Apparatus and method for controlling an electric arc furnace in the initial phase of a melting process

摘要

An apparatus and a method for regulating an arc furnace (10) in the initial phase of a melting process is disclosed. A sensor (16) for measuring the current voltage and a sensor (15) for measuring the current flowing are provided in each strand (7) of the arc furnace (10). The actual impedance (Zist) is calculated as a function of time using a control and regulating unit (30). An on-load tap changer (20), which is designed as a semiconductor tap changer, is assigned to a furnace transformer (6), with a primary side (6P) and a secondary side (6S). The semiconductor stage switch (20) realizes a cycle time of a few milliseconds.