Computer investigation of voltage fluctuations on the power busbars of an arc steel-melting furnace

Abstract

The intensification of production and the development of electrical technologies result in increased energy intensity and concentration of electrical loads. There is a growing number of nonlinear, phase-asymmetric, and rapidly changing dynamic electricity consumers. Typical representatives of such consumers are arc steel-melting furnaces (ASF). Their operation negatively impacts the quality indicators of electrical energy in distribution networks, necessitating the development of solutions to bring their values within regulatory standards. Traditionally, developed solutions are generally aimed at mitigating the consequences of their operation by increasing the power capacity of the energy system and implementing dynamic reactive power compensation installations. This article proposes a two-loop structure for an automatic control system (ACS) of the electrical regime of ASF. Unlike the aforementioned traditional approach, the solutions proposed in this study are primarily aimed at suppressing disturbances within the power electrical circuits of the ASF itself, significantly reducing the negative impact of their operation on the quality indicators of electrical energy, particularly on voltage fluctuations on the power busbars of the ASF. This is achieved through a substantial increase in responsiveness, phase-wise autonomy in disturbance control, and the expansion of the functional capabilities of the ACS for the electrical regime of the ASF to implement adaptive multi-criteria optimal control strategies. These properties are additionally provided to the control system by the inclusion of a high-speed electrical current control loop in its structure, which functionally enables the formation and rapid implementation of desired artificial external characteristics of the arc furnace. The effectiveness of the proposed solutions was examined using a created computer model of the ACS for the ASF DSP-200, which incorporated the proposed solutions. In the article, a comparative analysis was conducted through computer modeling of the dynamics, electromagnetic compatibility, and energy efficiency indicators of the proposed two-loop ACS and the serial power controller ARDM-T-12 for the ASF DSP-200 arc furnace. The obtained research results confirmed an increase in the dynamic accuracy of stabilizing the coordinates of the electrical regime and a reduction in voltage fluctuations and deviations in the electrical network. Specifically, the current dispersion of the arcs at different technological stages of melting decreased by 4.5-7 times, the electrical network voltage by 3-4 times, and the reactive power by 5-7.5 times.7.5.