Transformers typically use **mineral oil** or **synthetic oils** as insulating and cooling fluids. The primary purpose of the oil is to provide insulation between the internal components and to dissipate heat generated during the transformer’s operation.
### Types of Oil Used:
1. **Mineral Oil**:
- This is the most common oil used in transformers. It’s a type of oil derived from petroleum and refined for use in electrical equipment.
- Mineral oil has good insulating properties and is effective at transferring heat away from the transformer’s core and windings.
2. **Silicone Oil**:
- Used in some specialized transformers, silicone oil has better thermal stability than mineral oil. It can be used in environments with higher temperatures or when there are specific environmental concerns.
3. **Synthetic Esters**:
- These are biodegradable oils made from plant-based or synthetic materials. They are often used in environmentally sensitive areas because they are less harmful if spilled.
4. **Natural Esters**:
- Similar to synthetic esters but derived from vegetable oils. These are becoming more popular due to their environmental friendliness and fire-resistant properties.
The choice of oil depends on factors like the transformer’s operating conditions, environmental concerns, and safety requirements.