Power quality improvement in DC electric arc furnace plants utilizing multi‐phase transformers

SUMMARY Conventional feeding systems for DC electric arc furnace steel making plants usually include a 12-pulse rectifier that is fed by Δ/Δ and Δ/Y three-phase transformers. In this paper, with the use of the PSCAD/EMTDC software (Developed by Manitoba HVDC Research Center Inc., Canada), the advantages of applying multi-phase transformers for supplying such loads are evaluated and compared with the traditional three-phase power supply systems. A well-designed secondary winding for multi-phase transformer is proposed, and then the modeling of such transformers is discussed. With some proper power quality indices applied, it is shown that utilizing multi-phase transformers can lead to power quality improvement such as current/voltage harmonic reduction and unbalance mitigation. Copyright © 2012 John Wiley & Sons, Ltd.