基于有限元法电力变压器绕组的短路电动力分析

Short-circuit force analysis of power transformer winding based on finite-element method

当电力变压器遭受短路故障时,短路瞬变电流导致绕组承受巨大的电动力,可能会造成绕组的变形,甚至使变压器发生绝缘和机械故障,因此计算短路电动力大小、探究其分布特点有助于预测短路后变压器绕组的变形情况,对变压器设计具有参考价值。文章通过有限元软件ANSYS Maxell建立三相变压器的二维和三维模型,并利用该模型分析三相短路后绕组轴向和辐向电动力。利用有限元法仿真得到的短路电流结果与公式计算的电流结果具有高度一致性,这充分说明有限元模型及其计算方法的可靠性。仿真结果表明,绕组两端受轴向力最大,辐向力最小;中部受辐向力最大,轴向力最小。

When a power transformer is submitted to a short-circuit condition, the short circuit transient current gener- ates a huge force on winding which causes the deformation of windings or even makes the insulation and mechanical structure of power transformer breakdown, therefore, calculating the force and analyzing its characteristic are helpful to predict the deformationof power transformer winding, which also can provide reference to the design of transformer. In this paper, 2-D and 3-D models of three-phase transformer are built by finite-element software ANSYS Maxell which are used to calculate the axial and radial electromagnetic forces of winding. The short circuit current results obtained by FEM are compared with the calculation results by formula, and they show good agreement, which verify the relia- bility of FEM model and the simulation method. The results show the axial force on both ends of winding is bigger than that on middle, and the radial force on middle of windings is bigger than that on both ends.