电缆绕组变压器线圈短路机械强度的计算

在变压器T型等值电路基础上,求得变压器短路最严重情况对应的起始条件和出现最大短路电流时刻。以此起始条件设定变压器原边电压激励,利用“磁路-电路”耦合有限元法建立了2D轴对称模型,计算了变压器原、副边线圈及各线匝短路电磁力。以出现最大轴向和径向电磁力的线匝为研究对象,结合电缆绕组变压器的受力特点,建立了单线匝短路条件下的静态和动态有限元模型。选择第四强度破坏理论,分别计算了静态和动态时线匝相当应力分布。讨论了静态时相当应力与预紧压强、撑条根数的关系;分析了相当应力随时间的变化规律,并与静态对应情况进行了比较。

Calculation to Short-Circuit Mechanical Strength for Powerformer Windings

The initial conditions and the time corresponding to most serious states of short-circuit were deter mined based on the T-model of power transformer.Considering the conditions as voltage at primary winding,shortcircuit forces of windings and turns for transformer were calculated with FEM coupling circuit method under the 2D symmetrical model.Focusing the turn subjected to the maximum axial and radial forces,the static and dynamic finite element models were presented for the single turn,and the stress distributions were calculated under static and dynamic states respectively.The relationships of equivalent stress with prepress and spacer numbers were discussed,and the equivalent stress via time was investigated comparatively.