27 Steady-State and Inrush Harmonics in a New Zealand Steel Mill on a Long Transmission Line

This project presents the first stage in an investigation and modelling of harmonics produced by a New Zealand steel recycling and manufacturing company’s electric arc furnace (EAF) on a long transmission line. Results are presented for both steady-state and inrush conditions, showing the EAF is a complex and time-variable load. A MATLAB model of the EAF, transformers, and transmission was built, and its performance on steady-state is compared to operational furnace. Steady-state currents were observed of 1.04kA with a significant (12.1 %) second harmonic, and an inrush current was observed of to be around 43kA. A single phase and three phase model was developed to simulate the industrial conditions and solutions to address the above harmonics were tested. In later work, the optimum placement of any power factor and/or harmonic correction devices will be considered.