Abstract: The present invention is directed to a circuit for controlling induction in current transformers so as to maintain such induction at a level below its saturation level in presence of a primary current having an asymetric component. The control circuit comprises a detection part connected to the secondary of the current transformer for detecting an increase in the transformer induction; an auxiliary load of high resistive value at the secondary of the transformer; and a switching part governed by the detection part operative to insert the auxiliary load in series with the secondary of the transformer when the polarity of the secondary wave reaches a polarity inverse with respect to the asymetrical component of the primary current.