Oil-immersed transformer has the characteristics of good heat dissipation, low loss, large capacity and low price. At present, most of the power transformers operating on the power grid are oil-immersed transformers, and more than 80% of them are cooled by natural oil circulation. The setting of a guide plate in the coil of a natural oil circulation transformer is a commonly used cooling structure now. This article focuses on analyzing the structure, operation and maintenance of oil-immersed power transformers, and specifically analyzes the oil system of oil-immersed power transformers, and briefly analyzes the faults of oil-immersed power transformers. We hope to increase our understanding and analysis of oil-immersed power transformers in our country.
The oil tank is the outer shell of the transformer, and the iron core and windings are installed in it and filled with transformer oil. For transformers with relatively large capacity, radiating fins or radiating pipes are installed outside the oil tank. Oil leakage is a common problem with fuel tanks.
Transformer oil is a kind of mineral oil with good insulating properties. It has two functions:
One is insulation. Transformer oil has better insulation performance than air. Soaking the windings in the oil can improve the insulation performance of all parts and avoid contact with air to prevent the windings from getting damp;
The second is the role of heat dissipation, using the convection of the oil to dissipate the heat generated by the iron core and windings to the outside through the box wall and the heat dissipation pipe. Transformer oil is divided into three specifications of No. 10, No. 25, and No. 45 based on its freezing point. Their freezing points are -10 ℃, -25 ℃, and -45 ℃ respectively, which are generally selected according to local climatic conditions.
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