Análise do impacto dos desequilíbrios de tensão na operação de uma planta industrial de conformação de aço

Abstract

Unbalances are a common phenomenon in three-phase electrical systems. In the industrial scenario, voltage imbalances can cause several damages to the system operation, causing malfunction and loss of efficiency of the plant. In this regard, this study aims to analyze the impact of voltage imbalances on the operation of an industrial steel forming plant, which is supplied at 13.8 kV by the local power utility. To this end, practical and computational studies were carried out. The practical studies were conducted based on field measurements using an energy analyzer. The computational studies were performed through computational modeling of the industrial plant in MATLAB/Simulink software. Using the aforementioned resources, two case studies were carried out, the first focusing on the impact of voltage imbalances on the origin of industrial current imbalances and the second aimed at evaluating the influence of voltage imbalances on the harmonic generation of the plant. In the first case study, based on field measurements, voltage and current imbalances of 1.57% and 17.34%, respectively, were found. Although the voltage imbalance is below the regulated limit, it contributes to the high incidence of unscheduled power outages. In addition, it was found that the origin of current imbalances in the industry is mainly associated with the unbalance of the supply voltage. In the second case study, it was found that the total harmonic distortions per phase were below the limits established in PRODIST. However, the voltage imbalances intensified the total harmonic distortions of voltage and current, since they cause the emergence of non-characteristic harmonic components such as 3rd, 9th and 15th order. It is worth noting that the computational modeling developed proved to be a robust tool and can be used in future studies of the industrial plant.