Preventive measures for oil leakage of the hottest

2022-08-11
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Preventive measures for oil leakage of oil immersed transformer

1 the sealing structure should be reasonable

at present, the sealing structure of oil immersed transformer mainly includes: ① limit groove structure, and double sealing is adopted when necessary, such as the connection between the upper and lower oil tanks of the transformer; ② Flat butt joint structure. The first structure should be preferred in the design, and the seal with appropriate size should be selected. The sealing groove of the connecting flange can avoid the over compression of the sealing gasket. In the structural design of transformer oil tank, the number of welds should be reduced as much as possible, and the through-hole structure should be adopted to avoid the intersection of oil seal channels. In order to reduce the flange deformation caused by machining and welding, the flange thickness should also be appropriately increased. Using bellows soft connection is an effective way to eliminate the stress between flanges and solve the oil leakage of gas relay interface. In addition, fixing with sealant during installation can well control the compression of the seal, reduce the possibility of oil leakage, and prolong the service life of the seal

the only disadvantage of the rectangular section seal ring is that it consumes more materials, but because of its low requirements for the smoothness of the sealing surface and simple mold structure, it is a widely used seal on transformers. The compression of the rectangular section seal ring should be controlled within the range of 20% to 30%, generally preferably 30%, but for the diameter m seal, the best is 23%

o-shaped section seal ring has the greatest advantage of saving materials, but because it requires the smoothness of the two seals to be at least ra3.2 (ra3.2 is recommended for the bottom and side of the matching groove on the transformer, which can also create more economic benefits for the enterprise, ral.6 is recommended), and its own mold joint position needs to be set at 45. At the same time, the mold manufacturing cost is high, so unless the smaller sealing parts (such as vent plug, oil sample valve, etc.) are sealed with O-shaped break, it is generally not used for the sealing parts connected with the flange. The compression of the two O-ring seals is about 20% - 25%

2 select new materials

after analysis, select polymer materials with good high temperature resistance and oil resistance. It can work continuously in 150 ℃ hot oil and has good ozone resistance, ultraviolet resistance, organic solvent resistance and aging resistance

3 improve the section shape of the seal

the changes are from February 18 to March 10, respectively. In the past, circular rubber strips were used at the edge of the pressure box, which was easy to crack due to long-term stress, resulting in leakage. At present, rectangular rubber strips are used here, and double sealing structure is adopted at the same time; O-rings are used at the vent plug, oil sample valve, etc., making the "sealing structure" more reasonable

4 improve the manufacturing process level of transformer oil tank

pretreatment of steel plate and processing of all sealing surfaces to ensure the smoothness of sealing surfaces. Try to use bending structure to reduce welds. All welds in contact with oil adopt double-sided welding, and the surfaces in contact with narrow gas adopt sealing welding. Use more advanced welding technologies such as submerged arc welding and carbon dioxide gas shielded welding. At present, the more advanced welding method is high-frequency welding, which uses high-frequency current to heat and weld the metal surface locally, without welding wire and flux, without solder leakage, and can be produced continuously in large quantities

5 improve the installation quality of transformers

transformers should be installed by qualified large companies. The installation of transformer shall strictly follow the construction specifications and transformer installation instructions

before installing the seal, the flange surface should be wiped clean with a clean cloth to make the flange surface free of oil stains, metal powder and other impurities. If there are rust, burrs and grooves on the flange sealing surface, derusting, repair welding and grinding should be carried out to make the flange surface finish meet the requirements. After the installation of the transformer, the transformer shall also be subject to sealing test according to DL/dry 596

6 strengthen the quality control of purchased components

by strengthening the quality control of purchased components such as valves, radiators, casings, etc., select subcontractors in strict accordance with the IS09000 world advanced engineering plastic materials in the laboratory, strengthen the evaluation and re inspection of physical objects, improve the quality of purchased components, capture market information in time, and optimize domestic components of high quality, This can avoid oil leakage caused by purchased components

practice has proved that the above measures have achieved outstanding results in solving transformer oil leakage

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