Process for electrode control of a DC arc furnace, and an electrode control device

A process for electrode control of a direct current arc furnace, comprising the steps of:

• providing a rectifier control signal and a predetermined electrode control reference input signal;
• controlling direct current intensity of an arc current to a predetermined current reference value by said rectifier control signal;
• and
• controlling an electrode distance between at least one adjustable electrode and a melting bath of the arc furnace as a function of the difference between the predetermined electrode control reference input signal and the rectifier control signal, wherein the rectifier control signal is filtered within a predetermined frequency bandwidth prior to comparison with the electrode control reference input signal.

A process for electrode control of a direct current arc furnace, comprising the steps of:

• providing a rectifier control signal and a predetermined electrode control reference input signal;
• controlling direct current intensity of an arc current to a predetermined current reference value by said rectifier control signal;
• and
• controlling an electrode distance between at least one adjustable electrode and a melting bath of the arc furnace as a function of the difference between the predetermined electrode control reference input signal and the rectifier control signal, wherein the electrode control reference input signal is formed as a function of the predetermined current reference value wherein a predetermined phase is maintained, the phase not exceeding a predetermined phase limit.

An electrode control apparatus for controlling a position of an electrode in a direct current arc furnace, said apparatus comprising:

• a rectifier;
• an adjustable electrode connected to said rectifier;
• a direct current controller for generating a rectifier control signal which is input to said rectifier for controlling said rectifier;
• an electrode positioning means for setting a distance between said electrode and a melting bath of said arc furnace;
• an electrode controller for controlling said electrode positioning means according to said rectifier control signal;
• and
• means for filtering said rectifier control signal, said filtering means being connected between said current controller and said electrode controller.

An electrode control apparatus for controlling a position of an electrode in a direct current arc furnace, said apparatus comprising:

• a rectifier;
• an adjustable electrode connected to said rectifier;
• a direct current controller for generating a rectifier control signal which is input to said rectifier for controlling said rectifier;
• an electrode positioning means for setting a distance between said electrode and a melting bath of said arc furnace;
• an electrode controller for controlling said electrode positioning means according to said rectifier control signal, said rectifier control signal being a firing angle signal for the rectifier;
• and
• a summer for receiving an electrode control reference signal, a difference between said rectifier control signal and said electrode control reference signal being input to said electrode controller.

A method of controlling a position of an electrode in a direct current arc furnace, said method comprising the steps of:

• providing a rectifier control signal and an electrode control reference signal;
• filtering said rectifier control signal;
• determining a difference between said filtered rectifier control signal and said electrode control reference signal;
• and
• setting a distance between an adjustable electrode and a melting bath of said arc furnace according to said difference.

A method for electrode regulation of a direct current arc furnace, said method comprising the steps of:

• a) supplying direct current from an alternating current network via a controlled rectifier;
• b) regulating the direct current by a current regulator as a function of a detected actual current value of direct current to the arc furnace and by a predeterminable command current value, which current regulator furnishes the rectifier with a rectifier control signal;
• c) filtering said rectifier control signal;
• d) regulating electrode spacing between at least one adjustable electrode and a melt bath of the arc furnace using an electrode regulator;
• and
• e) regulating the electrode spacing based on a difference between a predeterminable electrode regulator guide variable signal and the rectifier control signal of the current regulator.