Effect of Temperature on 2-Furfural Partitioning in the Oil-paper System of Power Transformers

2-furfural content in oil is a valuable indicator of cellulose paper degradation and is widely utilized in aging assessment for power transformers. However, with the same aging degree of insulation paper, the actual 2-furfural content in oil is influenced by temperature because 2-furfural partitioning behavior in the oil-paper insulation system of power transformers changes with temperature. Thus, correction of the temperature effect on 2-furfural partitioning is crucial for accurate assessment of the aging of power transformers. In this research, oil-paper samples with different 2-furfural contents were prepared through an accelerated thermal aging test. A 2-furfural equilibrium experiment was conducted at different temperatures to construct a 2-furfural partitioning diagram. Results showed that 2-furfural partitioning behavior is influenced by temperature. At high temperatures, 2-furfural tends to migrate from paper to oil. To correct the temperature effect on 2-furfural partitioning, a 2-furfural correction factor was developed to normalize 2-furfural contents in oil at different temperatures to a reference temperature. And the 2-furfural correction factor was verified by experimental data.