Transformer Cooling (A Different Type of “Oil”)
This is a special case where the “oil” is a dielectric insulating fluid, not a lubricant.
- What it cools: Transformer insulating oil.
- Source of Heat: Electrical losses (I²R losses) from the transformer windings and core.
- Why it’s critical: The oil serves two purposes: it electrically insulates and it cools. The cooler the oil, the more power (MVA) a transformer can handle. Overheating drastically shortens the life of the paper insulation around the windings, leading to premature transformer failure.
- Cooler Type: Radiators (finned banks) that allow air to naturally or forcedly (fans) cool the oil. Large transformers may use oil-to-water heat exchangers.