On the Calculation of Economic cross-section for large D.C. busbars

Abstract

BUSBARS for aluminium reduction cells carry direct current from one cell to another and the passage of current results in power losses due to resistance. Electrical resistance for a given material being propo-rtional directly to length and inversely to area of cross-section, the power losses can be reduced by short-ening the length of busbars and increasing the area of crosssection. The length of busbars is determined by the design of the cell and facility in operation. The crosssection can be increased within practical limits but, for a given length, an increase in the cross- section will involve higher capital expenditure as more material will be used. In short, the initial investment in busbars varies directly with the area of cross-section of the busbars and subsequent operating costs, i.e. power, lost as heat due to resistance, varies inversely as the area of cross-section. The total costs incurred over the operating life of busbars are the initial investment followed by the stream of operating costs and the choice of cross-section should intend to minimise the total costs.