Research on Radial Bending Stress of Power Transformer Windings under Short-Circuit Condition

When the transformer is subjected to a short-circuit, significant stress is generated in the transformer winding, which will make winding elastic and plastic deformation or even instability. Therefore, this paper focuses on a comprehensive analysis of the bending stress of the inner winding transformer under short-circuit faults, the coupled electromagnetic-structural analysis method is used to analyze radial bending stresses of transformer windings. Taking an 110kV power transformer as an example, the finite element model of transformer with the single wire for the unit is established. The leakage flux distribution and electromagnetic force is calculated under medium voltage symmetrical short-circuit condition during HV-MV operation. And the single span fixed beam model is used to calculate the bending stress of the inner winding. The results reveal that the stress is relatively high at the support point and the middle of the two spacers, and the stress distribution rule of inner winding is obtained.