Numerical study of dissolved H2 migration in a 500 kV transformer ascending flanged base

The ascending flanged base of the transformer is a so-called dead oil area with very low flow velocity, leading to possible delay of characteristic gas migration to the DGA sampling location. In this paper, the temperature-dependent diffusion coefficient of H2 in transformer oil is obtained via bubble dissolution method and molecular dynamics simulation, and then the migration of dissolved H2 in the ascending flanged base of a 500 kV transformer is numerically studied. It is found that the natural convection changes the original internal flow field of the ascending flanged base, and the characteristic gas diffuses faster than that under constant temperature. However, it is still difficult for the characteristic gases to diffuse into the transformer tank in time to reach the oil sampling point. The presented results can serve as reference for optimizing fluid design and oil chromatography detection.