Chopping of Transformer Magnetizing Currents Part II: Three-Phase Transformers

For assessment of the overvoltages accompanying interruption of the transformer magnetizing current, three-phase transformers were modeled with the transient behavior of the magnetic core represented. Switching from the delta connected side of transformer banks and three-leg core transformers, as is common in medium voltage systems, was considered. Maximum overvoltages were calculated and their probability distribution for different core saturations was derived.