基于“场-路”耦合有限元分析法的变压器短路电抗仿真的研究

短路电抗法是检测电力变压器绕组变形的有效方法之一,开展变压器短路电抗的仿真计算研究,对于获取各种绕组变形故障时的特征信息具有重要意义。基于实验室中一台模型变压器的结构参数,分别建立了绕组正常及存在匝间短路故障时的有限元仿真模型,利用"磁-路"耦合的方法对变压器的漏磁场和漏感参数进行了计算,分析了绕组变形位置与变压器漏磁场之间的关系,并与在模型变压器上的实验结果进行了对比,结果表明:绕组内部发生匝间短路故障时,在径向中部的匝间短路对漏磁场的影响较大,而在轴向中层绕组的匝间短路对漏磁场的影响较小。研究成果对于指导短路电抗法的现场应用和绕组故障的检测提供了一定的理论依据。

Simulation of Transformer Short-circuit Reactance with FEM by Coupling Magnetic Field with Electric Circuit

The short-circuit reactance method is one of the effective measures to detect the transformer winding deformation.Simulation of transformer’s short-circuit reactance can help one achieve feature information from various winding deformation.In this paper,two finite element models of normal winding and the winding with turn-to-turn short-circuit fault are established,respectively,based on the structural parameters of a model transformer.The leakage magnetic field and the leakage inductance of the transformer are calculated with FEM by coupling magnetic field with electric circuit,and the relationship between the location of winding deformation and the leakage magnetic field of transformer is analyzed.The simulation data is compared with the experimental one of the model transformer.The result demonstrates that when there exists a turn-to-turn short-circuit fault in winding,the fault at middle part of windings in the radial direction has comparatively greater influence on leakage magnetic field,while the fault at middle part of windings in the axial direction has comparatively smaller influence on leakage magnetic field.This study may be helpful to field application of short-circuit reactance method and detection of transformer winding deformation.