1. Directly cause internal short circuits, leading to transformer burnout

After winding deformation, the distance between turns and coils changes, leading to localized insulation being compressed, rubbed, and damaged.

The original support structure of the winding became loose, causing the conductors to lose their fixation and further misalign under operational vibrations and current impacts.

Highly prone to trigger:

interturn short circuit

Interlayer short circuit

phase-to-phase short circuit

Ground flashover of winding

After a short circuit occurs, the oil temperature inside the transformer rises sharply, the insulation carbonizes, and ultimately leads to fire, explosion, and complete scrapping, making it nearly impossible to repair.

2. The short-circuit resistance capability drops sharply, and damage occurs immediately upon impact

When a power grid experiences an outlet short circuit, local fault, or lightning strike, it generates significant electromagnetic forces.

A normal transformer can withstand multiple short-circuit impacts, whereas the mechanical strength of the deformed winding has become severely inadequate.

A strong short-circuit current may cause the winding to:

completely disintegrated

Axial compression, radial bulging

Conductor breakage and displacement

Manifested as: Whenever there is a power grid failure, the transformer is damaged first, leading to a large-scale power outage.

3. Trigger severe partial discharge, accelerating insulation aging and failure

Deformation causes severe uneven distribution of the electric field within the winding, leading to localized field concentration and sustained partial discharge.

Partial discharge continuously erodes insulation, leading to:

Solid insulation embrittlement and powdering

Insulating oil decomposes and generates a large amount of gas

The insulation performance continues to decline

Defects can progress from minor deformations to fatal failures over time, with no obvious noise or overheating in the early stages, making them difficult to detect manually.

4. Causes localized overheating, excessive temperature rise, and significant lifespan reduction

Winding deformation alters the leakage flux path, leading to increased leakage flux and disrupted distribution.

Local overheating occurs at areas such as the tank wall, clamping components, pressure screws, and core, with abnormal temperature rises.

Prolonged overheating can lead to:

Insulation rapid aging

Accelerated deterioration of insulating oil

The mechanical strength of the winding further decreases

The service life of transformers has been significantly shortened, reducing from originally over a decade to possibly requiring replacement within just a few years.

5. Causing misoperation or failure to operate of protection, thereby escalating power grid accidents

Winding deformation can lead to:

Excitation characteristic change

DC resistance imbalance

The transformation ratio error increases

Impedance voltage anomaly

It may cause misoperation of differential protection, gas protection, and overcurrent protection, leading to unnecessary tripping.

Severe deformation may also lead to reduced protection sensitivity, failure to operate, and inability to promptly remove faults.

The minor fault eventually escalated into a major accident, affecting the entire line, busbar, and even the safety of the substation.

6. Operation shows no obvious signs, with a high risk of sudden failure

Early-stage winding deformation shows almost no external characteristics

The sound is normal

The oil temperature is normal

No abnormality in appearance

Only through winding deformation tests (frequency response analysis FRA, low-voltage short-circuit impedance method) can an accurate judgment be made.

Many transformers appear to operate normally but suddenly fail, explode, or burn out without any warning.

7. The maintenance cost is extremely high, or even directly scrapped

Winding deformation is a type of internal structural damage that cannot be easily repaired on-site.

It must be returned to the factory for major repairs: core lifting, disassembly, rewinding, drying, and testing, which are costly and time-consuming.

When the deformation is severe, the entire component must be scrapped and replaced, resulting in significant economic losses.