Abstract: An apparatus for regulating an electric arc furnace connected to a power supply system with at least one system phase that applies an AC voltage to a furnace electrode and an arc current for melting. A control loop device includes an electrical converter designed for negative feedback of an amplitude and/or frequency of the AC voltage to produce an amplitude and/or frequency of the arc current. The converter includes an input port having a system power supply connected thereto, and an output port having a melting furnace power supply and a primary circuit of a first transformer connected thereto, wherein a secondary circuit of the first transformer is connected to the arc furnace electrode. A primary coil of a second transformer is connected in parallel with the converter input port, and a secondary coil of the first transformer is connected in series with a secondary coil of the second transformer.

Abstract: A non-linear load in the form of an arc furnace with an upstream furnace transformer is supplied with electric power from a power supply device with a plurality of converter units. The converter units have a plurality of main modules with inputs connected to a respective phase of a three-phase grid. The converter units have a common star point between the main modules and the primary side of the furnace transformer. Each main module has a series circuit with a coupling inductance and a plurality of submodules. The submodules have a bridge circuit with four self-commutated semiconductor switches and a bridge path with a storage capacitor between input and output. The semiconductor switches of the submodules can each be switched independently of the semiconductor switches of the other submodules of the same main module and of the other main modules.

Abstract: Flicker values to be expected may be determined and achieve a high probability from suitable state and operating variables which are acquired during the first minutes in the initial smelting phase. In this way, flicker can effectively be reduced and kept below predefined limiting values. This is in particular suitable during steel production using electric arc furnaces.

Abstract: At least one measurement value of a measurement variable characterizing the operating state of each of a plurality of system components that influence the operating conditions of an arc furnace is detected and compared to a respective currently permissible threshold value for the measurement variable. A maximum power that can be supplied to the arc furnace within a time window while satisfying all currently permissible threshold values is determined based on the result of the comparison.

Abstract: In a method for operating an electric arc furnace operated with an alternating voltage, a structure-borne sound signal occurring on a wall of the electric arc furnace is detected, from which structure-borne sound signal a parameter characterizing the flicker properties of the electric arc furnace is calculated. At least one process variable of the electric arc furnace is controlled on the basis of the calculated parameter. An electric arc furnace operated according to the method is used in and for a melting plant.

Abstract: A non-linear load in the form of an arc furnace with an upstream furnace transformer is supplied with electric power from a power supply device with a plurality of converter units. The converter units have a plurality of main modules with inputs connected to a respective phase of a three-phase grid. The converter units have a common star point between the main modules and the primary side of the furnace transformer. Each main module has a series circuit with a coupling inductance and a plurality of submodules. The submodules have a bridge circuit with four self-commutated semiconductor switches and a bridge path with a storage capacitor between input and output. The semiconductor switches of the submodules can each be switched independently of the semiconductor switches of the other submodules of the same main module and of the other main modules.

Abstract: An apparatus for regulating an electric arc furnace connected to a power supply system with at least one system phase that applies an AC voltage to a furnace electrode and an arc current for melting. A control loop device includes an electrical converter designed for negative feedback of an amplitude and/or frequency of the AC voltage to produce an amplitude and/or frequency of the arc current. The converter includes an input port having a system power supply connected thereto, and an output port having a melting furnace power supply and a primary circuit of a first transformer connected thereto, wherein a secondary circuit of the first transformer is connected to the arc furnace electrode. A primary coil of a second transformer is connected in parallel with the converter input port, and a secondary coil of the first transformer is connected in series with a secondary coil of the second transformer.

Abstract: A method for controlling a melt process in an arc furnace, including a signal processing component, program code, and data medium for performing the method. Sound signals or vibrations from the interior of the furnace container are captured by solid-borne sound sensors, from which characteristic values can be derived representing the distribution of melting material, melt, and slag in the furnace fill. A characteristic values are generated in priority sequence for: thermal radiation impinging on the furnace wall of the container, the lumpiness of the melting material in the volume of furnace fill, and the change to the portion of solid melting material contacting the furnace wall. The energy distribution at the electrodes is chanced by a control system based on the characteristic values in priority sequence, such that thermal load peaks are dampened or even completely prevented.

Abstract: A basic materials industry facility having a type 1 electrical consumer with at least three working points that each have a respective expected power consumption is disclosed. The facility can also have type 2 or type 3 consumers, each having only two working points or a single expected power consumption assigned to them, respectively. Schedule diagrams for type 1 and 2 consumers define their working points as a function of time, taking into account technological criteria for the operation of the facility, and are continuously updated using actual energy consumption data in such a way that the expected total energy consumption between starting time point and a predefined end time point does not exceed a maximum permissible total energy consumption. Preferably the consumers are controlled so that the expected total energy consumption is brought close to the maximum permissible energy consumption.

