron core is a three-phase, four-frame, five-column wound core structure, and multiple sets of iron cores are connected in parallel between the iron cores; the upper and lower ends of the iron core are respectively equipped with an upper clamp and a lower clamp. Glyph structure, the upper and lower ends of the iron core are clamped between the upper and lower clamps; the coil passes through the middle of the iron core, the iron core is hung on the coil, the upper and lower ends of the coil and the upper clamp Insulation pads are provided between the lower clips, a gap is provided between the lower end of the coil and the lower iron yoke of the iron core, and a gap is also provided between the lower end of the coil and the lower clip. 2. The 35kV oil-immersed amorphous alloy power transformer according to claim 1, characterized in that: the coil includes a high-voltage coil and a low-voltage coil, the main space between the high-voltage coil and the low-voltage coil, and the upper and lower ends of the high-voltage coil A square corner ring is respectively arranged between the insulating pads on the corresponding side.