Computational and Experimental Investigation of Distribution Transformers Under Differential and Common Mode Transient Conditions

Electromagnetic modeling of transformers is of paramount importance for the prediction of the transient behavior of the entire system during atmospheric overvoltages and switching transients. Time domain simulations and measurements have been performed to model the behavior of dry-type transformers under transient overvoltages in different 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 has been further developed, and the results have been benchmarked against measurements.