Abstract
The paper considers the most energy-intensive object of the steelmaking complex, particularly, the electric arc furnace (EAF-125) of a metallurgical open Joint-stock company "AMURMETAL", Komsomolsk-on-Amur. The authors described the functional role of the static thyristor compensator (STC). The simplified scheme of electric power supply of the EAF is given. The insufficient speed of hydraulic drives moving the furnace electrodes is indicated, which leads to the arc extinction. Stepwise regulation of the voltage at the input of the furnace transformer (FT), with the help of an on-load tap changer, leads to the loss of continuous control over the technological process of steelmaking. When switching the stages of the on-load tap changer, short-circuits can arise between the coils, which create electrodynamic shock loads on the transformer windings reducing the reliability of the FT. The research group suggested a technical solution, which makes it possible to replace the on-load tap changer, providing continuous adjustment of the voltage within the predetermined range on the high side of the FT. Mathematical models of reactor-thyristor voltage regulator (RTVR) and its control system were developed in "MatLab" environment. The paper shows a block - modular simulation model of RTVR with real parameters. Numerical experiments were conducted to investigate its regulatory properties and its influence on the network. Oscillograms of current and voltage of the device elements are considered. The results of the study showed that the process of regulation does not effect significantly the current and voltage; the mode of intermittent current does not arise. The possibility of using a thyristor voltage regulator with natural switching (TVRN), which is part of STC, is considered.
Keywords
Arc steel-smelting furnace, thyristor valve, reactor-thyristor voltage regulator, arc current, furnace transformer, static thyristor compensator, on-load tap changer.
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