China's power transformers are commonly oil-immersed transformers, and oil-immersed transformers are prone to leaks and other circumstances, once the leakage, not only reduces the service life of the transformer, affecting system security, stable operation, but also to the community and the user economy Benefit has a serious impact. So what is the cause of the problem of oil spills? The reason can be listed as the following:
1. Transformer sealant aging, cracking, deformation
Transformer leakage occurred in the junction, and 95% mainly caused by the sealant. Sealant quality depends mainly on the quality of its oil resistance, poor oil resistance, aging faster, especially at high temperatures, the aging faster, can easily lead to seal aging, cracking, Metamorphosis, deformation, and even failure, resulting in transformer oil leakage.
Transformer rubber seal failure and weld cracking
Transformers have many welds and long welds, while oil-immersed transformers are a variety of welded and connected assemblies based on steel-welded shells. A 31500kVA transformer total welding points up to more than 70, total weld length of nearly 20m, so the leakage path may be more. Direct leakage is due to failure of rubber seals and weld cracking, porosity, slag and so on.
3. improper installation
Flange connection uneven, the installation of the gasket around the uniform force can not be caused by man around the gasket around the bolt non-uniform force; deformation of the flange joint dislocation, so that one side of the gasket force is too large, one side of the force is too small, Smaller force side of the seal due to lack of compression is likely to cause leakage. This phenomenon occurs in the gas relay junction and the radiator and the body connection; Another point is the gasket installation, the compression is less or too large, the amount of compression is not enough, the transformer operating temperature increase oil thinning, resulting in transformer Oil leakage, the amount of compression is too large, severe deformation of the gasket, aging accelerated service life shortened.
4. Transformer manufacturing process, but the quality of production off
Transformers in the manufacturing process, the tank of solder joints, weld long, difficult to weld, welding materials, welding specifications, technology, technology will affect the quality of welding, resulting in stomatal, trachoma, Weld, desoldering so that the transformer oil leakage .
Plate valve quality is not good
Another part of the transformer leakage often occurs in the plate butterfly valve, the earlier production of transformers, the use of ordinary plate butterfly valve connection is relatively rough, thin, single-layer seal, a phase-out products, can easily lead to transformer oil leakage.
6. caused during transport
During the transportation and construction, the parts collide with each other and are improperly hoisted and transported, causing the parts to be damaged and deformed, the welding mouth is welded, the cracks and the like occur, causing the leakage.
