THE DYNAMIC MODEL OF AN ARC FURNACE IN MATLAB (SIMULINK)

The article shows that for creation of electric arc model it is appropriate to use the methods of investigation of electric arc with changing its parameters through time. The comparison of four different models of volt-ampere characteristic of the AC arc in the arc steel furnace showed that three of these four models did not allow obtaining a consistent range of higher harmonics of current and voltage generated by electric arc furnaces. They do not display the inertia of thermal processes during the arc ignition and extinction as a result of which the curves of current and arc voltage in these models differ from the actual furnace arcs oscillograms. To compare the results of the arc voltage-current characteristics modeling against each other and with the results of experimental studies, the model of one phase of electric power supply system with electric arc steel furnace was created in Matlab (Simulink). While calculating the higher harmonics of current and voltage, the equivalent circuit parameters of a furnace transformer and a low-voltage circuit for a DSP-100NZA furnace with a furnace transformer capacity of 50 MVA were used. The authors obtained the diagrams of arc voltage, the voltage on low voltage buses of furnace transformer and the arc current for each model of volt-ampere characteristic. The research showed that more coincidences of the results of harmonic analysis of currents and voltages with experimental data is observed for the VAC model, which takes into account the inertia of thermal processes in the arc and the electrodes.