Structural classification of oil-immersed transformer

The oil-immersed transformer can be divided into iron core type oil-immersed transformer and iron shell-type transformer. If the winding is wrapped around the iron core, it is an iron-core type oil-immersed transformer. For example, the core is wrapped around the winding, and the oil-immersed transformer is an iron-shell type. The two are just slightly different in structure, and there is no essential difference in principle. The oil-immersed transformer is mainly composed of an iron core, winding, oil tank, oil pillow, insulating sleeve, tap changer, and gas relay. Next, let us take a look at the structure classification of transformer.

This is the content list:

l The core of the oil-immersed transformer

l Winding of oil-immersed transformer

l The oil tank of the oil-immersed transformer

The core of the oil-immersed transformer

The iron core is the magnetic circuit part of the transformer. The oil-immersed transformer will generate hysteresis loss and eddy current loss during operation and generate heat. To reduce heat loss and volume and weight, the oil-immersed transformer core is made of a cold-rolled grain-oriented silicon steel sheet with high permeability of less than 0.35mm. According to the winding arrangement in the transformer iron core, there are iron core type and iron shell type.

In a large-capacity oil-immersed transformer, to make the heat emitted by the oil-immersed transformer core loss can be fully taken away by the insulating oil during circulation, to achieve a good cooling effect, it is often installed in the oil-immersed transformer core There are cooling oil passages.

Winding of oil-immersed transformer

Both the winding and the iron core are the core components of the transformer. Since the oil-immersed transformer winding itself has resistance or there is contact resistance at the joint, it is known from Joule's law to generate heat. Therefore, the oil-immersed transformer winding cannot pass a current higher than the rated current for a long time. In addition, when a short-circuit current is passed, a large electromagnetic force will be generated on the winding of the transformer to damage the transformer. The basic oil-immersed transformer winding has two types: concentric and overlapping.

The main faults of the oil-immersed transformer winding are short-circuited between turns and short-circuit to the shell. The turn-to-turn short circuit is mainly caused by the aging of the insulation, or due to the overload of the oil-immersed transformer and mechanical damage to the insulation during the short circuit. The oil level in the transformer drops so that when the windings are exposed to the oil level, a short circuit between turns can also occur. In addition, when the transformer passes through a short circuit, the winding of the transformer is deformed due to the effect of overcurrent, which causes mechanical damage to the insulation and also causes a short circuit between turns. When the oil-immersed transformer turns short-circuit, the current in the short-circuit winding may exceed the rated value, but the entire transformer winding current may not exceed the rated value. In this case, the oil-immersed transformer gas protection will operate, and the differential protection device will also operate when the situation is serious. The short circuit to the oil-immersed transformer shell is also caused by the oil-immersed transformer insulation aging, oil damp, oil level drop, or lightning and operating overvoltage. In addition, when the transformer crosses a short circuit, the winding of the transformer is deformed due to overcurrent, which will also cause a short circuit to the shell. When the shell of the oil-immersed transformer is short-circuited, the gas protection device and grounding protection are usually activated.

The oil tank of the oil-immersed transformer

The body (winding and iron core) of the oil-immersed transformer is installed in an oil tank filled with transformer oil, and the oil-immersed transformer tank is welded with steel plates. The oil tank of medium and small oil-immersed transformer consists of a case and a case cover. The body of the oil-immersed transformer is placed in the case, and the oil-immersed transformer can be lifted out for maintenance by opening the cover of the oil-immersed transformer.

Zhejiang Shuntong Electric Co., Ltd. is a professional manufacturing enterprise integrating development, production, sales, and service. The company was established in 2009 and is located in Liushi Town, "China's Power Capital", specializing in the production of various high and low voltage equipment. The main products are dry-type transformers, oil-immersed transformers, special transformers, box-type substations, cable junction boxes, high and low voltage complete sets of equipment, voltage regulating equipment, etc. The above is related to the structure classification of oil-immersed transformer. The company has a clear understanding of the structural classification of oil-immersed transformers, and the selected materials are of good quality. If you are interested in an oil-immersed transformer, please contact us, our website is www.sntoom.com.