Sep. 30, 2020
The biggest advantage of the amorphous alloy iron core distribution transformer is that the no-load loss value is extremely low. Ultimately, whether the no-load loss value can be ensured is the core issue to be considered in the entire design process. When arranging the product structure, in addition to considering that the amorphous alloy core itself is not affected by external forces, it is also necessary to accurately and reasonably select the characteristic parameters of the amorphous alloy in the 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, the magnetic flux density of 1.3 to 1.35T can be selected to obtain a better no-load loss value.
(2) The monolithic thickness of amorphous alloy materials is only 0.03mm, so the lamination coefficient 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.
Structural characteristics of transformer amorphous alloy
The use of amorphous alloys with outstanding magnetic permeability as the core material for manufacturing transformers can ultimately achieve very low loss values. But it has many characteristics, which must be guaranteed and considered in the design and manufacture. It mainly embodies the following aspects:
(1) The hardness of the amorphous alloy sheet material is very high, and it is difficult to cut with conventional tools, so the design should consider reducing the amount of shear.
(2) The amorphous alloy monolithic thickness is extremely thin, and the material surface 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 using the iron core as the main load-bearing structure.
(4) In order to obtain excellent low-loss characteristics, amorphous alloy iron chips must be annealed.
(5) From the electrical performance. In order to reduce the amount of shearing of the iron chip, 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 magnetic circuit frames. In addition to the fundamental magnetic flux, the magnetic flux in each frame also has the third harmonic flux. In the two coiled iron core frames in a winding, the third harmonic flux is exactly opposite in phase and numerically. Equal, therefore, the sum of the third harmonic flux vectors in each group of windings is zero. If the primary side is D connection, there is a loop of third harmonic current, when the induced secondary side voltage waveform, there will be no third harmonic voltage component.
According to the above analysis, the most reasonable structure of the three-phase amorphous alloy distribution transformer is: the iron core is composed of four separate iron core frames in the same plane to form a three-phase five-column type, which must be annealed and equipped with a cross iron yoke The cross-sectional shape of the joint is rectangular. The winding has a rectangular cross-section and can be individually wound into shape, with double or multilayer rectangular layers. The fuel tank is a fully sealed and maintenance-free corrugated structure.
The above information is provided by amorphous alloy power transformer factory.
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