Research on digital twin modeling method of transformer temperature field based on POD

For the calculation of transient fluid–solid coupling temperature field of transformer, the traditional Galerkin finite element full order model has the defect that the calculation time is up to hours-level, which is difficult to meet the timeliness requirements of the digital twin model. Firstly, the implementation architecture of transformer digital twin based on IoT is established, and the necessity of multiphysical field simulation and model reduction technology for building the digital twin model is introduced. Then, based on the method of transformer digital twin implementation,it is proposed to combine the proper orthogonal decomposition (POD) with the finite element (FE) to establish the Galerkin FE full order model for the governing equation of the transient temperature field, the reduced order mode composed of the first several bases is intercepted to build the reduced order model of transient fluid–solid coupling temperature field. Finally, the POD reduced order model is applied to calculate the temperature rise of a transformer. According to the actual transformer temperature rise test, the temperature values of different measuring points are selected to compare the calculation error and time of the reduced order model and the full order model. The results show that the error between the third order model and full order model meets the criterion of POD truncation error, and the calculation time is shortened by 192 times, which can meet the seconds-level calculation requirements.