Method of setting optimum asymmetric mode of operation of electric arc furnace

Design of Improved Control Algorithms for Ladle Furnaces With Analysis of Electric Arc Current Harmonic Composition

“…Для режима работы аварийной фурмы использованы только две пары граничных значений коэффициента шлака на повышение рабочей кривой (K ГР1.1 , K ГР2.1 , K ГР1 , K ГР2 ) и, соответственно, три значения рабочих кривых с N РК = 4 до N РК = 6 с различной несимметрией горения дуг. Во втором случае увеличение номера рабочей кривой соответствует уменьшению длины электрической дуги и увеличению несимметрии длин электрических дуг с учетом расположения возмущения на поверхности жидкого металла, создаваемого работой аварийной фурмы [11,12].…”

“…Для обеспечения оптимальных значений тепловых КПД электрических дуг при изменении режима аргонной продувки и толщины шлака для указанных выше рабочих кривых N РК введены различные балансовые коэффициенты K БАЛ1,2,3 к уставкам импеданса Z 2Ф1,2,3 вторичного электрического контура УКП. На основании проведенных ранее экспериментальных исследований, описанных в [11,13], было показано, что для обеспечения стабильного горения дуг [14,15] и сохранения теплового КПД при увеличении диаметра зеркала металла длины дуг, определенные заданием импеданса вторичного электрического контура Z 2Ф.ЗАД. , в ближайших к зеркалу металла фазах должны быть уменьшены, а в фазе, которая находится на удалении от источника возмущений, -увеличены.…”

Optimal control of the electrical mode of an arc furnace on the basis of the three-dimensional vector of phase currents

“…The mathematical and computer models of control systems of electric arc furnaces operation modes suggested in [3][4][5][6][7] have some advantages and disadvantages, which are determined by the completeness and accuracy of the description of electric modes, by the complexity and precision of state identification, and by the conveniences in use and adjustment. The results obtained in these works demonstrate a slight improvement in energy efficiency and electromagnetic compatibility, firstly due to the use in the synthesis of controlling influences of the models that with a not high accuracy describe the nature of the real processes of changing the coordinates of the electric mode, as well as due to the high level of sensitivity of the indicators of the quality of the dynamics to the change of the parameters of an object to be controlled, which is extremely undesirable under the conditions of non-stationary parametric continuous disturbances in the furnace power circuit and in the phase arc intervals.…”

“…The time dependencies of changes in the values of the elements of these arrays reflect the stochastic properties of the processes of change of the phase currents on the current stationary interval. In the last block 9 of this cycle, taking into account the current active values of phase currents I A , I B , I C , the calculation of the controlling influences u A , u B , u C of each phase of the control system of the arc furnace electric mode is performed on the basis of the obtained mathematical model (5).…”

Synthesis and Analysis of Arc Furnace Electrical Mode Control System on the Basis of Three-Dimensional Phase Currents Vector Distribution

“…The mathematical and computer models of control of electrical modes of the three-phase arc furnaces proposed in the papers [5][6][7][8][9] have certain advantages and disadvantages among themselves in terms of the completeness and accuracy of the description of modes, identification of states, conveniences in use and readjustment, but they do not meet the above requirements for energy efficiency and electromagnetic compatibility modes in full, primarily due to the inadequacy of the control models to the nature of the real processes of changing the coordinates of the EM, also because of the high sensitivity of the obtained dynamics to changing parameters of the control object, which is highly undesirable in terms of continuous action of stochastic parametric disturbances in the power circuit of the furnace and in phase arc gaps.…”