ABOUT TIANYI

1. Rubber seal failure and weld cracking

Transformers have many welding spots and long welding seams, while oil-immersed transformers are a collection of various welding and connections based on steel plate welded shells.

A 31500kVA transformer has a total of more than 70 welding joints, and the total length of the welding seam is about 20m, so there may be many leakage channels. The cause of direct leakage is the failure of rubber seals and weld cracks, pores, slag inclusions, etc.

2. The sealant parts are aging, cracked and deformed

Transformer leakage mostly occurs at the connection, and more than 95% is mainly caused by the sealant. The quality of the sealant mainly depends on its oil resistance. If the oil resistance is poor, the aging rate will be faster. Especially at high temperatures, the aging rate will be faster, which will easily cause the seal to age and crack. Deterioration, deformation, and even failure, causing oil leakage of the transformer.

3. The manufacturing quality of the transformer

In the transformer manufacturing process, many welding spots in the fuel tank, long welding seams, difficult welding, welding materials, welding (classification characteristics of welding process equipment) specifications, processes, technology, etc. will affect the welding quality, resulting in pores, sand holes, false welding, and desoldering This phenomenon causes the transformer to leak oil.

4. The quality of the plate butterfly valve is not good

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 relatively rough, thin, and single-layer sealed. It is an obsolete product and is very easy to cause transformer oil leakage.

5. Improper installation method

The flange connection is not flat, and the gasket can not be evenly stressed during installation; the bolts around the gasket are artificially caused to be unevenly stressed; the flange joint is deformed and misaligned, so that the force on one side of the gasket is too large, and the force on one side is too small. The gasket on the side with a small force is likely to cause leakage due to insufficient compression. This phenomenon mostly occurs at the connection of the Buchholz relay and the connection between the radiator and the 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 will rise and the oil will become thinner, causing the transformer Oil seepage, the compression is too large, the gasket is deformed seriously, and the aging accelerates the service life and shortens.　

6. Improper consignment

Collision of parts during consignment and construction and transportation, as well as incorrect hoisting and transportation, caused parts to be damaged and deformed, weld openings, cracks, etc., causing leakage.