Analysis of Transformer Minor Turn‐To‐Turn Short Circuit Characteristics Based on Electromagnetic‐ Structural‐ Thermal Field Coupling Simulation

ABSTRACT

As a core component of the power system, the transformer's safe and continuous operation will directly affect the quality of electricity for the nation. The turn‐to‐turn short fault of the winding is one of the biggest hidden dangers to the safe operation of the transformer. People are concerned about the characteristics of severe inter‐turn short circuits because they are very likely to cause protective actions; however, the physical characteristics of winding when a minor turn‐to‐turn short fault happens are not well summarized. To investigate the changes of relevant characteristic parameters before and after the minor turn‐to‐turn short circuit, this study establishes the field‐coupling model of the transformer with stranded‐type winding. The electromagnetic‐structural and electromagnetic‐thermal transient coupling simulation is completed, and the spatial and temporal distributions of electromagnetic, mechanical, and thermal parameters of this transformer under turn‐to‐turn short circuits are obtained. Simulation analysis also offers significant advantages in determining the insulation state level of the windings during a turn‐to‐turn short circuit.