The leakage of oil-type transformers can be roughly divided into sealing leakage and welding leakage. If there is a problem, it should be checked and judged and resolved accordingly.
Before dealing with oil leakage, it is necessary to analyze carefully to find out the cause of the leakage and the exact leakage point. For the existing oil stains, first use a small flat spatula and a wire brush to clean up, then wash with xylene, rinse with clean water, and then repeatedly wipe with a clean cloth to find the exact location of the leak.
Transformer leakage can be roughly divided into sealing leakage and welding leakage. Dealing with seal leakage is mainly to improve the sealing quality. For example, for casings, oil gauges, radiator valves, large covers, on-load switches and other seals, if the tightening screws are invalid, the seal ring can be replaced or re-glued and sealed ; To deal with welding leakage, repair welding can be adopted. No matter what kind of oil leakage is handled, the thick material method or lashing method should be prohibited.
The pressure-bearing area of the sealing rubber should be compatible with the strength of the screw, otherwise it will be difficult to compress; when replacing the rubber sealing ring of the oil plug, the valves and passages at the entrance of the component should be closed, and the negative pressure should be maintained until a large amount of oil is discharged. Under the circumstances, the seal should have good oil resistance and anti-aging properties, better elasticity and mechanical properties, and the sealing material should avoid the use of asbestos packing and cork pads as much as possible.
Components with poor structure or unreasonable sealing methods, such as radiator and oil purifier coupling flanges are not strong enough, and are easily deformed when the bolts are tightened, so that the flange cannot tightly press the gasket, and should be modified or replaced. The crimping surface of the seal should be smooth and clean. When placing the rubber pad, it is better to apply a layer of adhesive glue such as polyvinyl chloride, varnish, etc.
When a leakage is found in the upper part of the transformer tank, only a small amount of oil can be discharged for welding; when a leakage is found in the lower part of the tank, because the lifting core is too wasteful and limited by site conditions, welding with oil can be used. Repair welding with oil should be carried out when the oil leakage is not significant. Otherwise, the vacuum drain method should be used to cause the negative pressure to be welded. The vacuum degree of the negative pressure should not be too high. The internal and external pressures should be equal to avoid inhaling molten iron.
Gas welding is generally prohibited for repair welding with oil; thinner electrodes such as 422 and 425 electrodes should be used for welding; the oil traces on the welding part should be removed when repairing, so that it can be washed with alkaline water and then wiped dry; during welding Pay attention to prevent penetration and fire, and the welding site must be below the oil level; intermittent and rapid spot welding should be used when welding, and the arcing time should be controlled within 10s to 20s. Long-term continuous welding is not allowed.
When repairing the pores with serious oil leakage, use iron wire to block or riveting before welding; when welding close to the sealing rubber gasket or other vulnerable parts, cooling and protective measures should be taken.
The blisters on the castings can be blocked by pressure with Diyou No. 1 plugging glue. After the blockage is completed, pay attention to reinforcement, and then use a hair dryer to bake for 5min to 15min until solidified.