The Effectiveness of Resonant Harmonic Filters of Ac Arc Furnaces in Uneasy Mode

Resonant harmonic filters are commonly installed on the primary side of the arc furnace transformer, and conse-quently, the transformer is exposed to the furnace generated current harmonics, the furnace reactive and unbalanced currents. The effectiveness of resonant harmonic filters installed directly at the furnace terminals, i.e., on the secondary side of the furnace transformer, is investigated in this paper. Such filters operate in conditions of fast varying parameters of the furnace. This can cause a decline in the filter effectiveness of harmonics reduction and a decline in the effectiveness of the power factor improvement. This paper investigates the effectiveness of resonant harmonic filters in an uneasy mode of an arc furnace operation. This study should enable us to draw some quantitative conclusions on the usefulness of resonant harmonic filters installed directly on the furnace.