3D Fixed-Point Finite Element Method for Time Periodic Problems with Subsynchronous Components and Analysis of Transformer Electromagnetic Characteristics
Sun Jia’an, Li Lin
State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing 102206 China
Abstract：The injection of subsynchronous frequency components causes periodic asymmetric bias of the transformer core. Taking the 3D magnetic vector potential A and the winding current I as the unknown variables, combining the fixed-point method and the field-circuit coupled relationship, a 3D time-periodic finite element model for calculating the magnetic field of the transformer core was established to study the steady-state magnetic properties of transformer core with subsynchronous frequency components. In the pre-processing, the current density direction vector was established for each element in the winding area. During the iteration, it is necessary to select a suitable local convergence fixed-point magnetoresistance for the non-linear anisotropic core region. The steady-state current calculated by the 2D time-periodic finite element method is used as the initial value of the 3D field-circuit coupled calculation to reduce the total iteration time. The calculation and experimental results were used to verify the effectiveness of the algorithm, and the effects of different amplitudes, frequencies, phase sequences and subsynchronous frequency components of three-phase distribution on the electromagnetic characteristics of transformer were analyzed.
孙佳安, 李琳. 考虑次同步分量下时间周期问题的三维定点有限元法及变压器电磁特性分析[J]. 电工技术学报, 2022, 37(14): 3475-3486.
Sun Jia’an, Li Lin. 3D Fixed-Point Finite Element Method for Time Periodic Problems with Subsynchronous Components and Analysis of Transformer Electromagnetic Characteristics. Transactions of China Electrotechnical Society, 2022, 37(14): 3475-3486.
2022, Vol. 37 
