Short Circuit Electromagnetic Force Analysis of 500 kV Autotransformer Based on Field-Circuit Coupling

As transformer capacity and voltage levels continue to rise, the short-circuit resistance of transformers has become an important factor affecting the stability of the power grid. When a short-circuit fault occurs, the interaction of short-circuit current and leakage magnetic field will generate large electromagnetic forces in the winding, which will lead to winding deformation or even cause the transformer to withdraw from operation. Therefore, it is crucial to calibrate and analyze the short-circuit electromagnetic force of the winding. Currently, the short-circuit electromagnetic force is mainly studied using the traditional finite element analysis method. Combining the field-circuit coupling method with the traditional finite element method can more accurately simulate the circuit state during a short-circuit fault and thus obtain a more accurate leakage magnetic field distribution. In this paper, the leakage magnetic field distribution of a 500 kV autotransformer is simulated and analyzed based on the field-circuit coupling method, and the short-circuit electromagnetic force distribution is obtained. At the same time, the case of axial offset of the winding is considered, and the effect of the offset on the short-circuit electromagnetic force distribution is compared and analyzed.