Apparatus and method for dynamically adjusting electric arc furnace

Abstract

The invention relates to an apparatus and a method for dynamically regulating an electric arc furnace (1) that is electrically connected to a power supply system and that has at least one system phase that is used to apply to a furnace electrode an electrical AC voltage having an amplitude and a frequency and to supply an arc current, which is required for melting, having an amplitude and a frequency, wherein a control loop device (3) that has an electrical converter (5) is designed for negative feedback of the amplitude and / or the frequency of the AC voltage to produce the amplitude and / or the frequency of the arc current, the converter (5) is a two-port network (11) having an input port (7) and an output port (9), wherein the input port has a system power supply connected to it and the output port has a melting furnace power supply connected to it, the output port (9) has a primary circuit of a first transformer (13) electrically connected to it, in whose secondary circuit the furnace electrode of the electric arc furnace (1) is electrically connected. The invention is distinguished in that a primary coil of a second transformer (15) is electrically connected in parallel with the input port (7) of the converter (5), and a secondary coil of the first transformer (13) is electrically connected in series with a secondary coil of the second transformer (15).

Description

technical field [0001] The invention relates to a device for dynamically regulating an electric arc furnace and a corresponding method according to the preambles of the independent claims. Background technique [0002] The arc, in particular in the case of a three-phase AC supply, feeds the furnace with electrical energy in the form of an arc via 3 graphite electrodes. Such a furnace is, for example, an electric arc furnace (EAF). For this purpose, the medium or high voltage is usually converted down to low voltage by means of a furnace transformer and fed to the electrodes. The arc can be moved up or down mechanically to ignite the arc, then arc voltage and current are adjusted via distance, thereby adjusting coupled power. Because the current in each phase goes to zero twice per cycle, there is a risk of arc extinction when the current in the opposite direction is not established at a high enough rate of current rise before the existing plasma cools down too much . [...

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Problems solved by technology

As a result, the electric drive components may not be used optimally

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