An arrangement for reducing a DC field component in the core of a transformer includes a compensation winding magnetically coupled to the core of the transformer, and a DC generator arranged in series with the compensation winding and with a reactance dipole. The reactance dipole is formed from a parallel circuit of an inductance and a capacitor to feed into the compensation winding a compensating current opposite in sense to the DC field component in the core. The inductance is formed from magnetically coupled first and second windings having N1 and N2 turns respectively, such that N2/N1