Harmonic analysis in power systems and regulatory standards: impact of electric arc furnaces in steel mills

Abstract

In the operation of power systems, voltage and current harmonics can arise due to loads such as steel plants, cement factories, or the effect of wind and solar generation. Electric Arc Furnaces (EAFs) are among the leading causes of voltage harmonics and fluctuations in the steel industry. These voltage harmonics can significantly increase the levels of current harmonics in the network, resulting in active power losses and equipment damage. Conversely, precise models of EAFs are not available for conducting harmonic studies in power systems due to their highly chaotic behavior.
This research proposes a short- and medium-term harmonic analysis methodology based on Ayrton’s simplified mathematical model for representing the EAF. This methodology is applied to an actual study case of a steel plant connected to the Bolivian power system. Quality of energy indices, and total and individual harmonic distortion rates were calculated, and compliance with the considerations of the IEEE 519-2022 standard was verified.
The results were compared with specialized harmonic measurements at high-voltage nodes of the Bolivian power system, evidenced by the significant contribution of harmonics in the network, mainly the fifth, seventh, eleventh, and thirteenth-order harmonics. Thus, the importance of complying with regulatory standards regarding energy quality to avoid affecting network users is demonstrated.