Browsing by Author "Linares, Miguel"
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Item Magnetic field-based arc stability sensor for electric arc furnaces(2020-02) Vicente, Asier; Picon, Artzai; Arteche, Jose Antonio; Linares, Miguel; Velasco, Arturo; Sainz, Jose Angel; COMPUTER_VISIONDuring the last decades the strategy to define the optimal Electric Arc Furnaces (EAF) electrical operational parameters has been constantly evolving. Foaming slag practice is currently used to allow high power factors that ensures higher energy efficiency. However, this performance depends on strict electric arc stability control. Control strategies for these are normally defined for alternating current furnaces (AC EAF) and are based on intrusive and highly expensive systems. In this work we analyze the variation of the magnetic field vector around the direct current EAF (DC EAF) and its relationship with arc stability. We propose a cheap stability control system with no installation or integration requirements and thus, easily implementable to both AC and DC EAFs. To this end we have built a non-intrusive and low-cost 3-axis Hall-effect sensor that can be mounted neighboring the furnace’s electrical bars. The sensor allows acquiring the magnetic field magnitude and orientation that provides a newly defined arc stability factor metric. This proposed Arc Stability Index has been compared with three different alternative well established and more expensive measurement methodologies obtaining with similar results. The proposed index serves as a closed loop signal to the electrical regulation for controlling the arc voltage, ensuring the most convenient arc length that guaranties non-instabilities. The new system was developed and industrially validated at two different DC EAF’s in ArcelorMittal demonstrating an improvement of 6.7 kWh per Liquid steel ton during the evaluated period and a time reduction of 1.1 min per heat over the current standard procedure. Additional validation tests were also carried out also in ArcelorMittal AC EAF proving the capability of this technology for both AC and DC of furnaces.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.