Method for aligning the load graph powerful induction plants
The paper deals with the issues of load balancing in the shop power supply system containing powerful electrothermal installations. There is a cyclical change in load parameters with significant variations in current and power factor during operating multi-section induction installations of methodical action. The largest deviations of these parameters occur in transient modes at heater start or at changing the billets nomenclature. It is shown that when the load changes in starting modes, an increase in power and a decrease in the power factor can lead to unacceptable current overloads of the power supply. Correction during start-up of section currents and power factor allows us to reduce current fluctuations, to provide a smoother power diagram and eliminate power supply overload. It is possible to implement current and power factor correction using semiconductor frequency converters in each section. This approach prevents decreasing the voltage quality indicators and reduces possible deviations of the billets temperature distribution. The parameters of the heater sections in transient modes are calculated. The ranges of power, voltage, current and frequency variation are determined, corresponding to the capabilities of semiconductor frequency converters used in these installations. The proposed start-up algorithm provides the smallest of all possible power fluctuations.