1) adopt magnetic flux leakage (MFL) calculation, take effective measures to reduce the stray loss, at the same time effectively prevent local overheating and reduce the temperature rise of winding hot spots. 2) reasonable selection of coil conductor, reduce the winding eddy current loss, stray loss and other additional losses. 3) optimize the transposition between parallel wires to make the cross-link flux even and reduce the circulation loss caused by magnetic leakage. 4) new magnetic shielding structure is adopted to reduce the stray loss of structural parts and prevent local overheating. 5) grooving is carried out on the small grade pieces of the iron core to reduce the loss of the structural parts of the iron core and prevent local overheating.

1) the short circuit mechanical force is calculated by dynamic analysis method. 2) self-viscous transposition conductor is adopted for low pressure, which effectively increases the short-circuit resistance. 3) the windings are wound by vertical winding machine or horizontal winding machine with tensioning device, lined with cardboard tube. 4) wire transposition adopts hydraulic transposition tool. 5) the body adopts constant pressure drying and integral assembly, and the integral assembly adopts hot suit.

1) carry out analytical calculation on the electric field to improve the area where the electric field is concentrated. 2) through the use of special binder, vacuum oil injection after the transformer is fully assembled, it can effectively prevent the formation of bubbles in the insulation parts and the transformer, thus reducing the local discharge. 3) the iron core, coil winding, machine body assembly, general assembly and test are all carried out in the fully air-conditioned, fully enclosed and dust-free purification workshop to effectively control the foreign body into the machine body. Meanwhile, the connection of the lead wire is carried out by pressing connection (different from common welding) to reduce the local discharge.

1) select high-quality core materials, select appropriate magnetic flux density and natural vibration frequency of the core. 2) the high-precision joger line with stepping shearing and automatic stacking function is adopted to reduce the burr of silicon steel sheet. 3) iron core stacking adopts "stepped full oblique step lap joint technology" to improve the magnetic flux distribution at the joints. 4) PET tape is used to evenly tie the iron core to reduce the vibration of the iron core. 5) the iron core is "soft connected" with the oil tank as a whole to reduce the noise transmission of the body to the oil tank.

1) calculate the oil flow distribution, adopt a reasonable oil flow distribution structure, and reduce the winding hot spot temperature rise and average temperature rise. 2) large capacity transformer winding is set with axial oil channel. 3) control winding transverse eddy current loss.

The casing design adopts the dynamic design method, the horizontal acceleration is set as 0.5g, the waveform is set as the resonant sinusoidal third harmonic, and the loading position is the lower end of the casing flange seat. The transformer body adopts the static design method, and the static horizontal acceleration is 0.5g.

1) through software simulation, the weak points of structural parts are eliminated to improve the mechanical strength of structural parts. 2) made of high strength steel plate. 3) laser cutting equipment is used for processing, with small deformation and stress of structural parts.