Oil Immersed Transformer

An oil-immersed transformer, also known as an oil-filled transformer, is an electrical device that transfers electrical energy between two or more voltage levels using oil as the cooling and insulating medium. Unlike dry-type transformers, oil-immersed transformers are commonly used in high-voltage applications, such as power generation plants, substations, and industrial settings.

Here are some key features and components of an oil-immersed transformer:

Core and Windings:

The core is typically made of laminated steel sheets to minimize magnetic losses.

The windings consist of copper or aluminum conductors that are insulated and placed around the core. The windings are responsible for transferring electrical energy between the primary and secondary circuits.

The windings are immersed in insulating oil to provide efficient cooling as well as electrical insulation.

Insulating Oil:

The insulating oil used in oil-immersed transformers is typically mineral oil, which has good dielectric properties and thermal conductivity. It helps in dissipating heat and providing electrical insulation.

The oil also acts as a coolant, removing heat generated during the transformer's operation.

Tank and Cooling System:

Oil-immersed transformers are housed in a tank made of steel or other suitable materials. The tank provides structural support and seals the transformer, preventing moisture and contaminants from entering.

The tank is equipped with cooling fins or radiators, which increase the surface area for better heat dissipation.

An oil circulation or forced oil cooling system may also be present to enhance cooling efficiency.

Tap Changer:

Oil-immersed transformers often have a tap changer, which allows for adjustment of the turns ratio to regulate the output voltage under varying load conditions.

Tap changers can be either on-load or off-circuit types, each with its own method of adjusting the turns ratio.

Accessories and Protections:

Oil-immersed transformers may have various accessories, such as temperature sensors, pressure relays, and Buchholz relays, which monitor and protect the transformer against abnormal operating conditions, such as overheating, overpressure, or internal faults.

Breathers and silica gel breathers are used to control the moisture levels inside the transformer tank, preventing the formation of corrosive gases and maintaining the dielectric properties of the insulating oil.

Oil-immersed transformers are known for their durability, reliability, and high power-handling capabilities. Regular maintenance, including oil testing, periodic inspections, and servicing, is essential to ensure efficient operation and prolong the transformer's lifespan. It is crucial to follow manufacturer guidelines, industry standards, and safety procedures when installing, operating, and maintaining an oil-immersed transformer. Consulting with a qualified professional or transformer specialist is always recommended for any specific requirements or concerns regarding oil-immersed transformer systems.