Comparative Analysis of Mechanical Properties of Power Transformer Windings in Short-Circuit Fault Under Different Preload Loading Modes

The insufficient ability to withstand short circuit of power transformer seriously affects the safety of power system, so it is very necessary to calculate short circuit strength of windings accurately. Two-dimensional electromagnetic-structure coupling method is applied to calculate the mechanical properties of windings for a 110 kV power transformer and the stress and axial displacement of the transformer windings are analyzed and compared in short-circuit fault under the two kinds of commonly used preload loading modes, which are loading at one or both ends of the windings. The result reflects the stress and displacement distribution of the windings are different under the two kinds of preload loading modes. Considering the symmetry of the mechanical performance distribution of windings in practical engineering, the method of preload loading at both ends of the windings in numerical simulation of the mechanical performance of the windings is more accurate.