Types and Performance Characteristics of Oil-immersed Transformers

The low-voltage windings of oil-immersed transformers generally adopt a cylindrical structure with copper foil winding except for small-capacity copper wires; the high-voltage windings adopt a multi-layer cylindrical structure, so that the ampere-turn distribution of the winding is balanced and the magnetic flux leakage is small. High mechanical strength and strong short-circuit resistance.

Ⅰ. Oil-immersed transformer cooling method

The cooling method of the oil-immersed transformer is oil circulation cooling, and the oil channel is used for heat dissipation. Each transformer has an oil tank, which is characterized by good heat dissipation. Compared with dry-type transformers, they are flammable, require frequent maintenance, and cause certain pollution to the environment. Therefore, oil-immersed transformers are rarely used in areas with high population density. But considering the cost is lower than the dry type. In consideration of safe operation, maintenance cost and environmental protection, dry-type transformers are recommended.

Ⅱ. Oil-immersed transformer type

1. Non-enclosed oil-immersed transformers are widely used in industrial and mining enterprises, agriculture and civil buildings.

2. Closed oil-immersed transformers are mostly used in places with a lot of oil and chemicals in the petroleum and chemical industries.

3. The sealed oil-immersed transformer can be used for power distribution in various places such as industrial and mining enterprises, agriculture, and civil buildings.

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 thyristor circuits, voltage transformers and current transformers for measuring instruments.

Ⅲ. Performance characteristics of oil-immersed transformers

1. The low-voltage windings of oil-immersed transformers generally adopt a cylindrical structure with copper foil winding except for small-capacity copper wires; the high-voltage windings adopt a multi-layer cylindrical structure to balance the ampere-turn distribution of the winding and prevent magnetic flux leakage Small, high mechanical strength, strong short circuit resistance.

2. The iron core and the winding are respectively fastened. The fastening parts such as the height of the device and the low-voltage lead wire are equipped with self-locking locknuts. The non-suspending structure is adopted, which can withstand the vibration of transportation.

3. The coil and iron core are vacuum-dried, and the transformer oil is vacuum-filtered and oil-filled to minimize the moisture inside the transformer.

4. The oil tank adopts corrugated sheet, which has a breathing function to compensate the volume change of oil caused by temperature changes, so this product has no oil storage tank, which obviously reduces the height of the transformer.

5. Since the corrugated sheet replaces the oil conservator, the transformer oil is isolated from the outside world, which effectively prevents the entry of oxygen and moisture and leads to a decrease in insulation performance.

According to the performance of the above five points, it is guaranteed that the oil-immersed transformer does not need to change oil during normal operation, which greatly reduces the maintenance cost of the transformer and prolongs the service life of the transformer.