Oil immersed Power transformer classification

According to the number of phases of a single transformer, it can be divided into three-phase transformers and single-phase transformers. In a three-phase power system, a three-phase transformer is generally applied. When the capacity is too large and limited by the transportation conditions, three single-phase transformers can also be used to form a transformer group in the three-phase power system.

According to the number of windings, it can be divided into two-winding transformer and three-winding transformer. A typical transformer is a two-winding transformer, that is, there are two windings on the core, one for the primary winding and one for the secondary winding. The three-winding transformer is a larger capacity transformer (above 5600 kVA) for connecting three different voltage transmission lines. In special cases, there are also transformers that use more windings.

Classified according to the structure, it can be divided into iron core transformer and iron shell transformer. If the winding is wrapped around the core, it is a core-type transformer; if the core is wrapped around the winding, it is an iron-shell transformer. The two are only slightly different in structure, and there is no essential difference in principle. Power Transformers are all iron core type.

According to insulation and cooling conditions, it can be divided into oil-immersed transformers and dry-type transformers. In order to strengthen the insulation and cooling conditions, the core and windings of the transformer are immersed together in a tank filled with transformer oil. In special cases, such as street lights and mine lighting, dry-type transformers are also used.

In addition, there are special transformers for various special purposes. For example, high-voltage transformers for testing, transformers for electric furnaces, transformers for electric welding, and transformers for use in thyristor circuits are used to measure voltage transformers and current transformers of meters.

In the operation of the oil-immersed Power Transformer, the heat of the winding and the iron core is first transmitted to the oil and then transmitted to the cooling medium through the oil. The cooling method of the oil-immersed power transformer can be divided into the following types according to the capacity:

1. Natural oil circulation natural cooling (oil immersed self-cooling)

2. Natural oil circulation air cooling (oil immersion air cooling type)

3. Force oil circulation water cooling

4. Forced oil circulation air cooling

Oil-immersed Transformer normal use conditions

Altitude up to 1000m indoors or outdoors

Maximum ambient temperature +40°C maximum daily average temperature +30°C

The highest annual average temperature +20 ° C, the lowest temperature -25 ° C

Transformers that operate under special conditions of use are available upon request.