Before dealing with oil leakage, it is necessary to carefully analyze and find out the cause and exact leakage point. For the existing oil spots, first use a small flat shovel and wire brush to clean, then use xylene to clean, use clean water to wash, and then use a clean cloth to clean repeatedly to find the exact location of the leakage point.

The leakage of transformer can be divided into sealing leakage and welding leakage. The main way to deal with seal leakage is to improve the seal quality. For example, if the fastening screw is invalid, the seal ring can be replaced or glued again for the casing, oil mark, radiator valve, large cover, on load switch and other parts with seals; Repair welding can be used to deal with welding leakage. No matter what kind of oil leakage is handled, the thick material method or binding method shall be prohibited.

1. Seal

The pressure bearing area of the sealing rubber should match the force of the screw, otherwise it is difficult to compress; When replacing the rubber sealing ring of the rubber plug, the valves and passageways at each inlet of the component should be closed and replaced under the condition that the negative pressure is kept to a large amount of oil. The seals should have good oil resistance and anti-aging performance, good elasticity and mechanical properties, and seal materials should avoid using asbestos packing and cork pads as far as possible.

The parts with poor structure or unreasonable sealing method, such as the connecting flange of radiator and oil purifier, are not strong enough and easy to deform when tightening the bolts, so that the flange can not press the gasket tightly, should be transformed or replaced. The crimping plane of the sealing place should be smooth and clean. When placing the rubber pad, a layer of adhesive liquid, such as polyvinyl chloride and varnish, should be applied first.

2. Welding

When leakage is found on the upper part of transformer oil tank, only a small amount of oil needs to be discharged for welding treatment; When the leakage is found at the lower part of the oil tank, due to the waste of core lifting oil and the limitation of site conditions, the welding with oil can be used. The repair welding with oil should be carried out under the condition that the oil leakage is not obvious, otherwise the vacuum drainage method should be used to cause negative pressure before welding. The vacuum degree of negative pressure should not be too high, and the internal and external pressure should be equal, so as to avoid the inhalation of molten iron.

Gas welding is generally prohibited for repair welding with oil; It is better to use fine welding rods such as 422 and 425; During repair welding, the oil stains on the welding parts shall be removed, and the oil stains shall be washed with alkaline water and then dried; Pay attention to prevent penetration and fire during welding, and the welding position must be below the oil level; Intermittent and rapid spot welding shall be adopted during welding. The arc burning time shall be controlled within 10s ~ 20s, and long-time continuous welding is not allowed.

When repairing the pores with serious oil leakage, iron wire can be used to plug or rivet them before welding; When welding near the sealing rubber gasket or other vulnerable parts, cooling and protection measures shall be taken.

3. Sand hole

The sand hole on the casting can be blocked by Diyou 1 plugging glue under pressure. After blocking, attention should be paid to reinforcing, and then the sand hole should be baked with electric blower for 5-15 minutes until curing.