The biggest advantage of the amorphous alloy iron core distribution transformer is that the no-load loss value is extremely low. Whether or not to ensure the no-load loss value in the end is the core issue to be considered in the entire design process. When amorphous alloy iron core distribution transformer structure is arranged, in addition to considering that the amorphous alloy core itself is not affected by external forces, the characteristics of the amorphous alloy must be accurately and reasonably selected during 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. Generally, a good no-load loss value can be obtained by selecting a magnetic flux density of 1.3 to 1.35T.
(2) The thickness of the single piece of amorphous alloy material is only 0.03mm, so its lamination coefficient can only reach 82% to 86%.
(3) In order to enable users to obtain the benefits of maintenance-free or less maintenance, amorphous alloy iron core distribution transformer are now designed as fully sealed structures.
Structural characteristics of transformer amorphous alloy
The use of amorphous alloy iron core distribution transformer with outstanding magnetic permeability as the core material for manufacturing transformers can ultimately achieve very low loss values. But it has many characteristics that must be guaranteed and considered in design and manufacturing. The main body reflects the following aspects:
(1) The hardness of the amorphous alloy iron core distribution transformer 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 thickness of the single piece of amorphous alloy is extremely thin and the surface of the material is not very flat, so the core filling factor is low.
(3) amorphous alloy iron core distribution transformer are very sensitive to mechanical stress. In structural design, the traditional design scheme with iron core as the main load-bearing structural component must be avoided.
(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 chip, the core of the amorphous alloy iron core distribution transformer is composed of four separate 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 magnetic flux. In the two coil cores of a winding, the third harmonic magnetic flux is exactly opposite in phase, numerically. Equal, so 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. When the voltage waveform of the secondary side is induced, there will be no third harmonic voltage component.
According to the analysis above, the most reasonable structure of a three-phase amorphous alloy distribution transformer is: an iron core, consisting of four separate iron core frames in the same plane, forming a three-phase five-column type which must be annealed and equipped with a crossed iron with rectangular cross-section. The winding has a rectangular cross-section and can be individually wound and formed into a double-layer or multi-layer rectangular layer. The fuel tank of amorphous alloy iron core distribution transformer is a fully sealed and maintenance-free corrugated structure.