Balancing Busbar Packages in the Secondary Current Leads of Ore-Reduction Thermal Furnaces

Abstract

The design of short power-supply networks for ore-reduction thermal furnaces (submerged-arc electric furnaces) should provide a minimum of active and inductive resistance and their phase symmetry. The mutual arrangement of the power source and the working space of such furnaces determine the different lengths of a rigid fixed section in a short network, which leads to an asymmetry of the short power-supply network as a whole, to an uneven power density throughout the entire working space, and, therefore, to an uneven wear level of the lining and to a reduced furnace productivity. At high currents, the phases are split into parallel conductors and, if possible, half-phases are realigned in order to reduce their inductive resistance. The section of the short power-supply network under consideration is made of rectangular busbars or tubular busbars. Novel variants for the transposition and realignment of busbar packages for round ore-reduction thermal furnaces have been proposed in order to equalize the phase inductance with no significant changes in the size of the busbar packages. The novel variants have been assessed via a numerical simulation of electromagnetic processes occurring in the elements of a short power-supply network in a two-dimensional formulation using an ANSYS software package. Specific examples for balancing busbar packages in operating furnaces are presented.