Refinement of Short-Circuit Withstand Capability Calculation for Power Transformers and Application in Fault Analysis

Power transformers inevitably face various short-circuit faults during their normal operational processes, and their ability to withstand these faults is a critical performance indicator. This article is based on actual data from a 110 kV three-phase double-winding power transformer that experienced a fault due to inadequate short-circuit withstand capability. It introduces a refined method for calculating the short-circuit withstand capability of power transformers, establishes a refined model for this capability calculation, and accurately calculates the axial and radial forces on each turn of wire in different operating conditions. The calculated results are compared with the dismantling phenomena of the faulty transformer, demonstrating that the calculated results effectively reflect the stress characteristics and weak points of the transformer’s coil components. This approach can significantly support the design optimization of transformer short-circuit withstand capability and facilitate fault analysis tasks.