Abstract: In a method for operating an arc furnace (2) with at least one electrode (3a, 3b, 3c), a solid material fed to the arc furnace (1) is melted by an arc (1) formed by the at least one electrode (3a, 3b, 3c). A measurement (MM) for the mass of one part of the solid material arranged on a boundary (2) of the arc furnace (1) is determined, and using the determined measurement (MM), a process variable of the arc furnace (1) is controlled and/or regulated. A method which can reduce the risk of electrode damage caused by metal scraps falling into the treated area is provided.

Abstract: Flicker values to be expected may be determined and achieve a high probability from suitable state and operating variables which are acquired during the first minutes in the initial smelting phase. In this way, flicker can effectively be reduced and kept below predefined limiting values. This is in particular suitable during steel production using electric arc furnaces.

Abstract: Two or more metallurgical sub-plants, a separate network for the distribution of electrical energy, at least one power generating plant with at least one gas turbine for the provision of electrical energy in the separate network, and a control device are included in a metallurgical plant. The sub-plants draw at least 80%, in particular at least 90%, of the electrical power required for their operation from the at least one power generating plant via the separate network. The control device controls provision of electrical power for a first sub-plant at the expense of at least one other of the two or more sub-plants. The two or more sub-plants include at least one steel works with at least one electric arc furnace and at least one sub-plant for a metallurgical process arranged upstream or downstream of the steel works.

Abstract: At least one measurement value of a measurement variable characterizing the operating state of each of a plurality of system components that influence the operating conditions of an arc furnace is detected and compared to a respective currently permissible threshold value for the measurement variable. A maximum power that can be supplied to the arc furnace within a time window while satisfying all currently permissible threshold values is determined based on the result of the comparison.

Abstract: A material is melted in an arc furnace by a plasma arc produced by at least one electrode. The plasma arc is regulated by one or more additional substances which influence the plasma composition introduced into the plasma, increasing the efficiency and output of the arc furnace.

Abstract: In a method for operating an electric arc furnace operated with an alternating voltage, a structure-borne sound signal occurring on a wall of the electric arc furnace is detected, from which structure-borne sound signal a parameter characterizing the flicker properties of the electric arc furnace is calculated. At least one process variable of the electric arc furnace is controlled on the basis of the calculated parameter. An electric arc furnace operated according to the method is used in and for a melting plant.

Abstract: In a method, a variable characterising an operational state of an electrode of an arc furnace can be determined. An electrode flow guided to the electrode is detected in the method and the structure-borne noise oscillations are detected. From the detected electrode flow, a flow evaluation signal associated with the frequency range of the detected electrode flow is determined. From the detected structure-borne noise oscillations, an oscillation evaluation signal that is associated with a frequency range of the detected structure-borne noise oscillations is detected and a quotient from the oscillation evaluation signal and the flow evaluation signal is formed as a radiation measurement for at least one frequency common to the detected electrode flow and the detected structure-borne noise oscillation.

Abstract: In a method for determining the size and shape value (M) for a solid material (S), in particular scrap metal, in an arc furnace (1), an electrode flow fed to an electrode (3a, 3b, 3c) for forming an arc furnace (L) between the electrode (3a, 3b, 3c) and the solid (S) is measured (30) and from the measured electrode flow (I (t)), an effective measurement value of the electrode flow is determined (31) and from the measured electrode flow (I (t)) (32), a flow part associated with a frequency range of the measured electrode flow is determined (32), and a quotient of the flow part and an effective measurement value is formed as a measurement of the shape and size value of the flow (M). Thus, a method is provided that enables a property of a fusible element introduced into one of the arc furnaces to be determined.

Abstract: An electric arc furnace, signal processing device, storage medium, machine-readable program code, and method for determining a time for charging (e.g., recharging) an electric arc furnace with material to be melted (e.g., scrap) are provided. The electric arc furnace may include electrode(s) for heating material inside the electric arc furnace by an electric arc. By detecting a signal for determining a phase state of an electric arc root on the side of the material to be melted based on a captured electrode current, by checking whether the signal exceeds a predetermined threshold value for a predetermined minimum duration, and by ensuring that the charging time is reached at the earliest when the signal exceeds the predetermined minimum duration threshold value, a state-oriented charging time for an electric arc furnace can be determined to reduce energy use, resource use, and production time for a production cycle to reach a tap weight.

Abstract: An arc furnace, a control and/or regulating device for an arc furnace, and a method for operating an arc furnace are provided, wherein an arc for melting metal is generated by at least one electrode, wherein an arc associated with the electrode(s) has a first radiation power based on preselected operating parameters, wherein the arc furnace is operated according to a predefined operating program based on an expected process sequence, wherein monitoring is performed to detect whether an undesirable deviation exists between the actual process sequence and the expected process sequence. Because a modified second radiation power is specified if a deviation is present, and a modified second set of operating parameters, e.g., impedance value(s), is determined based on the modified second radiation power, a method is provided that permits a minimal melting time while minimizing consumption of operating resources, e.g., with respect to arc furnace cooling.

Abstract: A device for controlling an arc furnace installation has an automatic controller (3) wherein a functional unit (6) for furnace control, a functional unit (7) for electrode control and a functional unit (8) for melting control are integrated in the controller (3).