Transformer oil leakage causes, transformer with oil plugging, transformer repair, transformer plugging, transformer repair manufacturers, transformer repair manufacturers, transformer plugging price, transformer oil leakage causes and repair technology

why

1, poor material. Poor sealing material and defect are the main reasons for leakage of transformer connection. More than 75% of transformer leakage oil is in the connection part, and the leakage oil caused by the failure of rubber seals accounts for more than 95% of the leakage oil in the connection part. Oil is leaking through the gap between the rubber seal and the connection interface. When the rubber seal does not fail, there is generally no leakage, because the rubber can fill and press the convex and concave surface under extrusion. The surface quality of the seal and the geometry of the oil leakage also have a certain impact, but the key is still the material performance of the rubber seal. Rubber seals are generally located between the upper cover of the tank, the upper and lower sections along the large and small flanges. In the operation of the transformer, they are in high temperature extrusion, oil immersion, local exposure conditions, especially the sealant on the insulating porcelain casing, with the transformer body in the vacuum tank to endure 115℃ high temperature and nearly 40h baking. Poor quality, especially the flat round rubber inside the porcelain tube, has begun to age, oil immersion began to deteriorate. Because it is in the upper part of the transformer tank, the size of the oil pressure is not uniform, although not leakage, but if the transformer movement or transportation shaking, vibration, coupled with the impact of oil will leak. Visible. Inferior rubber seals are easy to aging, deterioration, cracking, plastic deformation, and even failure. Is the main cause of oil leakage.

2. Influence of welding residual stress. Welding residual stress is another main reason for oil leakage of transformer weld. The oil tank has many solder spots, long welds, difficult welding, welding materials, welding specifications, welding technology and welding technology, etc., which will affect the welding quality. Especially, manual arc welding is more prone to weld burnthrough, porosity, slag inclusion, cracks and non-fusion defects. Among them, welding penetration defects may not be detected in the hydraulic seal test of the tank, which is also the cause of oil leakage. www.qdyuke.com

Welding is essentially a process of metal re-melting. The solution at about 1350℃ is quenched in the air, resulting in residual tensile stress of more than 200Mpa on the weld, which greatly reduces the fatigue strength. In special cases, the peak value of residual stress may be close to the fatigue strength of the weld. When the transformer is impacted and vibrated, these external forces superimpose the residual stress of the weld. Once the fatigue strength is exceeded, cracks will occur in the peak area of the residual stress but not in the defect of the penetration weld. The statistics show that the weld leakage accounts for 65%, and in the operation of the power transformer, most of the metal components are subjected to the frequency of 100HZ, the amplitude of the forced vibration is 6~60μm, the amplitude of the flat part of the box wall is 75~440μm. Because the welding seam latent residual stress, so transformer site often by impact, vibration and weld leakage oil.

3, transformer welding spot, welding seam is long. Oil-immersed power transformer is a combination of welding and connecting pieces based on steel plate welding shell. A 31500KVA transformer uses rubber seals to connect about 27 points, more than 30 rubber seals of various shapes, including the welding of both ends of the heat pipe and the fuel tank, the total welding spot is more than 70, the total length of the weld is about 20m, so the leakage way may be more. Direct leakage is caused by the failure of rubber seals and weld cracking, porosity, slag, etc.

4. Other reasons. In addition to seals and weld leakage oil, conductive copper rod of medium and small transformers, conductive copper plate of special transformers and the brazing place of the installation seat also often leak. Some manufacturers often use copper cast rod or plate instead of rolled rod or plate for various reasons. Cast copper is easy to produce porosity, loose and slag, often formed through channels and leakage. The brazing brittleness of conductive copper plate and support is very big, which may leak due to cracks in transformer installation wiring or operation, and the nut of transformer connection sealing part is often leaked due to vibration loose during transformer operation.