Improving the reliability of steel producing units electric supply with schematic design solutions

The electrical equipment of modern metallurgical units - electric arc furnaces, section and sheet mills of hot and cold rolling, has undergone a number of significant changes over the past decades. This resulted in an increase in the unit power of transformers and converters, the massive introduction of microprocessor control systems, and the complication of internal plant power supply schemes with significant own generation of electric energy. Consequently, the electric drives of continuous production, primarily rolling mills, have become more sensitive to voltage dips and interruptions in power supply. The aim of this work is to increase the reliability of power supply to metallurgical units using the rational choice of the configuration of 110 kV networks based on the analysis of various circuitry solutions. The consequences of emergency situations are usually assessed based on two indicators - short-circuit current and residual voltages of responsible consumers. It has been proved that the most radical way to reduce the first indicator and increase the second is to convert a 110 kV complex closed circuit into independent circuits with a simple configuration. This provides for a significant reduction in short-circuit currents, a reduction in the number of emergency situations, as well as a reduction in active power losses in 110 kV networks. The total annual effect of the implementation of the proposed activities exceeds 40 million rubles.