Simulation Modeling of Lumped Parameter Circuit for Power Transformer Winding Based on the Finite Element Method

Equivalent circuit of transformer winding is usually combined with the frequency response method to analyze the frequency response mechanism and winding condition. The modeling of winding is a necessary basic work. Therefore, we proposed a modeling method of transformer winding based on finite element method. The finite element simulation software ANSYS Maxwell was used to establish an actual power transformer(400 k VA, YNyn0) model. The computational methods of equivalent longitudinal capacitance based on single disk of interleaved winding and sequential winding were deduced. Combined the model and the algorithm, main circuit parameters of the transformer were calculated, and an equivalent lumped parameter circuit of the high voltage winding was built. Moreover, healthy and short circuit fault windings were simulated and experimentally researched. The research results show that the winding mode is an important factor to be considered in winding modeling. The trends of simulated and measured sweep frequency response curves of the health winding and short circuit fault winding are approximately identical, part of the resonant frequencies of the resonant points are almost coincident. The third, fourth, sixth, seventh resonant peaks and the second, fourth, sixth, seventh, ninth resonant valleys of simulated frequency response curves are consistent respectively with the maximum error of 6.76%. The correctness of circuit model and computational method are verified. This modeling method is intuitive, convenient, simple, and can not only be used to explore more transformer winding deformations, but also assist in the realization of fault pattern recognition in the future.