Current stabilization system for non-ferrous metal electrolysis based on an alternating voltage regulator with a booster transformer and a 12-pulse diode rectifier

Бесплатный доступ

This paper considers a current stabilization system (CSS) for non-ferrous metal electrolysis (NME) based on a three-phase alternating voltage regulator (VR) with a booster transformer (BT) and a 12-pulse diode rec-tifier. The system differs from prior art by its improved indicators of electromagnetic compatibility (EMC) of the com-plex with the power supply network due to reduced reactive power consumption and improved supply voltage quality. The DC voltage (current) is regulated at the CSS output by switching taps in the rectifier transformer (RT) and regula-ting the alternating voltage between the taps using the VR on the high voltage side. The paper proposes a control system for the VR which provides for the automatic switching of the RT taps with a smooth regulation of the alternating voltage in the in-phase and antiphase modes between the taps. It allows cutting the VR power in half and, as a consequence, its cost. The proposed system also compensates for higher harmonics of the voltage at the VR output caused by the nonlinear input current of the 12-pulse diode rectifier, which improves sup-ply voltage quality. The efficiency of the current stabilization system based on the VR with the BT is confirmed by computer modeling in the MATLAB + Simulink environment. It was used to compare the results with a widespread cur-rent stabilization system, in which the DC voltage is jointly regulated by the phase control of thyristors or saturable reactors and switching of the RT taps on the primary side. The experimental dependences of tgφ, the power factor, and harmonic distortions of the network current and voltage are presented depending on the regulation depth of the 12-pulse rectifier within the first switching zone of the no-load tap changer (NLTC-1) in the rectifier transformer. The obtained results showed that in the nominal operating mode of the CSS based on the VR with the BT, compared to the CSS based on the thyristor or saturable reactor phase control method, the maximum consumption of reactive power decreases from 0.422 to 0.267 (according to the average value within one tap from 0.348 to 0.267), and the voltage distortion coeffi-cient of the network decreases from 8.8 % to 6.2 % (according to the average value within one tap from 7.7 % to 6.2 %) at a given ratio of the network short-circuit power. This will allow non-ferrous metal electrolysis enterprises to avoid fines for excess permissible reactive power or additional capital investments in the purchase of expensive equipment for reactive power compensation, as well as to improve the EMC and operational reliability of the complex.

Еще

Current stabilization system, non-ferrous metal electrolysis, alternating voltage regulator, booster transformer, 12-pulse diode rectifier, electromagnetic compatibility

Короткий адрес: https://sciup.org/147252015

IDR: 147252015   |   УДК: 621.314   |   DOI: 10.14529/power250303