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Transformer winding deformation characteristics

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Update time : 2018-08-15 11:07:23
Braking by the sudden braking of the transport vehicle or the transport ship, the overall displacement of the transformer winding is deformed. This deformation is mainly in transit. Transformer body by more than 3gg for the acceleration of gravity) The acceleration of gravity impact, it will be possible to make the whole coil in the radial direction to a significant displacement.
Found that the deformation of the power transformer winding is the direct cause of a variety of faults and accidents. Once the transformer windings have been severely deformed and are not diagnosed, they continue to run and are analyzed afterwards by checking for transformers that have failed or failed. It is very likely to lead to the accident, the light caused by blackouts, heavy ones will probably burn the transformer. Cause the deformation of the winding, the main reason is the lack of strength of the winding mechanical structure, winding process rough to accept the normal allowable short-circuit current impact and external mechanical impact poor. Therefore, the deformation of the transformer windings is mainly influenced by the internal and external mechanical forces. The influence of electrodynamic force is the most prominent. For example, the short-circuit impulse current and the generated electromotive force caused by the short-circuit of the transformer inlet will distort, deform and even disintegrate the windings.
1.1 high-voltage winding in the outer layer. So that the end of the winding pressure nail loose, pad fly out, serious, the iron yoke clip pull plate, the fastening strip will be deformed, the winding loose to increase its height, by the axial tensile stress and radial expansion stress .
1.2, the location of low-voltage winding in the column or in the middle. So that the end of the winding fastening pressure nail loose, pad displacement; inter-turn pad displacement, stay tilt, wire cake in the radial direction was polygonal distortion. If the deformation is light, such as 35kv wire cake without deformation. The inner circumference of a twist, radiating upward inwardly, the winding lining is soft when the deformation of the drum is particularly evident. If the transformer is short-circuit impact, the relay maintenance delay action more than 2s deformation is more serious, wire cake will have a larger area of the concave, upturned phenomenon. When measuring the entire winding is often highly reduced, if the transformer continues to put into operation the transformer tank vibration will be significantly increased. Lateral leakage magnetic field so that the short circuit when the wire pie by electric force is much larger than normal,
Winding winding area 1.3, the junction area of cake piecing deformation. This is due to unbalanced ampere turns in the tap area and the entanglement area (usually at the beginning of the winding). So prone to deformation and damage. In particular, the taping line cake, tapped by the on-load tap-changer caused short-circuit fault, the winding will be deformed into a wavy shape, which affects the insulation and the smooth flow of oil.
1.4 winding lead displacement distortion. This is what happens after a transformer short circuit fault. The insulation distance of the winding lead arrangement is broken. If the lead is too close to the tank wall, it will cause discharge. The distance between the leads is too close. The insulation will be damaged due to friction, which will lead to latent faults and may develop into a short circuit accident.