In [1, 8], the frequency responses of transformers are modelled for
a broad frequency range from the industrial frequency up to 10 MHz.
However, the non-linear effects that occur at low frequencies,
originating from the effects in the core, are not considered in the
model.
A model used to simulate overvoltages transferred between
the transformer terminals is described in [2]. However, in the
proposed model, the frequency-dependent effects of the
ferromagnetic material in the core are not considered, since they
are represented by constant magnetising parameters.