Summary Of Various Problems Of Transformer Oil Leakage

There are two main reasons for leakage: On the one hand, it is the legacy problems in the transformer design and manufacturing process; on the other hand, it is caused by improper installation and maintenance of the transformer. The main leakage parts of the transformer often appear in the radiator interface, flat disc valve cap, bushing, porcelain bottle, weld, sand hole, flange and other parts.

The transformer leakage is mainly concentrated in the following parts: more than 50% of the total leakage points are radiator interface, flat disc valve cap, radiator blind head, connection flange seal; 16% are leakage of bushing and porcelain bottle; 12% are leakage of gas relay interface and other parts. In addition, there are some defects in the manufacturing process of the transformer, such as welds, sand holes, etc.
1. Treatment of oil leakage at welding: The cause of the problem: mainly poor welding quality, virtual welding, desoldering, pinholes, sand holes and other defects in the weld. The transformer is covered with flux and paint when it leaves the factory, and the hidden dangers are exposed after operation. In addition, electromagnetic vibration will cause welding vibration cracking, causing leakage.
Solution to the problem: For leakage, first find the leakage point, and do not miss it. It needs to be cleaned continuously, and the source of leakage should be found along the oil traces. The leak point should be sealed with a water-oil compatible filler. After solidification, the purpose of long-term leakage control can be achieved.
2. Causes of oil leakage in cast iron parts: The main cause of oil leakage is sand holes and cracks in cast iron parts.
Solution to the problem: ① For crack leakage, drilling crack-stopping holes is a method to eliminate stress and avoid extension. During treatment, lead wire can be driven into the leak point or riveted with a hand hammer according to the situation of the crack. Then clean the leak point with acetone, and seal it with a water-oil compatible filler and titanium steel glue
3. Causes of oil leakage in radiators: The heat pipes of radiators are usually made of seamed steel pipes that are flattened and stamped. Oil leakage often occurs in the bending and welding parts of the heat pipes. This is because when stamping the heat pipes, the outer wall of the pipe is under tension, and the inner wall is under pressure, resulting in residual stress.
Technical solution to the problem: After determining the leakage site, appropriate surface treatment is performed. First, titanium steel glue is used for rapid sealing and sealing treatment. After solidification, water-oil compatible repair agents are used for reinforcement.
4. Causes of oil leakage at flange connection: uneven flange surface, loose fastening bolts, incorrect installation process, poor fastening of bolts, aging and cracking of seals, resulting in oil leakage.
Technical solution: first tighten the loose bolts, then use water-oil compatible repair agent to seal the bolts, and then treat the leaking flange surface to achieve complete control. Tighten the loose bolts,
5. Causes of oil leakage at seals: poor sealing. Usually, the seal between the box edge and the box cover is sealed with oil-resistant rubber rods or rubber pads. If the joint is not properly handled, it will cause oil leakage. Due to installation reasons, the interface cannot be pressed firmly and cannot play a sealing role, and it still leaks oil.
Technical solution: Use water-oil compatible repair agent for bonding to make the joint form a whole, and the oil leakage phenomenon is greatly controlled; if the operation is convenient, the metal shell can also be bonded at the same time, including the bolt part, to achieve the purpose of leakage control.
6. The cause of oil leakage from bolts or pipe threads: rough processing and poor sealing at the factory. After a period of time, the transformer will leak oil.
Technical solution: Use water-oil compatible repair agent to seal the bolts to achieve the purpose of leakage control.
7. The cause of oil leakage from porcelain bottles and glass oil markers: usually due to improper installation or sealing failure. The leakage point usually exists at the junction of the porcelain bottle and the base. Technical solution: Use water-oil compatible repair agent and reinforcement belt to wrap and seal the leakage point as a whole