Transformer oil is primarily used for insulation, cooling, and arc extinguishing. Types include mineral oil, vegetable oil, silicone oil, synthetic ester oil, and nano-modified oil. Wenzhou Best Imp. &Exp. Co., Ltd.
Main Functions of Transformer Oil:
1. Insulation: Transformer oil fills the gap between the windings and the core, isolating live parts and preventing partial discharge and short circuits. Its insulation strength is far higher than air, with a breakdown voltage exceeding 35kV/2.5mm, about 10 times higher than dry air, ensuring the safe operation of high-voltage equipment.
2. Cooling: During transformer operation, copper and iron losses occur in the windings and core. Transformer oil circulates and transfers heat to radiators or cooling devices. The oil's specific heat capacity is approximately 2.1kJ/kg·K, and its thermal conductivity is approximately 0.13W/m·K, effectively controlling temperature rise and preventing overheating of the insulation materials.
3. Arc Extinguishing: During switching operations or faults, the oil decomposes to generate gas, forming a pressure wave that quickly disperses the arc and restores insulation performance. High-quality transformer oil requires low viscosity (≤13mm²/s@40℃) and a high flash point (≥135℃), and its service life can be extended by adding antioxidants.
Condition Monitoring and Protection: The color, transparency, and water content of transformer oil reflect the operating status of the equipment. Darkening or milky turbidity indicates insulation aging or water content; timely detection can prevent equipment failure.
Classification of Transformer Oils: By Raw Material and Performance Type:
1. Mineral Transformer Oil: Refined from petroleum fractions, inexpensive, with good insulation and heat dissipation properties, but non-renewable, with a low flash point and prone to oxidation.
2. Vegetable Transformer Oil: Excellent electrical properties, good biodegradability, and strong environmental friendliness, suitable for new power system applications.
3. Silicone Oil Transformer Oil: Good high-temperature stability, suitable for special high-temperature or high-voltage scenarios, but with higher cost.
4. Synthetic Ester Transformer Oil: High flame resistance and long oxidation life, already used in high-speed trains and other applications, but requires high raw material purity and has complex processes.
5. Nano-modified transformer oil: Thermal conductivity and breakdown voltage are improved by adding nanoparticles (such as SiO₂ and TiO₂).
