Oil-immersed transformers typically use mineral insulating oil (transformer oil) as the insulation and cooling medium.
This oil is mainly refined from petroleum and possesses good insulation properties, thermal stability, and chemical stability, effectively preventing internal short circuits and overheating in the transformer. The main components of transformer oil are alkanes, cycloalkanes, and aromatics. It has a high flash point and low viscosity, facilitating flow and heat dissipation. Furthermore, transformer oil must have low acid value, low moisture content, and good oxidation resistance to ensure long-term reliability.
The selection of transformer oil must comply with international standards (such as IEC 60296) or national standards (such as GB 2536). Specific indicators include dielectric strength, viscosity, flash point, and pour point. In practical applications, transformer oil also requires regular testing and maintenance to prevent aging or contamination from affecting transformer performance. Common testing items include dissolved gas analysis (DGA), moisture content testing, and acid value determination.
Besides mineral insulating oil, synthetic ester oils or silicone oils may also be used in certain special applications. These oils have higher high-temperature resistance and environmentally friendly properties, but are more expensive. Synthetic ester oils are commonly used in transformers operating under high load or high temperature conditions, while silicone oils, due to their non-toxicity and high flash point, are suitable for applications with high safety requirements.
The following points should also be noted when using transformer oil: 1. Avoid mixing oils of different brands to prevent chemical reactions; 2. Store in a sealed, light-proof container to prevent oxidation; 3. Filter or change the oil regularly to maintain its per
