Measures to prevent oil leakage of power transformer
1 causes of oil leakage of transformer
the power transformer in our plant is an oil immersed transformer, and oil leakage has occurred from time to time for many years. Serious leakage not only reduces the service life of the transformer, affects the safe and stable operation of the system, but also puzzles the star making and standard reaching of electrical equipment for a long time. During the overhaul of 4 main transformers with capacity of 31500kVA and more than a dozen auxiliary transformers with capacity of 800kVA, 630kVA, etc., we found that the causes of transformer oil leakage are as follows:
1.1 the experimental speed can be calculated in detail by aging the sealing gasket
transformer leakage mostly occurs at the sealing gasket, which is mainly caused by aging and cracking of the sealing gasket. The quality of the sealing gasket mainly depends on its oil resistance. If the oil resistance is poor, the aging speed will be faster, especially at high temperature. It is very easy to cause the aging crack of the sealing gasket and oil leakage of the transformer.
1.2 manufacturing quality of transformer
poor casting and welding quality during the manufacturing process of transformer caused air holes, sand holes, faulty welding and desoldering, which caused oil leakage of transformer.
in 1999, during the routine overhaul of No. 4 main transformer in our plant, it was found that there was oil leakage near the low-voltage bushing at the top of the bell housing. Remove the paint and sand holes at the oil leakage place. Sometimes, in order to reduce the amount of oil leakage, non-ferrous metals such as aluminum alloy and special metal points are suddenly sprayed outward, and the oil column is up to about 1m. This is the leakage caused by the pores left during the casting of a typical transformer shell.
1.3 the quality of the plate butterfly valve is poor.
another part of the transformer that often leaks is at the plate butterfly valve. The connection surface of the ordinary plate butterfly valve used in the transformer produced earlier is rough, thin and single-layer sealed. It is an obsolete product, which is very easy to cause oil leakage of the transformer.
1.4 improper installation method
the flange connection is uneven, so Yunnan should surpass the fact that as the helmsman of the new era, the sealing gasket cannot be evenly stressed around during installation; Uneven stress of bolts around the sealing gasket caused by human activities; The flange joint is deformed and misaligned, so that the stress on one side of the gasket is too large and the stress on the other side is too small. The gasket on the side with too small stress is easy to cause leakage due to insufficient compression. This phenomenon often occurs at the connection of gas relay and the connection between radiator and body; Another point is that when the gasket is installed, its compression is insufficient or too large. When the compression is insufficient, the operating temperature of the transformer increases and the oil becomes thin, resulting in oil leakage of the transformer, large compression, serious deformation of the gasket, accelerated aging and shortened service life.
1.5 improper shipping
collision and incorrect hoisting and transportation of parts and components during shipping and construction transportation, resulting in damage and deformation of parts, open welding of welded junctions, cracks, etc., resulting in leakage.