Oil-immersed transformers

An oil-immersed transformer is a transformer that uses a liquid coolant, usually transformer oil. It is one of the most common and widely used types of transformers. Here are some details of Oil-immersed transformer:

1. Cooling and insulating oil: Oil-immersed transformers use a special transformer oil as a cooling and insulating medium. Common types of oils include mineral oils (e.g. mineral insulating oils) and synthetic oils (e.g. silicone oils). These oils have good insulating properties and thermal conductivity to efficiently cool the transformer windings.
2. Insulation system: The insulation system of an oil-immersed transformer consists of insulating oil and insulating materials. The insulating oil fills the windings and the tank of the transformer and serves to isolate and protect the windings. At the same time, the windings of the transformer are electrically insulated by solid insulating materials (e.g. cardboard, fiberboard).
3. Cooling system: Oil-immersed transformers are cooled by the circulating flow of oil. The transformer oil radiates heat through a radiator or cooler to maintain the transformer at the proper temperature. Some large transformers also use fans to assist in cooling and improve cooling efficiency.
4. short-circuit resistance: oil-immersed transformers have high short-circuit resistance due to the high thermal capacity and high dielectric strength of the oil. In the event of a short circuit, the oil can absorb and withstand a large amount of current and heat, to protect the normal operation of the transformer.
5. Maintenance and operation: oil-immersed transformers need regular inspection and maintenance, including checking the oil quality, oil level, insulation status and the cleanliness of the heat dissipation system. At the same time, transformer oil needs to be changed regularly to ensure its insulating performance and cooling effect.
6. Application areas: Oil-immersed transformers are widely used in power transmission and distribution systems, industrial plants, power plants, substations and other places. It is suitable for high-power and high-voltage applications and can provide stable power supply.

It should be noted that oil-immersed transformers may not be suitable for some special applications (e.g., indoor compact spaces or with strict environmental requirements) because they require larger installation spaces and oil handling. In these cases, dry-type transformers may be a better choice. The choice of transformer type should be evaluated and decided according to the specific application needs, installation conditions and technical requirements.