Browsing by Keyword "Electrical Efficiency"
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Item New sensor for Electric Arc Furnaces arc stability control(Associazione Italiana di Metallurgia, 2018) Vicente, Asier; Velasco, Arturo; Linares, Miguel; Picon, Artzai; Arteche, Jose Antonio; Sainz, Jose Angel; Digital Base; COMPUTER_VISIONDuring the last decades the strategy to define the optimal Electric Arc Furnaces (EAF) electrical operational parameters has changed several times. Probably one of the major advances has been the development of the foaming slag practice, which allows operating with very high-power factors on the last stages of melting process ensuring higher energy consumption efficiency and reducing the electrode consumption. As 90% of steel using electric route is made in Alternating Current (AC) EAFs, and due to the fact that the arc stability is higher in AC because of shorter arc lengths, most of the efforts done to increase the arc efficiency have been conducted on AC technologies such as Rogowski coils [1] and acoustic signal processing techniques [2]. However, for Direct Current (DC) Electric Arc Furnaces, there are few certificated commercial systems that have proved their validity as voltage regulators to optimize arc stability so far and all of them required high CAPEX and complex sensor installation and integration. In this work we analyse the magnetic field variation vector around the DC EAF and their relationship with the arc stability. This have allowed the development of a cheap stability control system with no installation or integration requirements easily implementable to any EAF. The solution described is based on a non-intrusive and low cost Hall-effect sensor that can be mounted neighbouring the furnace's electrical bars. The sensor captures the magnetic field magnitude and analyses the acquired signal providing an arc stability factor metric. The calculated stability factor serves as a closed loop signal to the electrical regulation PLC for controlling the arc voltage, ensuring the most convenient arc length that guaranties non-instabilities. The new system was developed and industrially installed at two different DC EAF's in ArcelorMittal in Spain demonstrating a clear improvement in the overall energy efficiency of the melting process. Several tests were also carried out in other ArcelorMittal AC EAF in Spain proving the capability of this technology for both types of furnaces.