Transformer losses can be as high as 7% of the electrical inputs. These losses will depend mainly on the sizing and age of the transformer. Converting the furnace operation to higher power, or more specifically to ultra-high power (UHP), increases productivity and reduces energy losses. The increased power can be reached by installing new transformers or paralleling existing transformers. The UHP operation may lead to heat fluxes and increased refractory wear, making cooling of the furnace panels necessary. This results in heat losses that partially offset the power savings.

In a French plant the operating voltage increased from 600V to 660V in one furnace and from 400V to 538V in the second. In turn the power delivered by the electrodes at both furnaces increased. Electrode spraying was introduced as a cooling method. The higher power delivered has decreased the power on time by 7 and 14 minutes leading to a productivity increased by 7 ton of crude steel per hour. The electrode consumption decreased by 0.1 kg/t and 0.5kg/tThe new transformer system also increased the transformer reactance and made it possible to obtain a higher stability of the electric arc (Worrell et al, 2010. p. 91).