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 106°C/S to form a solid thin strip with a thickness of 0.02-0.03mm. It solidified before it could crystallize. The alloy material is similar to glass in an irregular atomic arrangement, without a crystal structure characterized by metals, and its basic elements are iron (Fe), nickel (Ni), cobalt (Co), silicon (Si), boron (B), carbon (C) etc. Its material has the following advantages:

a) The amorphous alloy material has no crystal structure and is an isotropic soft magnetic material; the magnetization power is small and it has good temperature stability. Since the amorphous alloy is a non-oriented material, direct seaming can be used to make the process of manufacturing the iron core relatively simple;

b) There are no structural defects that hinder the movement of magnetic domains, and the hysteresis loss is smaller than that of silicon steel sheets;

c) The thickness of the strip is extremely thin, only 0.02-0.03mm, which is about 1/10 of the silicon steel sheet.

d) The resistivity is high, about three times that of grain-oriented silicon steel sheets; the eddy current loss of amorphous alloy materials is greatly reduced, so the unit loss is about 20% to 30% of grain-oriented silicon steel sheets;

e) The annealing temperature is low, about 1/2 of the grain-oriented silicon steel sheet;

The no-load performance of the amorphous alloy core is superior. The no-load loss of the transformer made of the amorphous alloy core is 70-80% lower than that of the conventional transformer, and the no-load current is reduced by more than 50%. The energy-saving effect is outstanding. For the purpose of reducing network line loss, both State Grid and China Southern Power Grid have greatly increased the procurement ratio of amorphous alloy transformers since 2012. At present, the proportion of procurement of amorphous alloy distribution transformers has basically reached more than 50%.

Amorphous alloy transformers also have the following disadvantages:

1) The saturation magnetic density is low. The saturation magnetic density of the amorphous alloy core is usually about 1.56T, which is about 20% different from the 1.9T saturation magnetic density of the conventional silicon steel sheet. Therefore, the designed magnetic density of the transformer also needs to be reduced by 20%. The design flux density of crystal alloy oil transformer is usually below 1.35T, and the design flux density of amorphous alloy dry transformer is usually below 1.2T.

2) The total amorphous core strip is sensitive to stress. After the core strip is stressed, the no-load performance is easy to deteriorate. Therefore, special attention should be paid to the structure. The core should be suspended on the support frame and coil, and the whole is only It bears its own gravity. At the same time, special attention should be paid during the assembly process. The iron core cannot be subjected to force, and knocking should be reduced.

3) Magnetostriction is about 10% larger than that of conventional silicon steel sheets, so its noise is more difficult to control, which is also one of the main reasons that limit the widespread promotion of amorphous alloy transformers. The noise of the transformer puts forward higher requirements, which are divided into sensitive areas and non-sensitive areas, and specific sound level requirements are put forward, which requires further reduction of the core design flux density.

4) The amorphous alloy strip is relatively thin, with a thickness of only 0.03mm, so it cannot be made into laminations like conventional silicon steel sheets, but can only be made into coiled cores. Therefore, conventional transformer manufacturers of the core structure cannot process it by themselves, and usually require the overall Outsourcing, corresponding to the rectangular section of the wound core strip, the coil of the amorphous alloy transformer is usually also made into a rectangular structure;

5) The degree of localization is not enough. At present, it is mainly the amorphous alloy strip imported from Hitachi Metals, which is gradually realizing localization. Domestically, Antai Technology and Qingdao Yunlu have amorphous alloy broadband (213mm, 170mm and 142mm). , and its performance is still a certain gap in stability compared with imported strips.

6) The maximum strip length limit, the maximum peripheral strip length of the early amorphous alloy strip is limited by the size of the annealing furnace, and its length is also greatly restricted, but it has been basically solved at present, and an amorphous alloy with a maximum peripheral strip length of 10m can be produced The core frame can be used to manufacture 3150kVA and below amorphous alloy dry change and 10000kVA and below amorphous alloy oil change.

Based on the excellent energy-saving effect of amorphous alloy transformers, coupled with the promotion of national energy conservation and emission reduction and a series of policies, the market share of amorphous alloy transformers is increasing. Moreover, considering the amorphous alloy strip (currently 26.5 yuan /kg) is about twice that of conventional silicon steel sheets (30Q120 or 30Q130), and the gap with copper is relatively small. Considering the quality of grid products and bidding requirements, amorphous alloy transformers usually use copper conductors. Compared with conventional silicon steel sheets, the main cost gaps of amorphous alloy transformers are as follows:

1) Since the wound core structure is adopted, the transformer core type should adopt a three-phase five-column structure, which can reduce the weight of the single-frame core and reduce the difficulty of assembly. The three-phase five-column structure and the three-phase three-column structure have their own advantages and disadvantages in terms of cost At present, most manufacturers adopt three-phase five-column structure.

2) Since the cross-section of the core column is rectangular, in order to maintain the consistency of the insulation distance, the high and low voltage coils are also made into a corresponding rectangular structure.

3) Since the magnetic density of the core design is about 25% lower than that of conventional silicon steel sheet transformers, and its core lamination coefficient is about 0.87, which is much lower than 0.97 of conventional silicon steel sheet transformers, the design cross-sectional area needs to be larger than that of conventional silicon steel sheet transformers. If it is more than 25% larger, the circumference of the high and low voltage coils will also increase accordingly. At the same time, the increase in the length of the high and low voltage coils also needs to be considered. To ensure that the load loss of the coil does not change, the cross-sectional area of the wire needs to be Correspondingly, the amount of copper used in amorphous alloy transformers is about 20% more than that of conventional transformers.