Finite Element Analysis of Oil-paper Insulation Nonuniform Aging in Transformer

In order to study the nonuniform aging of the transformer main insulation, this paper designs an experiment and carries out frequency domain dielectric spectroscopy (FDS) testing and conductivity measurement to obtain material performance parameters required for simulation. Using the Comsol simulation software, a two-dimensional simulation model of the main insulation inside the transformer was established, and the finite element analysis in the frequency domain was carried out. The differences of field strength distribution, current density mode and space charge density between the models under uniform aging conditions and those under nonuniform aging conditions were compared and analyzed. Compared with the uniform aging, at low frequencies, nonuniform aging causes that high electric field strength is concentrated on the outermost insulating pressboard; the current flow path changes, and most of it flows through the oil gap-barrier; the accumulation position of free carriers changes.