The effects of transformers phase-shifts on harmonic penetration calculation in a steel mill plant

Transformers phase-shifts can play an important role in the study of harmonic penetration within large industrial power systems. The incorporation of these quantities in the conventional linear frequency domain analysis (LFDA) technique leads to the problem of unnecessary long computation time and large memory requirements. Using a novel method, a comprehensive harmonic analysis code is developed as a new module in an existing software environment. The program is then used to analyze Iran's Foolad Mobarakeh steel mill plant consisting of eight arc furnaces, two static voltage controllers, and several hundred nodes including 372 transformers. The study of the results demonstrates the importance of transformer phase-shifts in determining the correct harmonic distortion level in an industrial power system with multiple harmonic sources.