Computational and experimental investigation of distribution transformers under differential and common mode transient conditions

Electromagnetic (EM) modeling of transformers is crucial for the prediction of critical behavior (short-circuit, overvoltage etc.) of the entire system. Time domain simulations and measurements have been performed in order to model the behavior of dry-type transformers under transient overvoltages in Common and Differential Mode configurations. This analysis and the developed method allow investigations of possible means of protection (or their possible redundancy) of the transformer against uncommon transients experienced in real circumstances that might exceed the dielectric stresses the transformer was designed for. For this purpose, an existing, detailed computational model [1] has been further developed, and the results have been benchmarked against measurements.