Advantages of Oil-Immersed Transformers

Excellent Cooling Performance
The transformer oil used in oil-immersed transformers serves as an effective coolant, absorbing heat generated during operation and transferring it to the transformer's cooling system (e.g., radiators). This allows oil-immersed transformers to handle high power loads and maintain stable operation even in continuous heavy-duty conditions.

Superior Insulation Properties
Transformer oil provides strong electrical insulation, reducing the risk of short circuits and enhancing the reliability of the transformer. Additionally, it can prevent the degradation of internal insulation materials, extending the equipment's service life.

High Overload Capacity
Oil-immersed transformers can temporarily withstand overloads due to the heat dissipation and insulation capabilities of the transformer oil. This makes them suitable for power systems with fluctuating loads or sudden demand surges.

Mature Technology and Cost-Effectiveness
The technology for oil-immersed transformers has been developed for a long time, with a stable manufacturing process and relatively low production costs—especially for large-capacity transformers. They are also widely used in power grids, making maintenance and repair more convenient due to mature technical support.

Self-Healing Insulation
Transformer oil can saturate the solid insulation materials (e.g., paper and cardboard) inside the transformer, forming a dense insulation system. In case of minor insulation damage, the oil may help delay the spread of damage through its insulation properties.

Disadvantages of Oil-Immersed Transformers

Risk of Oil Leakage and Environmental Concerns
Transformer oil leakage can occur due to aging seals, mechanical damage, or manufacturing defects. Oil spills may contaminate soil and water, posing environmental risks. Additionally, traditional mineral oil is non-biodegradable, requiring strict environmental protection measures during disposal or replacement.

Fire and Explosion Hazards
Transformer oil is flammable. In the event of internal faults (e.g., short circuits or arc discharges), high temperatures may ignite the oil, leading to fire or even explosions. This requires strict installation regulations, such as placing transformers in fireproof rooms or outdoor areas with fire barriers.

Complex Installation and Maintenance
Oil-immersed transformers require regular inspection of oil quality (e.g., moisture content, acidity, and breakdown voltage), as well as periodic oil replacement or filtration. They also need a sealed casing and cooling system, making installation more complex—especially in indoor or confined spaces.

Limited Application in Specific Environments
Due to fire and environmental risks, oil-immersed transformers are restricted in areas with high fire safety requirements (e.g., urban centers, commercial buildings, or chemical plants). They may also face challenges in cold regions where the oil's viscosity increases, affecting cooling performance.

Higher Weight and Space Requirements
Oil-immersed transformers are heavier and bulkier than dry-type transformers due to the inclusion of oil and cooling components. This increases transportation and installation difficulties, especially in scenarios with strict space limitations.

In summary, oil-immersed transformers are favored for their high power capacity and reliability in medium-to-large power systems, but their application requires careful consideration of environmental, safety, and maintenance factors.