Characteristic Analysis of Transformer Loss with Subsynchronous Components by Field-Circuit Coupled Time Periodic FEM

A field-circuit coupled finite element calculation model embedded loss separation theory is proposed, which can effectively deal with the nonlinear core loss of transformer caused by subsynchronous frequency components injection. In order to deal with the increased time period due to the subsynchronous frequency components, and the problem of excessive loss current and too small parallel resistance due to zero-crossing point of voltage, the Parareal algorithm is introduced to solve the model. The algorithm is verified by the experiments of the physical transformer under the conditions of rated fundamental voltage and with subsynchronous components, respectively.