FIELD: electricity.
SUBSTANCE: discloses a device and a method for controlling electric arc furnace (10) in the initial phase of a melting process. Sensor (16) for measuring the actual current and sensor (15) for measuring the actual flowing current are provided in each branch (7) of electric arc furnace (10). Actual impedance (Zactual) is calculated time-dependently by means of control and regulating unit (30). Load tap changer (20) is associated with furnace transformer (6) having primary side (6P) and secondary side (6S), said load tap changer being embodied as a semi-conductor step switch. Said semiconductor step switch (20) carries out a clock pulse rate in the range of 20 milliseconds.
EFFECT: invention prevents critical increase in current due to the fall and short-circuit of the material melted in the furnace, and thereby prolongs the life of electrodes and other components of the furnace power supply system.
8 cl, 4 dwg
