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Continuous success of DC EAF power supplies
By Daniel Sager, Shripad Tambe, Räto Stadler, and Rajesh Pai
Rectifiers, SVC, DC EAF, electrode control
DC power supplies are widely used in the steel and non-ferrous industries. With increasing pressure from utility companies to their big industrial customer to be clean (low flicker, tighter power factor requirements and no unbalanced load), DC EAF tech-nology continues to demonstrate advantages over AC electric arc furnaces. EAF plants are often located close to the mine site, i.e. in a rural area far away from the next power station. Accordingly, the utility’s electricity network is normally too weak for big industrial consumers, considering that a minimill easily consumes 400 MVA. Such conditions make DC EAF the ideal answer, and therefore, continuing to focus DC technology while improving safety, reliability, efficiency, maintainability and performance makes sense.
The new controller family for improved current control features a fast direct link to the SVC control in order to achieve shorter power-on-time and higher average power input, as well as an enhanced electrode control. This software tool helps to optimize current and electrode control in analysing the best parameters depending on raw material conditions and melting progress.
Two applications show that equipping the DC EAF with SVC results in efficient flicker reduction thanks to the rectifier control’s direct link with this control system. Keeping the rectifier transformer energized during tapping but disconnecting and grounding the furnace on the DC-side leads to increased system availability by simultaneously reducing risks, furnace downtime and maintenance costs.
In addition, make sure to read these articles:
On the possibility of cold deformation of medium-carbon low-alloy steel strengthened by bainitic transformation
Steel VIP - Pierre Gugliermina, Chief Technology Officer, ArcelorMittal
Evolution of the temperature profile of a controlled cooled rod section under varying durations of water quenching
Continuous success of DC EAF power supplies
Non-metallic inclusions and their distribution in the ladle before and after vacuum treatment of tool steel
Rheological model for microalloyed steels in a wide range of temperatures
Innovations in temperature controlled rolling in combination with expert systems
Physical and numerical modelling of steel process optimization
Modern charge design calculation using a computer-aided programme package
Mathematical model of deformation of round bars in a rectangular roll pass
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