For continuous or spiral windings which feature multiple continuously transposed conductors (CTC) wound in parallel, the transposition structure is commonly used to suppress circulation between conductors. This introduces a local asymmetry in transformer windings. Fault analyses have shown that building an asymmetric structure in transformers increases deformation risk in these windings. Researchers have yet to fully investigate this asymmetric structure. This study was conducted to observe the influence of transposition structure in a 110 kV transformer. The conductor’s relative position forms three patterns during the transposition process; two parameters are established to describe the position-changing process. A finite-element method (FEM) model is built to investigate the magnetic field and electromagnetic force distributions. The results indicate that the transposition structure distorts the magnetic field distribution. The maximum distortion factor of the axial component of magnetic flux density ( $B_{\mathrm {z}}$ ) along the axial direction caused by the transposition structure is 14.6%. The transposition structure only changes the radial change slope of $B_{\mathrm {z}}$ . The gap caused by the transposition process aggravates imbalance in the ampere-turns distribution, increasing the amplitude of the radial component of magnetic flux density ( $B_{\mathrm {r}}$ ) at the middle height of the transformer low voltage (LV) winding. The maximum amplitude of $B_{\mathrm {r}}$ at the transposition structure increases by 513%. The Lorentz force over the CTCs remains constant from before to after the transposition process, though its linear density over the CTCs is unevenly distributed throughout. The axial component $F_{\mathrm {z}}$ varies from −31 to 10 kN/m, while the radial component $F_{\mathrm {r}}$ varies from −146 to −51 kN/m. The results show that the initial stage of the CTC height rising segment is a weak point and should be strengthened in the manufacturing process.

中文翻译：

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变压器绕组换位结构的短路电磁力分布特性

对于具有多个平行缠绕的连续换位导体 (CTC) 的连续或螺旋绕组，换位结构通常用于抑制导体之间的循环。这在变压器绕组中引入了局部不对称。故障分析表明，在变压器中构建非对称结构会增加这些绕组的变形风险。研究人员尚未充分研究这种不对称结构。本研究旨在观察 110 kV 变压器中换位结构的影响。换位过程中导体的相对位置形成三种模式；建立了两个参数来描述位置变化过程。建立有限元方法 (FEM) 模型来研究磁场和电磁力分布。结果表明换位结构扭曲了磁场分布。磁通密度轴向分量的最大畸变因子（ $B_{\mathrm {z}}$ ) 沿轴向由换位结构引起的为 14.6%。转置结构只改变径向变化斜率 $B_{\mathrm {z}}$ . 换位过程引起的间隙加剧了安匝分布的不平衡，增加了磁通密度径向分量的幅值（ $B_{\mathrm {r}}$ ) 在变压器低压 (LV) 绕组的中间高度。最大振幅 $B_{\mathrm {r}}$ 在换位结构处增加了 513%。CTC 上的洛伦兹力在转座过程前后保持恒定，尽管其在 CTC 上的线性密度在整个过程中分布不均匀。轴向分量 $F_{\mathrm {z}}$ 从 -31 到 10 kN/m 不等，而径向分量 $F_{\mathrm {r}}$ 从 -146 到 -51 kN/m。结果表明，CTC高度上升段的初始阶段是一个薄弱点，应在制造过程中加强。