Transformer oil is a petroleum-based liquid, potentially flammable, and has environmental drawbacks. However, due to its excellent performance and low price, the vast majority of power transformers still use transformer oil as an insulation and cooling medium.
At the end of the 19th century, transformer oil began to be used as an insulation and cooling medium in transformers, leading to the emergence of oil-immersed transformers. Besides its abundant natural reserves and low price, transformer oil has gained widespread use due to the following characteristics:
1) When used in conjunction with fibrous materials, it provides excellent insulation performance, reducing insulation distance and lowering costs.
2) Transformer oil has low viscosity and good heat transfer properties.
3) It effectively protects the core and windings from the effects of moisture in the air.
4) It protects insulating paper and paperboard from oxygen, reducing the aging of insulation materials and extending the transformer's lifespan.
Except for some special-purpose small and medium-capacity transformers and gas-fired transformers, the vast majority of large and medium-sized transformers still use transformer oil as a cooling and insulation medium.
Transformers impregnated with transformer oil have an insulation heat resistance class of A and a long-term operating temperature of 105℃.
