Survey of arc-furnace installations on power systems and resulting lamp flicker

THE ELECTRIC arc furnace is usually considered a desirable load because of its good load factor and its high power factor. However the violent load variations, predominantly single-phase, which occur particularly during melt-down, make it a difficult load to supply because of the objectionable voltage fluctuations and lamp flicker which can result. The magnitude of these load fluctuations compared to the average furnace load is much greater than that existing for most large industrial loads. Designing a power system for supplying a large arc furnace requires much greater attention to flicker considerations than other types of loads and may actually require that special equipment be installed to correct undesirable flicker conditions.