Furfural Dynamic Diffusion Process in Oil-Paper Insulation System

Furfural analysis for transformer aging estimation will be influenced by temperature or oil replacement. The establishment of relevant correction methods should take furfural diffusion process into consideration. In this paper, according to the accelerated thermal aging tests, furfural diffusion process under 4 different temperatures and 4 different aging stages was investigated. Based on the Fick's second law, furfural diffusion coefficients under different temperatures and aging stages were calculated, and then the furfural dynamic diffusion model was constructed which was verified by experimental data. Results showed that furfural diffusion was influenced by temperature and aging condition. The higher temperature is or the deeper aging condition is, the faster furfural diffused and the easier the equilibrium state achieved. A calculation method of furfural diffusion equilibrium time for field transformers was provided. The testing of furfural will be reliable after furfural diffusion reaching the equilibrium state. © 2017, The editorial office of Transaction of China Electrotechnical Society. All right reserved.