Increasing the Speed of the Control System of the Thyristor Compensator of Reactive Power of Electric Arc Furnaces

Electric arc furnaces (EDP) contain furnace transformers with a power factor of 0.3, which randomly consume reactive power in the form of jumps when non-sinusoidal currents are present. Thyristor reactive power compensators (TRPC) are used to compensate for the latter. When reactive power jumps occur, the known TCRP control system provides a regulation time of 0.02 s, since it determines the control angle of the thyristors for the last period of the mains voltage. At the same time, during the transient processes of TCRP regulation, the reactive power of the EAF is not compensated. The aim of the work is to increase the speed of the TPRC control system in order to reduce uncompensated reactive power in transient control processes. The goal is achieved by the fact that, unlike the known control system, the control angle is determined every half-period by solving the equation of minimizing the functional of the root mean square error of the equality of the reactor current and the transformer current with a capacitor at the moments of the amplitude value of the mains voltage. As a result, the speed of the control system increases to 0.01 s. The scientific novelty of the work lies in the further development of the expression of the functional for determining the control angle of the TCRP at each half-period of voltage. Practical significance: doubling the speed of the TCRP control system reduces reactive power consumption in transient control processes by half and increases the resulting power factor to unity. The performance of the proposed TCRP control system has been verified on a mathematical model