Analysis and Solution of the Luminosity Variations in a Steelmaking Industry Caused by the Operation of a Flying Shear

Despite the emergence of new lighting technologies, such as LED, high pressure sodium lamps (HPS) driven by electromagnetic ballasts are still widely diffused in industrial facilities, mainly due to high acquisition costs related to more modern devices. Nevertheless, when subjected to variations in its supply voltage, such device produces considerable luminosity changes, as shown in this present case-study, in which periodic variations of approximately 5% in the voltage, resulting from the driving of a flying shear of a hot rolling mill, cause variations of illuminance in the workplane superior to 10%. The hassle from such event, reported by workers, motivated the realization of this study, in which two solutions were proposed to solve the problem, which are the use of (i) electronic ballasts and (ii) LED lamps, being the latter chosen to be employed in a field test due to its technical-economic superiority. For the development of the work reported in this paper, it was initially made a detailed characterization of the functioning of the equipment responsible for causing the undesired voltage variations, as well as of the current lighting system. Local measurements were made for the illuminance and voltage profile, along with laboratory tests to characterize the HPS lamps performance. Taking into account acquisition, installation, operation and maintenance costs, along with lighting requirements, a comprehensive technical-economic analysis was performed to find the best solution for the real problem addressed in this paper.