Thermal oil circulation methods can be employed for on-site treatment. The adopted fault handling measures are as follows: close the gas relay tank side valve and radiator valve, and maintain the oil level of the transformer body below 30cm below the top of the tank. During the oil treatment process, the pressure gauge of the oil filter and the vacuum pressure gauge should be controlled at 0.3MPa and 0.09MPa respectively, with the outlet oil temperature preferably at 75°C, ensuring proper thermal oil circulation. When the oil temperature of the transformer body reaches 60°C, timing can commence, maintaining thermal oil circulation for 36 hours, followed by 2.5 hours of degassing from the equipment's interior. After a 24-hour standstill, insulation resistance, absorption ratio, and leakage current of the transformer's low-voltage winding should be tested.

Leakage Point Treatment: If inspection reveals leakage points in the transformer, targeted treatment should be carried out as follows.

1. Drain all transformer oil into the tank, repair welding the leakage point at the high-pressure side Dell hole, and replace damaged sealing gaskets.

2. Tighten the conductive device and nuts, ensuring secure fixation of the sealing gasket. Then, perform heating filtration and vacuum degassing of the hydrogen in the transformer oil to effectively eliminate it.

3. After completing vacuum dehydration and degassing treatment, conduct thermal oil circulation to thoroughly remove hydrogen, carbon monoxide, and carbon dioxide from the transformer oil.

4. Vacuum filling should be carried out. If oil chromatography shows normal results and relevant tests meet standards, it indicates that the fault has been rectified, and the operation can be concluded.

Other Insulation Fault Handling:

If upon inspection, it is found that the transformer has winding deformation, damaged insulation paper, or widespread loosening and detachment of insulation pads, rewinding of the winding is required. Due to factors such as on-site personnel and environmental conditions, it is often difficult to control construction processes and quality. Therefore, such faults are not recommended for on-site treatment. For such faults, it is suggested to return to the factory for specialized treatment by the transformer manufacturer.