Operational Dynamics of Induction Melting Furnace and its Effect on Power Quality of Grid

Induction melting furnaces (IMF) are used in steel plants for the melting of metallic scrap and various alloys. The IMF is well in demand and gradually becoming a major contributor in steel plants. In steel plants and foundries, the complete melting cycle of the IMF consists of various stages like scrap charging into the furnace, melting, refining, alloy addition and then holding it before pouring of molten metal for further process of casting. During all these processes, the electrical parameters of the power converter switching system of the IMF get change which affects the power quality of the grid supply. In this paper, the effect of characteristic and uncharacteristic harmonics of the IMF system on the power quality of grid supply is demonstrated by performing harmonic analysis of supply current, voltage and inverter current for the various stages of the melting process. Dynamic load behavior of the operation of IMF has been investigated based on simulation and practical field data results. Simulated results are verified against experimental field result of trials conducted on the actual working IMF system in the steel plant. The close agreement between the simulated and the experimental results, highlights the experimental work and may be helpful for designing of harmonic mitigation systems