Study on transformer electric field in different degrees of insulation aging considering temperature effects

In the transformer operation process, as the time continues to rise, the transformer winding and core will generate heat. Transformer oil, as an important heat dissipation and insulation part of the transformer, absorbs the heat generated by the transformer winding and the iron core, resulting in varying degrees of aging of the transformer oil, which increases the conductivity of the transformer oil and the relative dielectric constant, resulting in a decline in the insulation performance of the transformer. This phenomenon is the main cause of transformer aging breakdown. Therefore, the electric field calculation of transformer insulation aging degree considering the influence of temperature is studied. First, the transformer temperature experiment is carried out with the use of a temperature control box to make the transformer reach the predetermined temperature. Second, the accelerated aging experiment, power frequency voltage withstand experiment, and transformer oil dielectric strength experiment are carried out to obtain the power frequency voltage withstand experiment results and the relative dielectric constant data of transformer oil under different aging conditions, and the experimental data are brought into the electric field calculation by Fourier function fitting. Finally, under different aging conditions of transformer oil, electric field simulation and numerical calculation were carried out and calculation results of the electric field are obtained.