Electric Arc Furnaces (EAF) are growing in importance in steel making as scrap based metallurgy is gaining momentum all over the world. EAFs, as loads on the network, are characterized by high and strongly erratic consumption of reactive power, strong harmonic generation, as well as asymmetrical loading of its three phases. As a result, unless properly remedied, more or less heavily distorted currents and voltages will gain their way into the feeding grid, and once there, spread over the grid to other, neighboring facilities. This is particularly pronounced in cases where the fault level of the feeding grid is low, which is often the case for remotely located plants.
As a particularly annoying effect of EAF operation, flickering of incandescent lamps can arise, to detriment of the human environment far away from the source of the sensation. Harmonics and asymmetry between phases can lead to added losses in the grid, as well as malfunction and overheating of other plant connected to the grid. With steadily increasing furnace ratings, maintaining power quality in feeding grids has become an issue of growing concern. Also, not only open arc furnaces for steel production are an issue, but also in many cases submerged arc furnaces for alloy metal production (nickel smelters).
To parry the rapidly fluctuating consumption of reactive power of arc furnaces, an equally rapid compensating device is required. This is where FACTS come into the picture, in the way of SVC, or in more severe cases, STATCOMs. Likewise, SVCs come in for dynamic voltage stabilization of rolling mills operated by cyclo-converter as well as DC drives.
It is also worth noting that with a high and stable EAF bus voltage, there are prospects for more active power into the EAF, and thereby increased productivity of the process. Moreover, with SVC and STATCOM solutions, substantial money can be saved on the electricity bill by means of a much improved power factor (typically, a P.F. = 1 is attainable).