片间短路时变压器铁芯涡流场的三维建模与分析

Three Dimensional Modeling and Analysis of Eddy Current Field of Transformer Core with Interlaminar Insulation Faults

由于变压器铁芯每级叠片的尺寸不同等原因,当前用于电机定子铁芯故障的二维方法难以适用。为得到故障时变压器铁芯局部磁通及涡流分布的变化,进而为优化设计提供相应的仿真依据,本文提出故障时变压器铁芯故障点的等效电导率,且基于此建立牵引变压器三维有限元故障模型;其次利用该模型对故障时变压器铁芯内部的磁通分布、涡流分布以及涡流损耗进行仿真研究;最后采用较精确的涡流损耗计算方法——等效电路法对涡流损耗的仿真结果加以验证。结果表明:该有限元故障模型对涡流损耗的仿真结果与等效电路计算结果相近,证明该模型对变压器片间短路故障仿真的有效性。

Due to different size of each lamination layer of a transformer core,the current two-dimensional method for the motor stator core faults is not suitable for transformer core.In order to obtain the change of local magnetic flux and the eddy current distribution of transformer core during its fault,and then provide the appropriate simulation basis for optimized design,firstly,the equivalent conductivity of the fault points was proposed,and then a three-dimensional FEM model of a traction transformer with faults was established.Secondly,the model was used to simulate the flux distribution,the eddy current distribution and the eddy current loss inside the core.Finally,the equivalent circuit method,as a more accurate calculation method of eddy current loss,was utilized to verify the simulation results of the eddy current loss.The results indicate that the simulation data on the eddy current loss calculated by the three-dimensional FEM are similar to the results obtained by the equivalent circuit method.It proves the validity of the model for simulating the transformer＇s interlaminar faults.