This research work proposes to detect arc conditions of electric arc furnaces (EAFs) based upon digital signal processing of the line to ground three-phase voltage measurements at the secondary side of the furnace transformer. It uses the voltage difference between a virtual-neutral point of the symmetrical power source and the furnace shell ground voltage. For harmonic analysis this voltage is processed using Fourier transform. The obtained information is found to be useful to detect arc operational conditions like arc stability, arc balance, and arc slag coverage. With the here in proposed arc indicators, the power control of the EAF can be performed using the concept of a dynamic power profile to set the operational transformer tap and current set points of the EAF control systems.