Amorphous Alloy Transformer

Amorphous Metal Transformer (AmorphousMetalTransformer) is a low loss, high energy efficiency power transformer. This type of transformer uses iron-based amorphous metal as the iron core. Since this material does not have a long-range ordered structure, its magnetization and demagnetization are easier than ordinary magnetic materials. Therefore, the iron loss (that is, no-load loss) of the amorphous alloy transformer is 70-80% lower than that of the traditional transformer that generally uses silicon steel as the core. Due to the reduction in losses, the demand for power generation is also reduced, and the emission of greenhouse gases such as carbon dioxide is correspondingly reduced. Based on energy supply and environmental protection factors, amorphous alloy transformers are widely used in large developing countries such as China and India. Based on the current electricity consumption of China and India, if amorphous alloy transformers are fully used in the distribution network, about 25-30TWh of power generation can be saved each year, and 20 to 30 million tons of carbon dioxide emissions can be reduced.



1. Design of amorphous alloy transformer

Amorphous Alloy Transformer

The biggest advantage of the amorphous alloy iron core distribution transformer is that the no-load loss value is extremely low. Whether the no-load loss value can be guaranteed in the end is the core issue to be considered in the entire design process. When laying out the product structure, in addition to considering that the amorphous alloy iron core itself is not affected by external forces, it is also necessary to accurately and reasonably select the characteristic parameters of the amorphous alloy during calculation. In addition to this design idea, the following three requirements must be followed:



(1) Due to the low saturation magnetic density of amorphous alloy materials, the rated magnetic flux density should not be selected too high during product design. Usually, a better no-load loss value can be obtained by selecting a magnetic flux density of 1.3-1.35T.



(2) The thickness of a single piece of amorphous alloy material is only 0.03mm, so its lamination factor can only reach 82% to 86%.



(3) In order to enable users to obtain the benefits of maintenance-free or less maintenance, the products of amorphous alloy distribution transformers are now designed as fully sealed structures.



Second, the structural characteristics of transformer amorphous alloy



Using the amorphous alloy with outstanding magnetic permeability as the iron core material of the transformer can finally obtain a very low loss value. But it has many characteristics, which must be guaranteed and considered in design and manufacture. It mainly reflects the following aspects:



(1) The hardness of the amorphous alloy sheet material is very high, and it is difficult to cut it with conventional tools, so the design should consider reducing the amount of shearing.



(2) (2) The monolithic thickness of the amorphous alloy is extremely thin, and the surface of the material is not very flat, so the core filling factor is low.



(3) Amorphous alloys are very sensitive to mechanical stress. When designing the structure, it is necessary to avoid the traditional design scheme of using the iron core as the main load-bearing structural member.



(4) In order to obtain excellent low-loss characteristics, the amorphous alloy iron chip must be annealed.



(5) From the electrical performance. In order to reduce the amount of shearing of the iron chips, the iron core of the whole product is composed of four separate iron core frames side by side, and each phase winding is sleeved on two independent frames of the magnetic circuit. In addition to the fundamental magnetic flux, the magnetic flux in each frame also has the third harmonic flux. In the two wound iron core frames in one winding, the third harmonic flux is exactly opposite in phase and numerically. Equal, therefore, the third harmonic flux vector sum in each set of windings is zero. If the primary side is D connection, there is a loop of the third harmonic current, and there will be no component of the third harmonic voltage on the induced voltage waveform of the secondary side.



According to the above analysis, the reasonable structure of the three-phase amorphous alloy distribution transformer is: iron core, composed of four separate iron core frames in the same plane to form a three-phase five-column type, which must be annealed and has a cross iron yoke connection Seam, the cross-sectional shape is rectangular. The winding has a rectangular cross-section and can be individually wound into a double-layer or multi-layer rectangular layer. The oil tank is a fully sealed and maintenance-free corrugated structure.



3. Performance of amorphous alloy transformer



The new S9 type distribution transformer widely used at present, the magnetic material used in the iron core is usually 30Z140 high magnetic permeability cold-rolled silicon steel sheet, its saturation magnetic density is higher than that of amorphous alloy, and the magnetic flux density selected in product design is usually Between 1.65 and 1.75T. This is one of the main reasons why the no-load loss of the amorphous alloy core distribution transformer is lower than that of the new S9 distribution transformer.



Fourth, the development prospect of amorphous alloy transformer



If it can completely replace the new S9 series distribution transformers, if the annual demand for 10kV distribution transformers is calculated as 50 million kVA, then more than 10 billion kW·h of electricity can be saved a year. At the same time, it can also bring good environmental protection benefits of less power plants and less greenhouse gas emissions to the atmosphere, which will greatly reduce direct pollution to the environment and make it a new generation of veritable green products. In short, in the development and transformation of urban and rural power grid systems, if the country can widely promote the use of three-phase amorphous core distribution transformer products, it will eventually obtain benefits in both energy saving and environmental protection.