Improving the efficiency of electric arc furnaces through improved control algorithms for electrical modes

Abstract

The aim of this study is to increase the efficiency of electric arc furnace through the use of advanced control algorithms for electrical modes. It was established that despite the common structure of the electric control system, as well as the approach to diagnosing the stage of the technological process, the criteria for switching from one combination of the furnace transformer tap and operating curve to another for electric arc furnaces and ladle furnaces are different. So, for EAF it is advisable to use a system in which a separate analysis of the signals of the relative effective value of the total even and odd harmonics of electric arc current (voltage) should be applied. It’s important to note that at the initial stage of melting it’s preferable to use even harmonics, and at the final stage of melting - odd harmonics. In it’s turn, during melting in LF, the argon blow mode and the slag mode have a significant role. Intensive blowing modes lead to the appearance of a metal mirror with the occurrence of bursts that occure short-circuit of the electric arc and lead to not optimal electric mode. According to the results of the analysis, a number of recommendations have been formulated that can have practical application in modernizing of modern control systems, aimed at optimizing production energy costs and reducing the unit cost of the final product of the metallurgical cycle. Moreover, the experience of implementing the described ides shows (for shaft-type electric arc furnace with capacity 125 ton, 85 MVA and ladle furnace 25 MVA) that the economic effect is 2.5% in terms of saving electric energy and 2% in terms of saving the consumption of electrodes. It’s a significant indicator taking into account the high energy intensity of modern electric steelmaking shops. This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project No. FZRU-2020-0011).