Assessing the feasibility of electrical mode control of ultra-high power arc steelmaking furnace based on data about harmonic composition of arc currents and voltages

The article deals with the feasibility assessment of electrical mode control of an electric arc furnace (EAF) using data about higher harmonics of currents and arc voltages. Field re-search was carried out at the operating EAF-180 (150 MVA) of the OJSC “MMK” (Russia, Magnitogorsk) to show the relation-ship between the level of harmonic component of arc current and technological stages of the heat. It was proved that data about higher harmonics of current correlates with heat stages better than electric power consumption, which at present is a common parameter used in most control systems. Diagnostics of heat stages using higher harmonics of arc currents was used with the diagnostics of heat stages using piezoelectric accelerometers installed at the furnace shell. The results of the experiments correlate well with each other. Mathematical model of the EAF electrical circuit was used to study the influence of the main parameters of an electric arc on the levels of higher harmonics of currents and arc volt-ages, and graphs reflecting these relationships were developed. The research group offered an alternative way of changing EAF electrical modes based on the data about higher harmonics of arc voltages.