Abstract: A static convertor for power transmission by means of high-voltage direct current has a current regulator which influences the control angle of the convertor in dependence on the deviation between a current order supplied to the convertor and the present direct current of the convertor. The current regulator has a proportional part and an integrating part. The output signal of the integrating part is limited in the upward direction to a value corresponding to a maximum value of the control angle of the convertor. The output signals from the integrating and proportional parts are added to form the output signal of the current regulator. The limiting value of the integrating part is calculated by a calculating circuit as a function of the current order and the ideal direct voltage of the convertor. The calculation is made by determining the control angle at which, at a load current equal to the current order, the extinction angle becomes equal to the smallest permissible turn-off angle.