电力变压器辐向承受短路能力的校核计算

Check Calculation of Radial Withstand Short-Circuit Ability for Power Transformer

基于平衡状态分枝型失稳理论,将有限元模型的单元刚度矩阵和静态结构分析得到的预应力矩阵相结合,建立了计算单匝导线屈曲变形的特征方程。通过屈曲分析,可以得到变压器线圈的辐向极限力及不同极限力作用下的屈曲形态。本文对几起变压器内线圈的辐向抗短路能力进行了校核计算,试验证明了本文所提方法的合理性。在此基础上,对影响线圈辐向稳定性的因素进行了研究。结果表明,增大导线尺寸和保证撑条的有效支撑都可以提高线圈的辐向稳定性。其中,增大导线的辐向厚度对改善绕组稳定性的效果最明显。

The finite element stiffness matrix and the prestressed matrix of static structure are combined to establish critical loading formulas of the single turn model. Based on the bifurcation instability theory, the whole stability of the transformer winding is analyzed by buckling method, so as to get the buckling critical loads and displacement. The algorithm is verified by numerical examples.At the same time, the influence factors of stability are studied. Results indicate that the windingrs ability of radial resisting short-circuit can be effectively improved by increasing the wire gauge size and the number of spacers.