Influence of non-uniform temperature on transient electric field for +/- 500 kV converter transformer under polarity reversal voltage

摘要

In order to investigate the impacts of the non-uniform temperature on the electric field distribution under PR (polarity reversal) voltage, the core loss and windings loss of a +/- 500 kV converter transformer are calculated based on the electromagnetic theory firstly. Then the 2D fluid-thermal model of the converter transformer is adopted, and the temperature distribution under normal condition is obtained by utilizing the CFD software of Fluent. Afterward, the thermal data obtained from the mesh for computation of fluid-thermal field is mapped to the mesh for computation of electric field based on interpolation, and finally the transient electric field distributions under different PR voltages are computed by the time stepping finite element method. The comparisons of the electric field distributions under different PR voltages at uniform and non-uniform temperature are conducted, which provides a reference for insulation design and fault analysis of the converter transformer.