Arc furnace power supply with converter circuit

A power supply system for an electric arc furnace, the power supply system comprising:

• an AC input connectable to an electrical grid and an AC output for supplying at least one power electrode of the arc furnace, wherein the AC input has at least two phases and wherein the AC output has at least two phases;
• converter circuits interconnected between the AC input and the AC output, wherein a converter circuit is interconnected in each phase of the AC input or in each phase of the AC output;
• and
• a transformer connected between the AC input and the AC output;
• wherein each converter circuit comprises at least one converter cell with a capacitor and semiconductor switches for series connecting the capacitor between a circuit input and a circuit output of the converter circuit;
• wherein the power supply system is adapted for switching each converter circuit into a bypass state during a start-up of the power supply system by closing a bypass switch, wherein the bypass switch is connected in parallel with the at least one converter cell of the converter circuit and is adapted for connecting and disconnecting the circuit input and the circuit output, and
• wherein the power supply system is adapted for controlling the converter cell for adjusting the electrode current and opening the bypass switch after energization of the transformer.