The oil leakage faults of oil-immersed transformers shall be handled in strict accordance with the standardized process of leakage location – classified disposal – acceptance verification, and all on-site power safety operation regulations shall be strictly implemented throughout the whole process.

Trace the actual leakage points along oil stains, which are commonly found on box welds, flange joints, butterfly valves and bushing roots. Thoroughly clean oil dirt and rust around leakage areas until the original metal surface is exposed without any residual impurities.

For slight oil leakage without immediate power cut conditions, apply oil-resistant and high-temperature resistant special epoxy leakage stopping adhesive to leakage points, or fasten flange bolts diagonally. Auxiliary sealant can be used for slightly aged sealing gaskets. This method is only for emergency treatment, and thorough maintenance shall be arranged as soon as possible after power outage.

Replace with oil-resistant nitrile rubber gaskets with Shore A hardness of 70±5, and control the gasket compression rate within 1/3~2/5. Ensure flat flange surfaces, evenly coat sealant and fasten bolts evenly in diagonal sequence. Replace outdated butterfly valves with ZF80 vacuum eccentric butterfly valves uniformly.

Drain transformer oil below the leakage position. Perform spot welding for tiny pinholes; drill crack stop holes, fill gaps and conduct surfacing welding with thin welding rods for large cracks. For cast iron components, drill crack stop holes and adopt lead wire riveting or professional welding for repair.

Wrap oil-resistant PTFE tape or apply thread sealant on threaded joints. Disassemble, clean and reassemble severely damaged threads with new spring lock washers.

Carry out air tightness leakage test under 0.03 MPa pressure for 30 minutes after oil filling. Conduct oil chromatographic analysis after oil replenishment. Strengthen patrol inspection focusing on original leakage points within 24 to 48 hours after transformer puts into operation.

Welding operation with large residual oil inside the transformer is strictly forbidden to avoid fire and explosion hazards. It is prohibited to adopt simple measures such as thick gaskets or plastic binding for makeshift treatment, and ordinary civil adhesives shall not be used for long-term leakage sealing.

In case of severe oil spraying or sharp oil level drop, transfer load and cut off power supply immediately to prevent insulation breakdown and electrical fire accidents.