The trend of designing electric arc furnaces (EAFs) aiming at higher productivity has led to power inputs of up to 300 MVA for AC EAFs.1 Accordingly, increased arc voltages and high currents allow for melting scrap rapidly and efficiently. Nevertheless, such high arc powers can cause tremendous damage to the furnace vessel once the arcs are burning on the liquid bath without any scrap covering the walls. Common meltdown controls are based on operational diagrams controlling the transformer tap, the reactor tap and the impedance setpoint depending on total energy input. Usually there is no on-line feedback from the process that adapts these operational diagrams.
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